Brake distribution method and vehicle

Abstract

The present application discloses a braking distribution method and a vehicle, the method comprising: obtaining vehicle load information of the vehicle; determining the front and rear axle adhesion limits of the vehicle based on the vehicle load information and the environmental information of the vehicle; in response to receiving a vehicle braking request carrying a target braking force, based on the motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits, using a braking distribution strategy to distribute the target braking force between electric braking force and friction braking force; wherein the distribution priority of the electric braking force in the braking distribution strategy is higher than the priority of the friction braking force, and the total braking force of the front and rear axles is not greater than the front and rear axle adhesion limits.

Description

Technical Field

[0001] The present application relates to the field of control, and in particular to a braking distribution method and a vehicle. Background Art

[0002] With the popularity of electric vehicles, motors have brought powerful energy recovery functions, also known as electric braking functions. This function significantly improves the battery life of electric vehicles, but at the same time has a huge impact on the stability of the deceleration process.

[0003] In the prior art, in order to improve the stability of the rear wheels and from the perspective of functional safety, the maximum energy recovery braking torque of the vehicle is usually limited, and the deviation from the braking demand torque is partially compensated by the hydraulic brake. However, the limitation of the maximum energy recovery braking torque and the electro-hydraulic coordination (the coordination between the electric brake corresponding to the energy recovery braking torque and the friction braking torque provided by the hydraulic brake) give priority to the cruising range, and the rear axle is more involved. This is not a significant problem on dry asphalt roads, but on wet asphalt and icy and snowy roads, there will be obvious interference to the rear axle: the rear wheels will slip first, and then the relevant anti-skid function will be activated for control. Since control can only be intervened after slippage is detected, coupled with the time delay and execution deviation caused by the inevitable "calculation-arbitration-request-execution" process of the control process, the stability of the vehicle will be further reduced. Summary of the invention

[0004] In view of this, embodiments of the present application at least provide a braking distribution method and a vehicle.

[0005] The technical solution of the embodiment of the present application is implemented as follows:

[0006] On the one hand, an embodiment of the present application provides a braking distribution method, the method comprising: obtaining vehicle load information of a vehicle; determining the front and rear axle adhesion limits of the vehicle based on the vehicle load information and the environmental information of the vehicle; in response to receiving a vehicle braking request carrying a target braking force, based on the motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits, using a braking distribution strategy to distribute the target braking force between electric braking force and friction braking force; wherein the distribution priority of the electric braking force in the braking distribution strategy is higher than the priority of the friction braking force, and the total braking force of the front and rear axles is not greater than the front and rear axle adhesion limits.

[0007] On the other hand, an embodiment of the present application provides a vehicle, including a memory and a processor, wherein the memory stores a computer program executable on the processor, and the processor implements the steps in the method when executing the program.

[0008] In the embodiment of the present application, the vehicle load information of the vehicle is obtained; based on the vehicle load information and the environment information of the vehicle, the front and rear axle adhesion limits of the vehicle are determined; in response to receiving a vehicle braking request carrying a target braking force, based on the motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits, the target braking force is brake-distributed between the electric braking force and the friction braking force using a braking distribution strategy; wherein the distribution priority of the electric braking force in the braking distribution strategy is higher than the priority of the friction braking force, and the total braking force of the front and rear axles is not greater than the front and rear axle adhesion limits. Based on the principle of stability priority, the electric braking force is given priority, and the remaining braking force is distributed to the friction braking force without destroying the stability boundary. In this way, a balance can be achieved in energy recovery efficiency and stability, and the stability of the vehicle can be guaranteed to the maximum extent.

[0009] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present application and are used together with the specification to illustrate the technical solution of the present application.

[0011] Figure 1 A schematic diagram of an implementation flow of a braking allocation method provided in an embodiment of the present application;

[0012] Figure 2 A schematic diagram of an implementation flow of a braking allocation method provided in an embodiment of the present application;

[0013] Figure 3 A schematic diagram of an implementation flow of a braking allocation method provided in an embodiment of the present application;

[0014] Figure 4 A schematic diagram of an implementation flow of a braking allocation method provided in an embodiment of the present application;

[0015] Figure 5 A schematic diagram of an implementation flow of a braking allocation method provided in an embodiment of the present application;

[0016] Figure 6 A schematic diagram of an implementation flow of a braking allocation method provided in an embodiment of the present application;

[0017] Figure 7 A schematic diagram of an implementation flow of a braking allocation method provided in an embodiment of the present application;

[0018] Figure 8 It is a schematic diagram of an implementation flow of a braking distribution method provided in an embodiment of the present application;

[0019] Fig. 9 It is a schematic diagram of an implementation flow of a braking distribution method provided in an embodiment of the present application;

[0020] Fig.10 It is a schematic diagram of an implementation flow of a braking distribution method provided in an embodiment of the present application;

[0021] Fig.11 It is a schematic diagram of an implementation flow of a braking distribution method provided in an embodiment of the present application;

[0022] Fig.12 It is a schematic diagram of an implementation flow of a braking distribution method provided in an embodiment of the present application;

[0023] Fig.13 is a schematic diagram of a brake distribution control system provided in an embodiment of the present application;

[0024] Fig.14 It is a schematic diagram of the overall logical framework of a system provided in an embodiment of the present application;

[0025] Fig.15 It is a schematic diagram of the allocation of a braking allocation method provided in an embodiment of the present application in an actual scenario;

[0026] Fig.16 A schematic diagram of the structure of a brake distribution device provided in an embodiment of the present application;

[0027] Fig.17 A hardware entity diagram of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] The embodiment of the present application aims to provide a braking distribution method, which mainly solves the problem of reduced stability caused by the existing energy recovery system. The present application identifies the vehicle load state, combines the road (ramp) and environmental information (asphalt / ice / snow / rain, etc.), and dynamically calculates the front and rear axle adhesion limits in real time. On this basis, the front and rear electric braking are distributed based on the electric braking priority and front and rear axle stability limit principles, and the difference in torque required by the driver is supplemented by friction braking according to certain distribution rules, so that the vehicle can achieve a balance between energy recovery efficiency (improvement in cruising range) and stability. The technical solution of the present application is applicable to rear-wheel drive and four-wheel drive new energy vehicles.

[0029] Figure 1 The following is a schematic diagram of the implementation process of a braking allocation method provided in an embodiment of the present application. Figure 1 As shown, the method includes the following steps S101 to S103:

[0030] Step S101: Obtain vehicle load information.

[0031] In the embodiment of the present application, when the vehicle brakes, or in other words, the stability of the vehicle when braking is mainly affected by the following factors: the braking force required for vehicle braking, the maximum electric braking force and the maximum friction braking force that the vehicle can provide. When the sum of the maximum electric braking force and the maximum friction braking force that the vehicle can provide is greater than the braking force required for vehicle braking, the stability of the vehicle can be guaranteed. However, in actual situations, the sum of the maximum electric braking force and the maximum friction braking force that the vehicle can provide may often be less than the braking force required for vehicle braking. Therefore, in order to maximize the stability of the vehicle when using the energy recovery system, it is necessary to analyze and calculate the maximum electric braking force and the maximum friction braking force that the vehicle can provide and the braking force required for vehicle braking, so as to reasonably allocate the braking force required for vehicle braking according to actual conditions.

[0032] In the embodiment of the present application, the vehicle load information is used to calculate the sum of the maximum electric braking force and the maximum friction braking force that the vehicle can provide. The vehicle load information includes: the total weight of the vehicle, the dynamic front axle load of the vehicle, the dynamic rear axle load of the vehicle, the center of mass height of the vehicle, the wheelbase of the vehicle, the distance from the center of mass of the vehicle to the front axle, the distance from the center of mass of the vehicle to the rear axle, etc.

[0033] In some embodiments, the vehicle load information is estimated based on the load information of the vehicle when it is unloaded, combined with the actual situation of the vehicle carrying people and the slope of the ground on which the vehicle is located.

[0034] Step S102: determining the front and rear axle adhesion limits of the vehicle based on the vehicle load information and the environment information of the vehicle.

[0035] In the embodiment of the present application, the environmental information of the vehicle will affect the sum of the maximum electric braking force and the maximum friction braking force that the vehicle can provide. For example, when the same vehicle is driving on a dry asphalt road and a wet asphalt road, the sum of the maximum electric braking force and the maximum friction braking force that the vehicle can provide is different. The environmental information of the vehicle is mainly used to determine the road surface information on which the vehicle is driving, for example, whether there is snow on the road surface, whether the road surface is ice, whether the road surface is a cement surface or an asphalt surface, and whether the road surface is dry or wet.

[0036] In the embodiment of the present application, the front and rear axle adhesion limits of the vehicle are the sum of the maximum electric braking force and the maximum friction braking force that the vehicle can provide, including the front axle adhesion limit of the vehicle and the rear axle adhesion limit of the vehicle. The front axle adhesion limit of the vehicle is the sum of the maximum electric braking force and the maximum friction braking force that the front axle of the vehicle can provide. The rear axle adhesion limit of the vehicle is the sum of the maximum electric braking force and the maximum friction braking force that the rear axle of the vehicle can provide.

[0037] In the embodiment of the present application, the front and rear axle adhesion limits of the vehicle can be determined based on the vehicle load information and the environment information of the vehicle.

[0038] Step S103, in response to receiving a vehicle braking request carrying a target braking force, based on the motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits, using a braking distribution strategy to distribute the target braking force between the electric braking force and the friction braking force; wherein the distribution priority of the electric braking force in the braking distribution strategy is higher than the priority of the friction braking force, and the total braking force of the front and rear axles is not greater than the front and rear axle adhesion limits.

[0039] In an embodiment of the present application, the vehicle braking demand can be sent by the intelligent driving system, or obtained through the brake pedal travel sensor, the brake master cylinder pressure, the booster push rod travel sensor, or obtained through the gliding energy recovery after oil loss.

[0040] In the embodiment of the present application, the target braking force is the braking force required for the vehicle to brake, that is, the braking force required for the vehicle to brake. The braking force required by the vehicle corresponds to the braking torque or deceleration. The following mainly describes the braking force.

[0041] In the embodiment of the present application, the motor recovery capacity limit of the vehicle refers to the maximum electric braking force that the vehicle can provide. For a rear-wheel drive vehicle, the motor recovery capacity limit of the vehicle includes the rear motor recovery capacity limit, that is, the maximum rear axle electric braking force that the vehicle can provide; for a four-wheel drive vehicle, the motor recovery capacity limit of the vehicle includes the front motor recovery capacity limit and the rear motor recovery capacity limit, that is, the maximum front axle electric braking force that the vehicle can provide and the maximum rear axle electric braking force that the vehicle can provide.

[0042] In the embodiment of the present application, the distribution priority of the electric braking force in the distribution strategy is higher than the priority of the friction braking force in order to maximize the cruising range, that is, to obtain the recovered energy to the greatest extent, and the total braking force of the front and rear axles is not greater than the front and rear axle adhesion limit in order to ensure the stability of the vehicle.

[0043] In the embodiment of the present application, for a four-wheel drive vehicle, the target braking force is distributed to the electric braking force and the friction braking force using the braking distribution strategy, including: using the braking distribution strategy to distribute the target braking force to the front axle electric braking force, the rear axle electric braking force, the front axle friction braking force, and the rear axle friction braking force. For a rear-wheel drive vehicle, the target braking force is distributed to the electric braking force and the friction braking force using the distribution strategy, including: using the braking distribution strategy to distribute the target braking force to the rear axle electric braking force, the front axle friction braking force, and the rear axle friction braking force.

[0044] In an embodiment of the present application, when the target braking force, the motor recovery capacity limit, and the front and rear axle adhesion limits have different size relationships, the distribution strategy used when distributing the target braking force is also different, and the corresponding target braking force distribution results are also different.

[0045] In the embodiment of the present application, the general principle of braking force distribution is: on the basis of stability, electric braking force is given priority; the insufficient part of electric braking force is supplemented by friction braking force; when supplementing friction braking force, try to execute it on both the front and rear axles without destroying the stability boundary. Not destroying the stability boundary means: the total braking force of the front axle (the sum of the front axle electric braking force and the front axle friction braking force) is less than the front axle adhesion limit, and the total braking force of the rear axle (the rear axle electric braking force and the rear axle friction braking force) is less than the rear axle adhesion limit. Therefore, the approximate order of distribution is: the rear axle electric braking force, the front axle electric braking force, and the friction braking force are distributed in turn. The specific distribution order will change with the target braking force, the motor recovery capacity limit, and the relationship between the front and rear axle adhesion limits.

[0046] In the embodiment of the present application, there may be a situation where the target braking force is greater than the front and rear axle adhesion limit, that is, the braking force required for vehicle braking is greater than the sum of the maximum electric braking force and the maximum friction braking force that the vehicle can provide. In this case, the difference between the target braking force and the front and rear axle adhesion limit, that is, the braking force that exceeds the front and rear axle adhesion limit after sequential distribution, will be added to the front axle friction braking force and the rear axle friction braking force at the same time based on the front and rear friction braking force distribution ratio. The friction braking force can come from hydraulic brakes or from non-hydraulic brakes such as dry brake systems. For example, when the friction braking force comes from a hydraulic controller, the front and rear friction braking force distribution ratio is determined by formula (1), and when the friction braking force comes from a dry brake system, the front and rear friction braking force distribution ratio is determined by formula (2).

[0047]

[0048]

[0049] Among them, Df is the diameter of the front caliper wheel cylinder, Dr is the diameter of the rear caliper wheel cylinder, rf is the effective radius of the front brake disc, rr is the effective radius of the rear brake disc, uf is the friction coefficient of the front friction plate, ur is the friction coefficient of the rear friction plate, Rf is the front wheel rolling radius, and Rr is the rear wheel rolling radius. Among them, the above parameters can be obtained by query, among which, the β value represents the proportion of the friction braking force of the front axle, and the proportion of the friction braking force of the rear axle is 1-β.

[0050] In the embodiment of the present application, the vehicle load information of the vehicle is obtained; based on the vehicle load information and the environment information of the vehicle, the front and rear axle adhesion limits of the vehicle are determined; in response to receiving a vehicle braking request carrying a target braking force, based on the motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits, the target braking force is brake-distributed between the electric braking force and the friction braking force using a braking distribution strategy; wherein the distribution priority of the electric braking force in the braking distribution strategy is higher than the priority of the friction braking force, and the total braking force of the front and rear axles is not greater than the front and rear axle adhesion limits. Based on the principle of stability priority, the electric braking force is given priority, and the remaining braking force is distributed to the friction braking force without destroying the stability boundary. In this way, a balance can be achieved in energy recovery efficiency and stability, and the stability of the vehicle can be guaranteed to the maximum extent.

[0051] Figure 2 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Figure 2 As shown, based on Figure 1 , Figure 1 S102 in can be updated to S201 to S202, which will be combined Figure 2 The steps shown are explained.

[0052] Step S201: Calculate the front and rear dynamic axle loads based on the vehicle load information and the braking force data of the vehicle.

[0053] In the embodiment of the present application, the braking force data of the vehicle refers to the current total front and rear braking force data of the vehicle, including the front axle friction braking force, the rear axle friction braking force, the front axle electric braking force and the rear axle electric braking force. Among them, the front axle friction braking force and the rear axle friction braking force can be obtained through the power system controller, and the front axle electric braking force and the rear axle electric braking force can be obtained through the anti-lock braking system.

[0054] In the embodiment of the present application, the front and rear dynamic axle load refers to the axle load distribution of the vehicle mass on the front and rear axles when the vehicle is in motion. Here, it mainly refers to the axle load distribution of the vehicle mass on the front and rear axles during the braking process. The front and rear dynamic axle loads include the front axle dynamic load and the rear axle dynamic load. During the braking process of the vehicle, the inertial force acting at the center of mass position will change the front and rear axle loads of the vehicle, thereby changing the adhesion between the front and rear axles and the ground, affecting the braking performance of the vehicle.

[0055] In the embodiment of the present application, the front and rear dynamic axle loads will affect the front and rear axle adhesion limits of the vehicle. The front and rear dynamic axle loads are calculated based on the vehicle load information and the vehicle braking force data.

[0056] In an embodiment of the present application, the total braking force data of the vehicle is collected in real time, the real-time front and rear axle adhesion limits are determined based on the total braking force data and vehicle load information, and the allocation strategy is updated in real time to ensure the stability of the vehicle.

[0057] Step S202: determining the front and rear axle adhesion limits of the vehicle based on the front and rear dynamic axle loads and the environmental information.

[0058] In the embodiment of the present application, environmental information affects the adhesion coefficient of the road surface and the vehicle. The adhesion coefficient of the vehicle is the ratio of the adhesion force to the normal pressure of the wheel (the direction perpendicular to the road surface). In rough calculation, it can be regarded as the static friction coefficient between the tire and the road surface. It is determined by the road surface and the tire. The larger this coefficient is, the greater the available adhesion is, and the less likely the car is to slip. When the car brakes, the braking force of the wheel is related to the ground adhesion coefficient.

[0059] In the embodiment of the present application, environmental information directly affects the front and rear axle adhesion limits of the vehicle. Therefore, the front and rear axle adhesion limits of the vehicle can be determined based on the front and rear dynamic axle loads and environmental information. It should be noted here that the front axle adhesion limit of the vehicle is determined based on the front axle dynamic axle load and environmental information, and the rear axle adhesion limit of the vehicle is determined based on the rear axle dynamic axle load and environmental information.

[0060] Through the above steps, the dynamic loads of the front and rear axles are calculated based on the vehicle load information and the braking force data of the vehicle; the front and rear axle adhesion limits of the vehicle are determined based on the front and rear axle dynamic loads and the environmental information. By acquiring the vehicle's braking force data, vehicle load information, and environmental information in real time, the braking distribution strategy can be updated in real time according to the front and rear adhesion limits of the vehicle, and then the vehicle can be controlled in real time to further ensure its stability during braking.

[0061] Figure 3 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Figure 3 As shown, based on Figure 2 The vehicle load information includes: vehicle weight, vehicle wheelbase information and vehicle front and rear roller radius, Figure 2 Step S201 in can be updated to S301 to S303, combining Figure 3 The steps shown are explained.

[0062] Step S301: Determine the deceleration generated by the braking force based on the braking force data, the vehicle weight, and the front and rear roller radii of the vehicle.

[0063] In the embodiment of the present application, the vehicle weight refers to the current total weight of the vehicle, including the empty weight of the vehicle and the weight of the loaded passengers. The front and rear rolling wheel radius of the vehicle refers to the equivalent radius used to calculate when the front and rear wheels roll, and the circumference used to calculate is equal to the actual rolling distance of the wheel. This parameter can be directly obtained by the power system controller.

[0064] In the embodiment of the present application, the deceleration generated by the braking force refers to the deceleration generated by the total braking force of the front and rear of the vehicle. Here, the direction of the deceleration generated by the braking force is opposite to the direction of the vehicle's travel. Formula (3) is used to calculate the deceleration.

[0065] Ax_brk=((Fuf+EBf) / Rf+(Fur+EBr) / Rr) / G Formula (3)

[0066] Among them, Ax_brk is the deceleration generated by the braking force, Fuf is the front axle friction braking force, EBf is the front axle electric braking force, Rf is the front wheel rolling radius, Fur is the rear axle friction braking force, EBr is the rear axle electric braking force, Rr is the rear wheel rolling radius, and G is the weight of the vehicle.

[0067] Step S302: Determine the uphill and downhill type of the vehicle and the corresponding slope information based on the acquired actual deceleration and the deceleration generated by the braking force.

[0068] In the embodiment of the present application, the actual deceleration is the deceleration measured by the inertial sensor. The actual deceleration and the deceleration caused by the braking force may be different or the same. When the vehicle is traveling on a horizontal road, the deceleration caused by the braking force is the same as the actual deceleration, ignoring the error; when the vehicle brakes downhill, the deceleration caused by the braking force is greater than the actual deceleration; when the vehicle brakes uphill, the deceleration caused by the braking force is less than the actual deceleration. The slope information of the vehicle can be confirmed based on the actual deceleration and the deceleration caused by the braking force. The calculation formula for the slope information is formula (4).

[0069] θ=arcsin(Ax_IMU-Ax_brk) Formula (4)

[0070] Among them, θ is the slope information. When it is positive, it indicates that the vehicle is braking downhill; when it is negative, it indicates that the vehicle is braking uphill. Its unit is radian. Ax_IMU is the actual deceleration, and Ax_brk is the deceleration caused by the braking force. In this calculation, the actual deceleration and the deceleration caused by the braking force are both taken as absolute values, and the unit is m / s 2 .

[0071] In the embodiment of the present application, by calculating the actual deceleration and the deceleration generated by the braking force, it is possible to determine whether the braking type is uphill braking or downhill braking, and the slope information, i.e., the slope value, can be obtained. The type of uphill and downhill can be determined by the positive or negative of the slope information.

[0072] Step S303, determining the front and rear dynamic axle loads by using the dynamic axle load calculation strategy corresponding to the uphill and downhill types, the slope information, the deceleration generated by the braking force, the vehicle weight and the vehicle wheelbase related information.

[0073] In the embodiment of the present application, the dynamic axle load calculation strategy corresponds to the uphill and downhill types. Uphill and downhill types correspond to different dynamic axle load calculation strategies. The front and rear dynamic axle loads include the front axle dynamic axle load and the rear axle dynamic axle load. The dynamic axle load calculation strategy includes the front axle dynamic axle load calculation and the rear axle load calculation.

[0074] In the embodiment of the present application, the vehicle wheelbase related information includes: the center of mass height, the distance from the center of mass to the front axle, and the distance from the center of mass to the rear axle; wherein the center of mass height refers to the position of the center of gravity of the vehicle, the distance from the center of mass to the front axle refers to the horizontal distance from the center of mass of the vehicle to the front axle, and the distance from the center of mass to the rear axle refers to the horizontal distance from the center of mass of the vehicle to the rear axle. The vehicle wheelbase refers to the distance from the center of the front axle to the center of the rear axle of the vehicle. The above parameters can all be obtained by calculation.

[0075] In the embodiment of the present application, the dynamic load of the front axle corresponding to downhill braking is calculated as shown in formula (5), and the dynamic load of the rear axle corresponding to downhill braking is calculated as shown in formula (6). The dynamic load of the front axle corresponding to uphill braking is calculated as shown in formula (7), and the dynamic load of the rear axle corresponding to uphill braking is calculated as shown in formula (8).

[0076] Fzf=(G*Ax_brk*h+G*sinθ*h+G*cosθ*b) / L (5)

[0077] Fzr=(G*cosθ*aG*Ax_brk*hG*sinθ*h) / L (6)

[0078] Fzf=(G*Ax_brk*hG*sinθ*h+G*cosθ*b) / L (7)

[0079] Fzr=(G*cosθ*aG*Ax_brk*h+G*sinθ*h) / L (8)

[0080] Among them, Fzf is the dynamic load on the front axle, Fzr is the dynamic load on the rear axle, G is the weight of the vehicle, Ax_brk is the deceleration caused by the braking force, θ is the slope information, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, and L is the vehicle wheelbase.

[0081] Through the above steps, the deceleration generated by the braking force is determined based on the braking force data, the vehicle weight and the front and rear roller radius of the vehicle; the uphill and downhill type of the vehicle and the corresponding slope information are determined based on the actual deceleration obtained and the deceleration generated by the braking force; the dynamic loads of the front and rear axles are determined using the dynamic axle load calculation strategy corresponding to the uphill and downhill type, the slope information, the deceleration generated by the braking torque, the vehicle weight and the vehicle wheelbase related information. Calculating the dynamic axle load of the front axle in this way makes the front and rear axle adhesion limits obtained based on the front and rear dynamic axle loads more accurate, and further makes the allocation strategy obtained based on the front and rear axle adhesion limits more accurate, ensuring the stability of the vehicle.

[0082] Figure 4 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Figure 4 As shown, based on Figure 2 , Figure 2 Step S202 can be updated to S401 to S402, combining Figure 4 The steps shown are explained.

[0083] Step S401: Determine the road type of the road on which the vehicle is traveling based on the environmental information.

[0084] In the embodiment of the present application, the environmental information includes rainy days, sunny days, snowy days, environmental temperature information, etc. The road surface types include: dry asphalt, wet asphalt, dry cement, wet cement, snow surface, and ice surface. The environmental information is used to determine the road surface type on which the vehicle is traveling.

[0085] Step S402: Determine the front and rear axle adhesion limits of the vehicle based on the road surface type and the front and rear dynamic axle loads.

[0086] In the embodiment of the present application, different road surface types correspond to different road surface adhesion coefficients; that is, the road surface type affects the front and rear adhesion limits of the vehicle. The front and rear dynamic axle loads also affect the front and rear adhesion limits of the vehicle. Therefore, the front and rear adhesion limits can be determined by the road surface type and the front and rear dynamic axle loads.

[0087] Through the above steps, the road type of the road on which the vehicle is traveling is determined based on the environmental information, and the front and rear axle adhesion limits of the vehicle are determined based on the road type and the front and rear dynamic axle loads. In this way, the determined front and rear axle adhesion limits can be made more accurate, thereby making the braking distribution strategy determined based on the front and rear axle adhesion limits more accurate.

[0088] Figure 5 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Figure 5 As shown, based on Figure 4, Figure 4 Step S401 can be updated to S501 and S502, combining Figure 5 The steps shown are explained.

[0089] Step S501: Acquire a road surface image captured by an image sensor, and analyze the road surface image to obtain the road surface type.

[0090] In an embodiment of the present application, the road surface type can be obtained by analyzing the road surface image. The road surface image is collected in real time by an image sensor. The image sensor can be a camera of an intelligent driving system. The acquired road surface image can be analyzed after filtering and noise reduction processing, which will make the result of the road surface type obtained by analysis more accurate.

[0091] Step S502, obtaining other environmental signals other than those collected by the image sensor signal, and determining the road surface type based on the other environmental signals; the other environmental signals include at least one of the following: a vehicle wiper switch signal, a rain sensor signal, and temperature.

[0092] In an embodiment of the present application, the road surface type can also be determined by other environmental signals. Other environmental signals may be vehicle-mounted wiper signals, rain sensor signals, and temperature. Other environmental signals may be acquired in real time by non-image sensors, such as wiper switch sensors, rain sensors, and temperature sensors. Exemplarily, the road surface type can be determined to be wet asphalt or wet cement by the vehicle-mounted wiper signal or rain sensor signal. The road is set to dry asphalt road by default, which is wet asphalt when it rains and dry asphalt when it does not rain. Exemplarily, the ambient temperature data is acquired by the vehicle-mounted ambient temperature sensor, and the road surface type is directly set to snow surface when the ambient temperature is lower than X°C (such as 0°C).

[0093] In an embodiment of the present application, the road surface type is acquired in real time by an image sensor or a non-image sensor, so that the acquired road surface adhesion coefficient is more accurate, the front and rear axle adhesion limits determined based on the road surface type are more accurate, and further, the braking distribution strategy determined based on the front and rear axle adhesion limits is more accurate.

[0094] Figure 6 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Figure 6 As shown, based on Figure 4 , Figure 4 The S402 can be updated to S601 and S602, which will be combined Figure 6 The steps shown are explained.

[0095] Step S601: using a preset mapping relationship between a road surface type and a road surface adhesion coefficient, determine a target road surface adhesion coefficient corresponding to the road surface type.

[0096] In the embodiment of the present application, there is a mapping relationship between the road surface type and the road surface adhesion coefficient, and the target road surface adhesion coefficient corresponding to the road surface type can be determined based on the preset mapping relationship. For example, the road surface adhesion coefficient corresponding to dry asphalt is 1, the road surface adhesion coefficient corresponding to wet asphalt is 0.4, the road surface adhesion coefficient corresponding to dry cement is 0.8, the road surface adhesion coefficient corresponding to wet cement is 0.45, the road surface adhesion coefficient corresponding to snow surface is 0.3, and the road surface adhesion coefficient corresponding to ice surface is 0.1.

[0097] In the embodiment of the present application, once the road type is obtained, the corresponding road adhesion coefficient can be determined through a preset mapping relationship. The road adhesion coefficient can be modified according to the driver's experience.

[0098] Step S602: generating the front and rear axle adhesion limits based on the target road adhesion coefficient, the front and rear dynamic axle loads and a preset safety factor.

[0099] In the embodiment of the present application, the preset safety factor includes a preset front axle safety factor and a preset rear axle safety factor. The preset safety factor ranges from 0 to 1.

[0100] In the embodiment of the present application, the front and rear axle adhesion limits include the front axle adhesion limit and the rear axle adhesion limit, wherein the front axle adhesion limit is calculated as shown in formula (9); and the rear axle adhesion limit is calculated as shown in formula (10).

[0101]

[0102]

[0103] Where Φf is the front axle adhesion limit, Fzf is the front axle dynamic load, is the target road adhesion coefficient, x1 is the front axle safety factor; Φr is the rear axle adhesion limit, Fzr is the rear axle dynamic axle load, and x2 is the rear axle safety factor.

[0104] Through the above steps, the target road adhesion coefficient corresponding to the road type is determined by using the mapping relationship between the preset road type and the road adhesion coefficient, and the front and rear axle adhesion limits are generated based on the target road adhesion coefficient, the front and rear dynamic axle loads and the preset safety factor. In this way, the calculated front and rear axle adhesion limits can be made more accurate, the obtained braking distribution strategy can be made more accurate, and the stability of the vehicle can be further guaranteed.

[0105] Figure 7 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Figure 3As shown, the vehicle wheelbase related information includes: vehicle wheelbase, center of mass height and distance between center of mass and front and rear axles, based on Figure 3 , Figure 3 The S101 can be updated to S701 and S706, which will be combined Figure 7 The steps shown are explained.

[0106] Step S701, obtaining the preset vehicle wheelbase, center of mass height, and front and rear roller radii of the vehicle.

[0107] In the embodiment of the present application, the vehicle wheelbase refers to the distance from the center of the front axle to the center of the rear axle of the vehicle. The center of mass height refers to the location of the center of gravity of the vehicle. The front and rear rolling wheel radius of the vehicle refers to the equivalent radius used to calculate when the front and rear wheels roll, and the circumference used to calculate is equal to the actual rolling distance of the wheel. The above parameters can be directly obtained.

[0108] Step S702: When the vehicle's parking slope is greater than the maximum set slope, the initial vehicle weight of the vehicle is used as the vehicle weight, and the initial distance between the vehicle's center of mass and the front and rear axles is used as the distance between the center of mass and the front and rear axles.

[0109] In the embodiment of the present application, the vehicle's parking slope is the slope information obtained by the vehicle-mounted inertial sensor when the vehicle is parked on the slope, which is the slope information when all doors are closed and the vehicle is not started after power is turned on. The parking slope is generally expressed as a percentage, that is, the ratio of the height of the slope to the horizontal distance of the slope. The maximum set slope is generally set to 8%, that is, the ratio of the height of the slope to the horizontal distance of the slope is 8%.

[0110] In the embodiment of the present application, the initial vehicle weight of the vehicle refers to the vehicle weight in the unloaded state; the initial distance between the center of mass of the vehicle and the front and rear axles refers to the distance between the center of mass of the vehicle and the front and rear axles in the unloaded state. When the vehicle is parked on a slope with a slope gradient greater than the maximum set slope, the initial vehicle weight of the vehicle is directly used as the vehicle weight in calculating the front and rear dynamic axle loads, and the initial distance between the center of mass of the vehicle and the front and rear axles is used as the distance between the center of mass of the vehicle and the front and rear axles in calculating the front and rear dynamic axle loads.

[0111] Step S703: When the vehicle parking slope is less than or equal to the maximum set slope, determine the vehicle weight based on the initial vehicle weight and the number of passengers.

[0112] In an embodiment of the present application, when the vehicle's parking slope is less than or equal to the maximum set slope, it is necessary to redetermine the vehicle weight and the distance between the center of mass and the front and rear axles used to calculate the front and rear dynamic axle loads in combination with the vehicle's passenger conditions.

[0113] In the embodiment of the present application, the number of passengers can be obtained through the seat belt signal of each seat, or directly obtained through the camera in the vehicle. For example, the weight of one passenger is assumed to be 75 kg, so the total weight corresponding to the number of passengers can be approximately obtained. In some embodiments, the sum of the initial vehicle weight and the total weight corresponding to the number of passengers can be directly used as the vehicle weight.

[0114] Step S704: Determine the static front and rear axle loads based on the initial axle load parameters and axle load increment parameters of the vehicle.

[0115] In an embodiment of the present application, the initial axle load parameters may be the initial front axle load and the initial rear axle load; the above parameters may be directly obtained. The axle load increment parameters corresponding to the initial front axle load and the initial rear axle load may be obtained through the number of passengers, specifically in the following two ways. The first: directly obtain the distribution of passengers through the in-car camera, and use the weight of the passengers sitting in the front row as the front axle load increment, and use the weight of the passengers sitting in the back row as the rear axle load increment. The second: determine the front axle load increment and the rear axle load increment based on the front and rear axle load data corresponding to different numbers of passengers, that is, different numbers of passengers correspond to different front axle load increments and rear axle load increments; illustratively, for each additional passenger, the front axle load increment is m1, and the rear axle load increment is m2.

[0116] In the embodiment of the present application, the initial axle load parameter may also be the initial wheel load, including the initial left front wheel load, the initial right front wheel load, the initial left rear wheel load and the initial right rear wheel load. Here, the left front wheel load, the right front wheel load and the front axle load correspond; the left rear wheel load and the right rear wheel load correspond to the rear axle load. The axle load increase corresponding to the initial wheel load is the single-wheel wheel load increment, and the single-wheel wheel load increment can be obtained through the air spring stiffness information. Specifically, the air spring controller provides air pressure data for the four-wheel air springs, which is the air pressure when the air spring adjusts the body posture into place after the occupant gets on the vehicle, and then the air spring stiffness of each wheel is obtained by consulting the known "air pressure-stiffness" curve of the air spring, and compared with the design stiffness in the no-load state (also obtained by looking up the air pressure of the air spring), the single-wheel wheel load increment under the manned state of each wheel is obtained; the left and right wheel loads are averaged to obtain the axle load of the single axle. That is to say, the front axle load increment may be the average value of the wheel load increments of the left front wheel and the right front wheel corresponding to the front axle; the rear axle load increment may be the average value of the wheel load increments of the left rear wheel and the right rear wheel corresponding to the rear axle.

[0117] In the embodiment of the present application, the static front and rear axle loads refer to the front and rear axle loads in a stationary state. The static front and rear axle loads include the static front axle load and the static rear axle load. Among them, the static front axle load is the sum of the initial front axle load and the front axle load increment, and the static rear axle load is the sum of the initial rear axle load and the rear axle load increment.

[0118] Step S705: Determine the distance between the center of mass and the front and rear axles based on the vehicle weight, the static front and rear axle loads and the vehicle wheelbase.

[0119] In the embodiment of the present application, the distance between the center of mass and the front and rear axles includes the distance between the center of mass and the front axle and the distance between the center of mass and the rear axle. The distance between the center of mass and the front axle is calculated as shown in formula (11), and the distance between the center of mass and the rear axle is calculated as shown in formula (12).

[0120] a=Gr / G*L Formula (11)

[0121] b=Gf / G*L Formula (12)

[0122] Among them, a is the distance from the center of mass to the front axle, Gr is the static rear axle load, G is the vehicle weight, L is the vehicle wheelbase, b is the distance from the center of mass to the rear axle, and Gf is the static front axle load.

[0123] Step S706: Use the vehicle wheelbase, the center of mass height, the vehicle weight and the distance between the center of mass and the front and rear axles as vehicle load information.

[0124] Among them, the vehicle wheelbase, the center of mass height and the distance between the center of mass and the front and rear axles are also referred to as vehicle wheelbase related information.

[0125] In an embodiment of the present application, the vehicle wheelbase, center of mass height, vehicle weight and distance from the center of mass to the front and rear axles obtained in the above steps are used as vehicle load information for subsequent calculations.

[0126] Among them, the vehicle wheelbase / center height and the distance between the center of mass and the front and rear axles in the vehicle load information can also be used to obtain relevant information about the vehicle wheelbase. Among them, the vehicle wheelbase related information can be used to calculate the front and rear dynamic axle loads.

[0127] Through the above steps, it is determined whether to correct the vehicle weight and the front and rear static axle loads according to the vehicle's slope information, so that the front and rear adhesion limits calculated based on the above parameters can be more accurate, thereby making the braking distribution strategy more accurate and ensuring the stability of the vehicle to the greatest extent.

[0128] Figure 8 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Figure 8 As shown, the front and rear axle adhesion limits include the rear axle adhesion limit, and the motor recovery capability limit includes the rear motor recovery capability limit. Figure 1 , Figure 1 The S103 can be updated to S801, which will combine Figure 8 The steps shown are explained.

[0129] Step S801: when the target braking force is less than the minimum value between the rear motor recovery capacity limit and the rear axle adhesion limit, allocate a rear axle electric braking force having a magnitude equal to the target braking force.

[0130] In the embodiment of the present application, when the target braking force is less than the minimum value between the rear motor recovery capacity limit and the rear axle adhesion limit, it indicates that the electric braking force that can be performed by the rear axle is greater than the target braking force, and the sum of the electric braking force and the friction braking force that can be performed by the rear axle is greater than the target braking force. That is, the braking force required for vehicle braking will not affect the stability of the vehicle. At this time, the target braking force is allocated to the rear axle, and the rear axle electric braking force equal to the target braking force is directly allocated.

[0131] Through the above steps, when the target braking force is less than the minimum value between the rear motor recovery capacity limit and the rear axle adhesion limit, the rear axle electric braking force with a magnitude of the target braking force is executed, which can improve the cruising range.

[0132] Fig. 9 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Fig. 9 As shown, the front and rear axle adhesion limits include the front axle adhesion limit and the rear axle adhesion limit, and the motor recovery capability limit includes the front motor recovery capability limit and the rear motor recovery capability limit. Figure 1 , Figure 1 The S103 can be updated to S901 to S902, which will be combined Fig. 9 The steps shown are explained.

[0133] Step S901, when the target braking force is greater than the rear axle adhesion limit, and the target braking force is less than or equal to the rear motor recovery capacity limit, the target braking force is allocated in the order of rear axle electric braking force, front axle electric braking force and front axle friction braking force; wherein the rear axle electric braking force is the rear axle adhesion limit, when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit and the front axle adhesion limit, and the sum of the front axle friction braking force and the front axle electric braking force is less than or equal to the front axle adhesion limit; when the vehicle is a rear-wheel drive vehicle, the front axle friction braking force is less than or equal to the front axle adhesion limit.

[0134] In the embodiment of the present application, when the target braking force is greater than the rear axle adhesion limit, and the target braking force is less than or equal to the rear motor recovery capacity limit, the braking force equal to the rear axle adhesion limit can be first allocated to the rear axle electric braking force. At this time, the rear axle is already at the stability boundary, so the remaining braking force is recorded as the first remaining part and is preferentially allocated to the front axle. The allocation is based on the vehicle's drive type, and the specific allocation rules are as follows:

[0135] When the first remaining part is less than or equal to the front axle adhesion limit: For rear-wheel drive vehicles, there is no front axle electric braking force, so the remaining braking force is allocated to the front axle friction braking force until the front axle friction braking force reaches the front axle adhesion limit. In this process, the stability boundary of the front axle is not destroyed. For four-wheel drive vehicles, the front axle electric braking force and the front axle friction braking force are allocated in the order of allocation.

[0136] When the first remaining part is greater than the front axle adhesion limit: for rear-wheel drive vehicles, the front axle friction braking force is allocated to the size of the front axle adhesion limit; for four-wheel drive vehicles, the front axle electric braking force and the front axle friction braking force are allocated in this order until the sum of the two reaches the front axle adhesion limit.

[0137] Step S902: When there is excess braking force after sequential distribution, the excess braking force is supplementarily distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0138] In the embodiment of the present application, when the first remaining part is greater than the front axle adhesion limit, after being distributed in the above manner, there will be excess braking force, which is the difference between the target braking force and the front and rear axle adhesion limits.

[0139] In the embodiment of the present application, the excess braking force is distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0140] Through the above steps, a balance can be achieved between cruising range and stability, that is, the cruising range is maximized while ensuring stability first. When the target braking force exceeds the front and rear axle adhesion limit, the excess portion is distributed based on the preset front and rear friction braking force distribution ratio, which can maximize the stability of the vehicle.

[0141] Fig.10 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Fig.10 As shown, the front and rear axle adhesion limits include the front axle adhesion limit and the rear axle adhesion limit, and the motor recovery capability limit includes the front motor recovery capability limit and the rear motor recovery capability limit. Figure 1 , Figure 1 The S103 can be updated to S1001, which will combine Fig.10 The steps shown are explained.

[0142] Step S1001, when the target braking force is greater than the rear motor recovery capacity limit and the target braking force is less than or equal to the rear axle adhesion limit, the target braking force is distributed in the order of rear axle electric braking force, front axle electric braking force and friction braking force; wherein the rear axle electric braking force is the rear motor recovery capacity limit, and when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit; the front axle friction braking force and the rear axle friction braking force in the friction braking force are obtained by distributing the remaining braking force based on a preset front and rear friction braking force distribution ratio.

[0143] In the embodiment of the present application, when the target braking force is greater than the rear motor recovery capacity limit and the target braking force is less than or equal to the rear axle adhesion limit, the braking force equal to the rear motor recovery capacity limit can be first allocated to the rear axle electric braking force. After the rear axle electric braking force is allocated, the difference between the target braking force and the rear motor recovery capacity limit is recorded as the first remaining part, and then allocated according to the following rules based on the vehicle drive type:

[0144] For a rear-wheel drive vehicle, the first remaining portion is directly distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0145] For four-wheel drive vehicles, when the first remaining part is greater than the front motor recovery capacity limit, the braking force equal to the front motor recovery capacity limit is first allocated to the front axle electric braking force; the difference between the first remaining part and the front motor recovery capacity limit is used as the second remaining part, and the second remaining part is allocated to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force allocation ratio.

[0146] For a four-wheel drive vehicle, when the first remaining portion is smaller than the front motor recovery capacity limit, the first remaining portion is directly allocated to the front axle electric braking.

[0147] Through the above steps, the cruising range can be maximized while ensuring stability first.

[0148] Fig.11 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Fig.11 As shown, the front and rear axle adhesion limits include the front axle adhesion limit and the rear axle adhesion limit, and the motor recovery capability limit includes the front motor recovery capability limit and the rear motor recovery capability limit. Figure 1 , Figure 1 The S103 can be updated to S1101 to S1102, which will be combined Fig.11 The steps shown are explained.

[0149] Step S1101, when the target braking force is greater than the rear axle adhesion limit, and the rear axle adhesion limit is greater than or equal to the rear motor recovery capacity limit, the target braking force is distributed in the order of rear axle electric braking force, front axle electric braking force and friction braking force; wherein, the rear axle electric braking force is the rear motor recovery capacity limit, and when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit and the front axle adhesion limit; the distribution process of the front axle friction braking force and the rear axle friction braking force in the friction braking force includes: distributing the remaining braking force based on a preset front and rear friction braking force distribution ratio until the front axle friction braking force reaches the front axle adhesion limit or the rear axle friction braking force reaches the rear axle adhesion limit, and adjusting the friction braking force of the target axle that has not reached the adhesion limit to the adhesion limit of the target axle.

[0150] In the embodiment of the present application, when the target braking force is greater than the rear axle adhesion limit, and the rear axle adhesion limit is greater than or equal to the rear motor recovery capability limit, the braking force equal to the rear motor recovery capability limit is allocated to the rear axle electric braking force, and the difference between the target braking force and the rear motor recovery capability limit is recorded as the first remaining part. Based on the drive type of the vehicle, the first remaining part is allocated according to the following rules:

[0151] For rear-wheel drive vehicles, the first remaining part is distributed to the front axle friction braking force and the rear axle friction braking force based on the preset front-rear friction braking force distribution ratio. During the execution process, it is ensured that the sum of the rear axle electric braking force and the rear axle friction braking force is less than or equal to the rear axle adhesion limit, and that the front axle friction braking force is less than or equal to the front axle adhesion limit. In this process, when the rear axle electric braking force and the rear axle friction braking force first reach the rear axle adhesion limit, the total braking force of the rear axle is kept unchanged, and the braking force continues to be distributed to the front axle friction braking force until the front axle reaches the front axle adhesion limit; when the front axle friction braking force first reaches the front axle adhesion limit, the friction braking force of the front axle is kept unchanged, and the braking force continues to be distributed to the rear axle friction braking force until the rear axle reaches the rear axle adhesion limit.

[0152] For a four-wheel drive vehicle, when the first remaining portion is smaller than the front motor recovery capability limit, and the front motor recovery capability limit is smaller than the front axle adhesion limit, the first remaining portion is entirely allocated to the front axle electric braking force.

[0153] For a four-wheel drive vehicle, when the first remaining portion is greater than the front axle adhesion limit, and the front axle adhesion limit is greater than or equal to the front motor recovery capacity limit, the braking force equal to the front motor recovery capacity limit is first allocated to the front axle electric brake, and the difference between the first remaining portion and the front motor recovery capacity limit is recorded as the second remaining portion. The second remaining portion is allocated to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force allocation ratio. During the execution process, it is ensured that the sum of the rear axle electric braking force and the rear axle friction braking force is less than or equal to the rear axle adhesion limit, and it is ensured that the sum of the front axle electric braking force and the front axle friction braking force is less than or equal to the front axle adhesion limit. During this process, when the sum of the rear axle electric braking force and the rear axle friction braking force reaches the rear axle adhesion limit first, the total braking force of the rear axle is kept unchanged, and the braking force continues to be allocated to the front axle friction braking force until the front axle reaches the front axle adhesion limit; when the sum of the front axle electric braking force and the front axle friction braking force reaches the front axle adhesion limit first, the friction braking force of the front axle is kept unchanged, and the braking force continues to be allocated to the rear axle friction braking force until the rear axle reaches the rear axle adhesion limit.

[0154] For four-wheel drive vehicles, when the first remaining part is greater than the front motor recovery capacity limit, and the front motor recovery capacity limit is greater than the front axle adhesion limit, first allocate a braking force equal to the front axle adhesion limit to the front axle electric braking force; the difference between the first remaining part and the front axle adhesion limit is recorded as the third remaining part. The third remaining part is allocated to the rear axle friction braking force, and in this process, the sum of the rear axle electric braking force and the rear axle friction braking force is ensured to be less than or equal to the rear axle adhesion limit.

[0155] Step S1102: When there is excess braking force after sequential distribution, the excess braking force is supplementarily distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0156] In the embodiment of the present application, after the above-mentioned distribution, when the sum of the rear axle friction braking force and the rear axle electric braking force is equal to the rear axle adhesion limit, and the sum of the front axle friction braking force and the front axle electric braking force is equal to the front axle adhesion limit, there is still a remainder of the target braking force, then the remainder is the excess braking force.

[0157] In the embodiment of the present application, the excess braking force is distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0158] Through the above steps, a balance can be achieved between cruising range and stability, that is, the cruising range is maximized while ensuring stability first. When the target braking force exceeds the front and rear axle adhesion limit, the excess portion is distributed based on the preset front and rear friction braking force distribution ratio, which can maximize the stability of the vehicle.

[0159] Fig.12 FIG. 1 is a schematic diagram of a process flow of implementing a braking allocation method provided in an embodiment of the present application. Fig.12 As shown, the front and rear axle adhesion limits include the front axle adhesion limit and the rear axle adhesion limit, and the motor recovery capability limit includes the front motor recovery capability limit and the rear motor recovery capability limit. Figure 1 , Figure 1 The S103 can be updated to S1201 to S1202, which will be combined Fig.12 The steps shown are explained.

[0160] Step S1201, when the target braking force is greater than the rear motor recovery capacity limit, and the rear motor recovery capacity limit is greater than the rear axle adhesion limit, the target braking force is distributed in the order of rear axle electric braking force, front axle electric braking force and friction braking force; wherein the rear axle electric braking force is the rear axle adhesion limit, and when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit and the front axle adhesion limit.

[0161] In the embodiment of the present application, when the target braking force is greater than the rear motor recovery capacity limit, and the rear motor recovery capacity limit is greater than the rear axle adhesion limit, the braking force equal to the rear axle adhesion limit is first allocated to the rear axle electric brake; the difference between the target braking force and the rear axle adhesion limit is recorded as the first remaining part, and the first remaining part is allocated according to the following allocation rules based on the defect type:

[0162] For rear-wheel drive vehicles, the first remaining part is first allocated to the front axle friction braking force until the front axle friction braking force reaches the front axle adhesion limit.

[0163] For a four-wheel drive vehicle, when the first remaining portion is smaller than the front motor recovery capability limit, and the front motor recovery capability limit is smaller than the front axle adhesion limit, the first remaining portion is allocated to the front axle electric braking force.

[0164] For four-wheel drive vehicles, when the first remaining part is greater than the front axle adhesion limit, and the front axle adhesion limit is greater than or equal to the front motor recovery capacity limit, the braking force equal to the front motor recovery capacity limit is allocated to the front axle electric braking force; the difference between the first remaining part and the front motor recovery capacity limit is recorded as the second remaining part; and the second remaining part is allocated to the front axle friction braking force until the front axle electric braking force and the front axle friction braking force reach the front axle adhesion limit.

[0165] For a four-wheel drive vehicle, when the first remaining portion is greater than the front motor recovery capability limit, and the front motor recovery capability limit is greater than the front axle adhesion limit, a braking force equal to the front axle adhesion limit is allocated to the front axle electric braking force.

[0166] Step S1202: When there is excess braking force after sequential distribution, the excess braking force is supplementarily distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0167] In the embodiment of the present application, after the above distribution, when the rear axle electric brake reaches the rear axle adhesion limit, and the front axle electric brake and the front axle friction brake reach the front axle adhesion limit, if there is still a remainder of the target braking force, then the remainder is the excess braking force.

[0168] In the embodiment of the present application, the excess braking force is distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0169] Through the above steps, a balance can be achieved between cruising range and stability, that is, the cruising range is maximized while ensuring stability first. When the target braking force exceeds the front and rear axle adhesion limit, the excess portion is distributed based on the preset front and rear friction braking force distribution ratio, which can maximize the stability of the vehicle.

[0170] The following is an application of a braking distribution method provided by an embodiment of the present application in a practical scenario, and the method can be implemented by the following steps. Fig.13 and Fig.14 The present application embodiment relates to a brake distribution control system, such as Fig.13 , mainly composed of a braking demand calculation module 1301, an adhesion limit calculation module 1302, and a braking force distribution module 1303. In addition to the above three main modules, the vehicle wiper / air suspension / ambient temperature sensor / seat belt system / inertial sensor / ADAS system / brake pedal travel sensor and other modules are also required to provide information such as rainy days / road conditions (dry asphalt / wet asphalt / snow / ice, etc.) / slopes / member information / vehicle load / ambient temperature, etc. The execution end needs the power system (energy recovery) and the friction brake system to cooperate. The overall logical framework of the system is shown in Fig.14 .

[0171] Step 1, obtain the braking target. The braking target can be obtained through the braking demand calculation module 1301. The braking target can come from the brake pedal travel sensor 1401 when the driver steps on the brake (for example, through the brake pedal travel sensor, brake master cylinder pressure, booster push rod travel sensor, etc.), the adaptive cruise (Adaptive Cruise Control, ACC) or automatic parking system (Auto Parkig Assist, APA) of the intelligent driving assistance system (Advanced Driver Assistance System, ADAS) 1402, and the power system 1403 after the oil is lost. The braking request is sent. In other words, the brake pedal travel sensor 1401, the intelligent driving assistance system 1402, and the power system 1403 send the braking request to the braking demand calculation module 1301, and the braking demand calculation module 1301 can calculate the braking target according to the braking request, and then send the braking target to the braking force distribution module 1303. The value of the braking target can be a braking torque, a braking force, or a deceleration.

[0172] Step 2: Obtain vehicle load information. This can be obtained through the adhesion limit calculation module 1302. There are several ways to obtain this information:

[0173] Channel 1. Unloaded vehicle in the OEM design state: vehicle mass (G), static front axle load (Gf), static rear axle load (Gr), wheelbase L, center of mass height h, center of mass distance from front axle a, center of mass distance from rear axle b.

[0174] Channel 2: Obtaining the increase in axle load through the number of passengers: The number of passengers can be obtained through the passenger signal sensor 1407. For example, it can be obtained through the seat belt signal sensor of each seat (the number and distribution of passengers can also be directly obtained through the camera in the car), and the weight of each passenger is calculated as 75kg; thus, the updated vehicle weight / front and rear static axle load is obtained based on channel 1 (refer to the front and rear axle load data corresponding to different number of passengers of the main engine manufacturer, or simply load the front / rear passenger weight to the front / rear axle unloaded axle load respectively).

[0175] Channel 3: Obtain more accurate axle load values ​​through air spring stiffness information: Air spring stiffness information can be obtained through air spring controller 1404. For vehicles equipped with air springs, the air spring controller provides air pressure data of four-wheel air springs through the CAN network (the air pressure when the air spring adjusts the vehicle body posture after the passengers get on the vehicle), and then obtains the air spring stiffness of each wheel according to the known "air pressure-stiffness" curve of the air spring, and compares it with the design stiffness when unloaded (also obtained by checking the air spring air pressure value), and obtains the static wheel load of each wheel in the state of carrying people; the axle loads of the left and right wheels are averaged to obtain the static axle load of the single axle.

[0176] The above three channels have certain priorities, among which channel three is the most accurate, and channel two is the second most accurate. On this basis, it is also necessary to obtain the vehicle parking ramp information. The vehicle parking ramp information is obtained through the vehicle-mounted inertial sensor, which is the ramp information when all doors are closed and the vehicle has not started after power-on.

[0177] In particular, when the vehicle parking ramp information exceeds a certain slope value (for example, 8%), channel 1 is directly used for calculation without any correction. When the vehicle parking ramp information does not exceed a certain value, channel 3 is used for calculation first. If the actual conditions of channel 3 are not met, channel 2 is used for calculation.

[0178] The vehicle weight G, static front axle load Gf, static rear axle load Gr and vehicle wheelbase L obtained in the above manner are used to correct the distance a from the center of mass to the front axle and the distance b from the center of mass to the rear axle, wherein the correction formulas are shown in formulas (11) and (12).

[0179] Step 3: Calculate the front and rear dynamic axle loads. The calculation can be performed by the adhesion limit calculation module 1302. The calculation process is as follows:

[0180] Obtaining dynamic slope information: Calculate the deceleration Ax_brk generated by the braking torque based on the current total braking torque (front and rear energy recovery torque + front and rear friction braking torque, which can also be called front and rear axle electric braking force + front and rear friction braking force), that is, the front friction braking torque Fuf, the rear friction braking torque Fur, the front energy recovery torque EBf, the rear energy recovery torque EBr and the vehicle weight G. The calculation formula is shown in formula (3). Among them, the front friction braking torque can be obtained through the front friction brake 1409, the rear friction braking torque can be obtained through the front friction brake 1410, the front energy recovery torque can be obtained through the front energy recovery actuator 1411, and the rear energy recovery torque can be obtained through the rear energy recovery actuator 1412.

[0181] The actual deceleration Ax_IMU is then acquired by the inertial sensor 1408, and the slope information is calculated using formula (4). When the slope information is positive, it is downhill braking, and when the slope information is negative, it is uphill braking.

[0182] Finally, the front axle dynamic load and rear axle dynamic load corresponding to uphill braking, and the front axle dynamic load and rear axle dynamic load corresponding to downhill braking are calculated according to formulas (5)(6)(7)(8).

[0183] Step 4: Determine the road adhesion coefficient through road information.

[0184] First, road information can be obtained in the following ways:

[0185] It is obtained through the intelligent driving assistance system (ADAS) 1402. To be more precise, the road surface is directly obtained through the camera of the intelligent driving assistance system. The road surface information can be: dry asphalt / dry cement / wet asphalt / wet cement / ice surface / snow surface.

[0186] In the case where the ADAS system 1402 cannot provide direct road information, the wiper signal sensor 1405 is used to obtain whether it is raining. The wiper signal sensor 1405 can be a vehicle-mounted wiper switch sensor or a rain sensor. The road is set to dry asphalt by default, wet asphalt when it rains, and dry asphalt when it is not raining. In particular, the ambient temperature data can also be obtained through the vehicle-mounted ambient temperature sensor 1406. When the ambient temperature is lower than X°C (for example, 0°C), the road is directly set to a snow surface.

[0187] Secondly, the road adhesion coefficient is obtained by looking up the road surface table, and the road adhesion coefficient can be adjusted based on experience. The following Table 1 is for reference.

[0188] Table 1

[0189]

[0190] Finally, the front and rear axle adhesion limits are calculated by formulas (9) and (10). The adhesion limit calculation module 1302 sends the front and rear axle adhesion limits to the braking force distribution module 1303.

[0191] Step 5: Calculate the front and rear friction braking force distribution ratio. The front and rear axle regenerative braking force and friction braking force distribution are performed through the braking force distribution module. The regenerative braking force comes directly from the motor in the power system, and the friction braking force can come from the hydraulic brake (such as the electronic hydraulic brake system) or from the non-hydraulic brake such as the dry brake system. The calculation of the front and rear axle friction braking force distribution ratio is shown in formulas (1) and (2).

[0192] Step 6: Obtaining the front and rear motor recovery capacity limits. The front energy recovery actuator 1411 and the rear motor recovery actuator 1412 send the front motor recovery capacity limit and the rear motor recovery capacity limit to the braking demand calculation module 1301 , respectively. The braking demand calculation module 1301 sends the front and rear motor recovery capacity limit to the braking force distribution module 1303 .

[0193] Step 7: Based on the braking target, front and rear axle adhesion limit, front and rear motor recovery capacity limit, and front and rear friction braking force distribution ratio obtained in the previous step, and in combination with the vehicle drive type, the front and rear axle electric braking and front and rear axle friction braking are distributed based on the overall principle of distribution. The distribution is performed by the braking force distribution module 1303.

[0194] The general principle of distribution is: prioritize stability. On the basis of stability, give priority to implementing electric braking force (to improve the cruising range); the insufficient part of the electric braking force is supplemented by the frictional braking force. When supplementing the frictional braking force, on the premise of not breaking the stability boundary, try to implement it on both the front and rear axles.

[0195] The following combines Fig.15 to illustrate Step 7. Fig.15 It shows the specific distribution situation of a braking distribution method provided by an embodiment of the present application in an actual scenario. Among them, the braking target is T0, the limit value of the front motor recovery ability is FmLim, the limit value of the rear motor recovery ability is RmLim, the adhesion limit of the front axle is Φf, and the adhesion limit of the rear axle is Φr. Among them, the β curve is the distribution ratio of the front and rear frictional braking forces mentioned above, where β is the proportion of the front axle frictional braking force, and (1-β) is the proportion of the rear axle frictional braking force.

[0196] Step S1501: When T0 ≤ min(RmLim, Φr), all the braking forces are provided by the rear axle energy recovery (the rear motor performs electric braking), that is, a braking force of size T0 is distributed as the rear axle point braking force.

[0197] Step S1502: When Φr < T0 ≤ RmLim, a braking force of size RA = Φr is distributed to the rear axle electric braking force, and the remaining part FA1 = T0 - Φr is distributed according to the following rules:

[0198] When FA1 ≤ Φf, FA1 is all executed by the front axle. For rear-wheel drive RWD models, a braking force of size FA1 is distributed to the front axle frictional braking force; for all-wheel drive AWD models, the front axle gives priority to electric braking: when the front motor recovery ability limit FmLim ≥ FA1, the front axle is all electric braking; when the front motor recovery ability limit FmLim < FA1, the front axle executes electric braking of size FmLim and then executes frictional braking of size (FA1 - FmLim);

[0199] When FA1 > Φf, the front axle braking force is first distributed to Φf. (For RWD models, a front axle frictional braking force of size Φf is distributed. For AWD models, the front axle gives priority to distributing electric braking force: when the front motor recovery ability limit FmLim ≥ Φf, a front axle electric braking force of size Φf is distributed; when the front motor recovery ability limit FmLim < Φf, a front axle electric braking force of size FmLim is distributed and then a front axle frictional braking force of size (Φf - FmLim) is distributed.) The remaining part (T0 - Φr - Φf) is supplemented by the front and rear axle frictional braking forces, and the front and rear axle frictional braking is distributed according to the β curve.

[0200] Step S1503: When RmLim < T0 ≤ Φr, first distribute a rear axle electric braking force of size RA = RmLim.

[0201] For RWD vehicles: The remaining part (T0 - RmLim) is executed by friction braking, and the front and rear axle friction braking forces are distributed according to the β curve.

[0202] For AWD vehicles: The remaining part (T0 - RmLim) is preferentially distributed to the front axle point braking force. When the front motor capacity is sufficient, that is, when the front motor capacity limit FmLim ≥ (T0 - RmLim), a front axle electric braking with a magnitude of (T0 - RmLim) is directly distributed; when the front motor capacity is insufficient, that is, FmLim < T0 - RmLim, a front axle electric braking with a magnitude of FmLim is first distributed, and the remaining part (T0 - RmLim - FmLim) is supplemented by the front and rear axle friction braking, and the front and rear axle friction braking forces are distributed according to the β curve.

[0203] Step S1504: When RmLim ≤ Φr < T0, the rear axle first distributes an electric braking of RA = RmLim, that is, a rear axle electric braking force with a magnitude of RmLim is first distributed.

[0204] For RWD vehicles: The remaining part (T0 - RmLim) is entirely supplemented by the front and rear axle friction braking. The front and rear axle friction braking is first distributed according to the β curve; during the distribution process, it is judged whether the total rear axle braking force (electric braking force and friction braking) reaches Φr. If it reaches Φr, the rear axle remains unchanged and the front axle continues to increase. If the total front axle braking force also reaches Φf, then the remaining part (T0 - Φr - Φf) is supplemented by the front and rear axle friction braking, and the front and rear axle friction braking forces are distributed according to the β curve.

[0205] For AWD vehicles: The remaining part T1 = (T0 - RmLim), and the front axle stability and front motor capacity are first judged: when T1 < FmLim < Φf, a front axle electric braking force with a magnitude of FA = T1 is distributed; when FmLim ≤ Φf, a braking force with a magnitude of FmLim is distributed to the front axle electric braking, and the remaining part (T0 - RmLim - FmLim) is supplemented by the front and rear axle friction braking. The front and rear friction braking forces are distributed according to the β curve. After the total rear axle braking force reaches Φr, the rear axle friction braking remains unchanged and the front axle continues to increase; after the total front axle braking force also reaches Φf, then the remaining part (T0 - Φr - Φf) is supplemented by the front and rear axle friction braking, and the front and rear axle friction braking forces are distributed according to the β curve; when Φf < FmLim, a braking force with a magnitude of Φf is distributed to the front axle electric braking force, and the remaining part (T0 - RmLim - Φf) is first distributed to the rear axle friction braking force. When the total rear axle braking force reaches Φr, the remaining part (T0 - Φr - Φf) is supplemented by the front and rear axle friction braking, and the front and rear axle friction braking forces are distributed according to the β curve.

[0206] Step S1505: When Φr < RmLim < T0, a braking force with a magnitude of RA = Φr is distributed to the rear axle electric braking force.

[0207] For RWD vehicles: The remaining part (T0 - Φr) is first allocated to the front - axle frictional braking force until the front - axle frictional braking force reaches Φf. The remaining part (T0 - Φr - Φf) is supplemented by the front - and - rear - axle frictional braking, and the front - and - rear - axle frictional braking forces are distributed according to the β curve.

[0208] For AWD vehicles: The remaining part T1=(T0 - Φr). When T1 < FmLim < Φf, the braking force with a magnitude of FA = T1 is allocated to the front - axle electric braking; when FmLim ≤ Φf, first, the braking force with a magnitude of FmLim is allocated to the front - axle electric braking. For the remaining part (T0 - Φr - FmLim), the front - axle frictional braking is supplemented to Φf, and the remaining part (T0 - Φr - Φf) is supplemented by the front - and - rear - axle frictional braking, and the front - and - rear - axle frictional braking forces are distributed according to the β curve; when Φf < FmLim, first, the braking force with a magnitude of Φf is allocated to the front - axle electric braking, and the remaining part (T0 - Φr - Φf) is supplemented by the front - and - rear - frictional braking, where the front - and - rear - axle frictional braking forces are distributed according to the β curve.

[0209] Input the front - and - rear - axle frictional braking forces and the front - and - rear - axle electric braking forces calculated in steps S1501 to S1505 into the frictional braking execution system and the motor recovery execution system respectively, so that the vehicle performs braking with corresponding magnitudes. Specifically, send the front - axle frictional braking force to the front friction brake 1409, send the rear - axle frictional braking force to the rear friction brake 1410, send the front - axle electric braking force to the front energy recovery actuator 1411, and send the rear - axle electric braking force to the rear energy recovery actuator 1412.

[0210] Fig.16 It is a schematic structural diagram of a braking distribution device provided by an embodiment of the present application, as Fig.16 shown. The braking distribution device 1600 includes: an acquisition module 1601, a calculation module 1602, and a distribution module 1603, where:

[0211] The acquisition module 1601 is used to acquire the vehicle's on - vehicle load information;

[0212] The calculation module 1602 is used to determine the adhesion limits of the front and rear axles of the vehicle based on the on - vehicle load information and the environmental information of the vehicle;

[0213] The distribution module 1603 is used to, in response to receiving a vehicle braking request carrying a target braking force, based on the motor recovery capacity limit of the vehicle and the adhesion limits of the front and rear axles, use a braking distribution strategy to perform braking distribution of the target braking force between the electric braking force and the frictional braking force;

[0214] Among them, the allocation priority of the electric braking force in the braking allocation strategy is higher than the priority of the friction braking force, and the total braking force of the front and rear axles is not greater than the front and rear axle adhesion limit.

[0215] In some embodiments, the calculation module is further used to calculate the front and rear dynamic axle loads based on the vehicle load information and the braking force data of the vehicle; and determine the front and rear axle adhesion limits of the vehicle based on the front and rear dynamic axle loads and the environmental information.

[0216] In some embodiments, the vehicle load information includes: vehicle weight, vehicle wheelbase related information and vehicle front and rear roller radius; the calculation module is also used to determine the deceleration generated by the braking force based on the braking force data, the vehicle weight and the vehicle front and rear roller radius; based on the actual deceleration obtained and the deceleration generated by the braking force, determine the uphill and downhill type of the vehicle and the corresponding slope information; use the dynamic axle load calculation strategy corresponding to the uphill and downhill type, the slope information, the deceleration generated by the braking force, the vehicle weight and the vehicle wheelbase related information to determine the dynamic axle load.

[0217] In some embodiments, the calculation module is further used to determine the road surface type of the vehicle driving on based on the environmental information; and determine the front and rear axle adhesion limits of the vehicle based on the road surface type and the front and rear dynamic axle loads.

[0218] In some embodiments, the computing module is also used to obtain a road surface image captured by an image sensor, analyze the road surface image to obtain the road surface type; obtain other environmental signals not captured by the image sensor signal, and determine the road surface type based on the other environmental signals; the other environmental signals include at least one of the following: a vehicle-mounted wiper switch signal, a rain sensor signal, and temperature.

[0219] In some embodiments, the calculation module is also used to determine the target road adhesion coefficient corresponding to the road type by utilizing the mapping relationship between the preset road type and the road adhesion coefficient; and generate the front and rear axle adhesion limits based on the target road adhesion coefficient, the front and rear dynamic axle loads and the preset safety factor.

[0220] In some embodiments, the vehicle wheelbase related information includes: vehicle wheelbase, center of mass height and distance from center of mass to front and rear axles; the acquisition module is also used to obtain a preset vehicle wheelbase, center of mass height and front and rear roller radius of the vehicle; when the slope of the vehicle is greater than the maximum set slope, the initial vehicle weight of the vehicle is used as the vehicle weight, and the initial distance from the center of mass to the front and rear axles of the vehicle is used as the distance from the center of mass to the front and rear axles; when the slope of the vehicle is less than or equal to the maximum set slope, the vehicle weight is determined based on the initial vehicle weight and the number of passengers; the static front and rear axle loads are determined based on the initial axle load parameters and axle load increment parameters of the vehicle; the distance from the center of mass to the front and rear axles is determined based on the vehicle weight, the static front and rear axle loads and the vehicle wheelbase.

[0221] In some embodiments, the front and rear axle adhesion limits include a rear axle adhesion limit, the motor recovery capability limit includes a rear motor recovery capability limit, and the allocation module is further used to allocate a rear axle electric braking force having a target braking force when the target braking force is less than a minimum value between the rear motor recovery capability limit and the rear axle adhesion limit.

[0222] In some embodiments, the front and rear axle adhesion limits include a front axle adhesion limit and a rear axle adhesion limit, the motor recovery capacity limit includes a front motor recovery capacity limit and a rear motor recovery capacity limit, and the distribution module is further used to distribute the target braking force in the distribution order of rear axle electric braking force, front axle electric braking force and front axle friction braking force when the target braking force is greater than the rear axle adhesion limit and the target braking force is less than or equal to the rear motor recovery capacity limit; wherein the rear axle electric braking force is the rear axle adhesion limit, when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit and the front axle adhesion limit, and the sum of the front axle friction braking force and the front axle electric braking force is less than or equal to the front axle adhesion limit; when the vehicle is a rear-wheel drive vehicle, the front axle friction braking force is less than or equal to the front axle adhesion limit; when there is excess braking force after the sequential distribution, the excess braking force is supplemented to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0223] In some embodiments, the front and rear axle adhesion limits include a front axle adhesion limit and a rear axle adhesion limit, the motor recovery capacity limit includes a front motor recovery capacity limit and a rear motor recovery capacity limit, and the distribution module is further used to distribute the target braking force in the order of rear axle electric braking force, front axle electric braking force and friction braking force when the target braking force is greater than the rear motor recovery capacity limit and the target braking force is less than or equal to the rear axle adhesion limit; wherein the rear axle electric braking force is the rear motor recovery capacity limit, and when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit; the front axle friction braking force and the rear axle friction braking force in the friction braking force are obtained by distributing the remaining braking force based on a preset front and rear friction braking force distribution ratio.

[0224] In some embodiments, the front and rear axle adhesion limits include a front axle adhesion limit and a rear axle adhesion limit, the motor recovery capacity limit includes a front motor recovery capacity limit and a rear motor recovery capacity limit, and the allocation module is further used to allocate the target braking force in the order of rear axle electric braking force, front axle electric braking force and friction braking force when the target braking force is greater than the rear axle adhesion limit and the rear axle adhesion limit is greater than or equal to the rear motor recovery capacity limit; wherein the rear axle electric braking force is the rear motor recovery capacity limit, and when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front The motor recovery capacity limit and the front axle adhesion limit; the distribution process of the front axle friction braking force and the rear axle friction braking force in the friction braking force includes: distributing the remaining braking force based on a preset front and rear friction braking force distribution ratio until the front axle friction braking force reaches the front axle adhesion limit or the rear axle friction braking force reaches the rear axle adhesion limit, and adjusting the friction braking force of the target axle that has not reached the adhesion limit to the adhesion limit of the target axle; in the case of excess braking force after the sequential distribution, the excess braking force is supplemented and distributed to the front axle friction braking force and the rear axle friction braking force based on the preset front and rear friction braking force distribution ratio.

[0225] In some embodiments, the front and rear axle adhesion limits include a front axle adhesion limit and a rear axle adhesion limit, the motor recovery capacity limit includes a front motor recovery capacity limit and a rear motor recovery capacity limit, and the distribution module is further used to distribute the target braking force in the distribution order of rear axle electric braking force, front axle electric braking force and friction braking force when the target braking force is greater than the rear motor recovery capacity limit and the rear motor recovery capacity limit is greater than the rear axle adhesion limit; wherein the rear axle electric braking force is the rear axle adhesion limit, and when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit and the front axle adhesion limit; when there is excess braking force after the sequential distribution, the excess braking force is supplemented with the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

[0226] An embodiment of the present application provides a computer device, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the program, some or all of the steps in the above method are implemented.

[0227] The embodiment of the present application provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, some or all of the steps in the above method are implemented. The computer-readable storage medium can be transient or non-transient.

[0228] An embodiment of the present application provides a computer program, including a computer-readable code. When the computer-readable code is run in a computer device, a processor in the computer device executes some or all of the steps for implementing the above method.

[0229] The embodiment of the present application provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and when the computer program is read and executed by a computer, some or all of the steps in the above method are implemented. The computer program product can be implemented specifically by hardware, software or a combination thereof. In some embodiments, the computer program product is specifically embodied as a computer storage medium, and in other embodiments, the computer program product is specifically embodied as a software product, such as a software development kit (SDK) and the like.

[0230] It should be noted here that the description of the various embodiments above tends to emphasize the differences between the various embodiments, and the same or similar aspects can be referenced to each other. The description of the above device, storage medium, computer program and computer program product embodiments is similar to the description of the above method embodiment, and has similar beneficial effects as the method embodiment. For technical details not disclosed in the embodiments of the device, storage medium, computer program and computer program product of this application, please refer to the description of the method embodiment of this application for understanding.

[0231] Fig.16 A hardware entity diagram of a computer device provided in an embodiment of the present application is shown in FIG. Fig.16 As shown, the hardware entity of the computer device 1600 includes: a processor 1601 and a memory 1602, wherein the memory 1602 stores a computer program that can be run on the processor 1601, and the processor 1601 implements the steps in the method of any of the above embodiments when executing the program.

[0232] The memory 1602 stores computer programs that can be run on the processor. The memory 1602 is configured to store instructions and applications executable by the processor 1601. It can also cache data to be processed or processed by the processor 1601 and various modules in the computer device 1600 (for example, image data, audio data, voice communication data, and video communication data). This can be achieved through flash memory (FLASH) or random access memory (Random Access Memory, RAM).

[0233] An embodiment of the present application provides a computer storage medium, which stores one or more programs. The one or more programs can be executed by one or more processors to implement the steps of the braking allocation method in any of the above embodiments.

[0234] When the processor 1601 executes the program, the steps of any of the above-mentioned braking distribution sending methods are implemented. The processor 1601 generally controls the overall operation of the computer device 1600.

[0235] It should be noted here that the description of the above storage medium and device embodiments is similar to the description of the above method embodiments, and has similar beneficial effects as the method embodiments. For technical details not disclosed in the storage medium and device embodiments of this application, please refer to the description of the method embodiments of this application for understanding.

[0236] The processor may be at least one of an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Digital Signal Processing Device (DSPD), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a Central Processing Unit (CPU), a controller, a microcontroller, and a microprocessor. It is understandable that the electronic device that implements the functions of the processor may also be other, and the embodiments of the present application are not specifically limited.

[0237] The above-mentioned computer storage medium / memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a magnetic random access memory (FRAM), a flash memory (Flash Memory), a magnetic surface memory, an optical disk, or a compact disc read-only memory (CD-ROM) and the like; it can also be various terminals including one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc.

[0238] The above is only an implementation method of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A braking distribution method, characterized in that: The method comprises: Obtain vehicle load information; Determining the front and rear axle adhesion limits of the vehicle based on the vehicle load information and the environment information of the vehicle; In response to a vehicle braking request carrying a target braking force, based on a motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits, the target braking force is brake-distributed between an electric braking force and a friction braking force using a braking distribution strategy; Wherein, the allocation priority of the electric braking force in the braking allocation strategy is higher than the priority of the friction braking force, and the total braking force of the front and rear axles is not greater than the front and rear axle adhesion limit; The front and rear axle adhesion limits include a front axle adhesion limit and a rear axle adhesion limit, the motor recovery capability limit includes a front motor recovery capability limit and a rear motor recovery capability limit, and the target braking force is braked between the electric braking force and the friction braking force using a braking distribution strategy based on the motor recovery capability limit of the vehicle and the front and rear axle adhesion limits, including: When the target braking force is greater than the rear axle adhesion limit and the target braking force is less than or equal to the rear motor recovery capacity limit, the target braking force is distributed in the order of rear axle electric braking force, front axle electric braking force and front axle friction braking force; Wherein, the rear axle electric braking force is the rear axle adhesion limit, when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit and the front axle adhesion limit, and the sum of the front axle friction braking force and the front axle electric braking force is less than or equal to the front axle adhesion limit; when the vehicle is a rear-wheel drive vehicle, the front axle friction braking force is less than or equal to the front axle adhesion limit; When there is excess braking force after the sequential distribution, the excess braking force is supplementarily distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

2. The method according to claim 1, characterized in that The determining the front and rear axle adhesion limits of the vehicle based on the vehicle load information and the environment information of the vehicle includes: Calculating front and rear dynamic axle loads based on the vehicle load information and the braking force data of the vehicle; Based on the front and rear dynamic axle loads and the environmental information, front and rear axle adhesion limits of the vehicle are determined.

3. The method according to claim 2, characterized in that The vehicle load information includes: vehicle weight, vehicle wheelbase related information, and the front and rear dynamic axle loads are calculated based on the vehicle load information and the vehicle braking force data, including: Determine the deceleration generated by the braking force based on one or more of the braking force data, the vehicle weight, and the front and rear roller radii of the vehicle; Determining the uphill and downhill types of the vehicle and corresponding slope information based on the acquired actual deceleration and the deceleration generated by the braking force; The dynamic axle load is determined by using the dynamic axle load calculation strategy corresponding to the uphill and downhill types, the slope information, the deceleration generated by the braking force, the vehicle weight and the vehicle wheelbase related information.

4. The method according to claim 2, characterized in that: The determining the front and rear axle adhesion limits of the vehicle based on the front and rear dynamic axle loads and the environmental information includes: Based on the environmental information, determining the road type of the road on which the vehicle is traveling; Based on the road surface type and the front and rear dynamic axle loads, front and rear axle adhesion limits of the vehicle are determined.

5. The method according to any one of claims 1 to 4, characterized in that: The obtaining of vehicle load information includes: Get the preset vehicle wheelbase and center of mass height; When the vehicle's parking slope is greater than the maximum set slope, the vehicle's initial vehicle weight is used as the vehicle weight, and the distance between the vehicle's initial center of mass and the front and rear axles is used as the distance between the center of mass and the front and rear axles; When the vehicle parking slope is less than or equal to the maximum set slope, the vehicle weight is determined based on the initial vehicle weight and the number of passengers; Determine the static front and rear axle loads based on the vehicle's initial axle load parameters and axle load increment parameters; Determining the distance between the center of mass and the front and rear axles based on the vehicle weight, the static front and rear axle loads and the vehicle wheelbase; The vehicle wheelbase, the center of mass height, the vehicle weight and the distance between the center of mass and the front and rear axles are used as vehicle load information.

6. The method according to any one of claims 1 to 4, characterized in that: The method of distributing the target braking force between the electric braking force and the friction braking force by using a braking distribution strategy based on the motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits includes: When the target braking force is greater than the rear motor recovery capacity limit and the target braking force is less than or equal to the rear axle adhesion limit, the target braking force is distributed in the order of rear axle electric braking force, front axle electric braking force and friction braking force; Among them, the rear axle electric braking force is the recovery capacity limit of the rear motor. When the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the recovery capacity limit of the front motor. The front axle friction braking force and the rear axle friction braking force in the friction braking force are obtained by distributing the remaining braking force based on a preset front and rear friction braking force distribution ratio.

7. The method according to any one of claims 1 to 4, characterized in that: The method of distributing the target braking force between the electric braking force and the friction braking force by using a braking distribution strategy based on the motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits includes: When the target braking force is greater than the rear axle adhesion limit, and the rear axle adhesion limit is greater than or equal to the rear motor recovery capacity limit, the target braking force is distributed in the order of rear axle electric braking force, front axle electric braking force and friction braking force; Wherein, the rear axle electric braking force is the rear motor recovery capacity limit, and when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit and the front axle adhesion limit; the distribution process of the front axle friction braking force and the rear axle friction braking force in the friction braking force includes: distributing the remaining braking force based on a preset front and rear friction braking force distribution ratio until the front axle friction braking force reaches the front axle adhesion limit or the rear axle friction braking force reaches the rear axle adhesion limit, and adjusting the friction braking force of the target axle that has not reached the adhesion limit to the adhesion limit of the target axle; When there is excess braking force after the sequential distribution, the excess braking force is supplementarily distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

8. The method according to any one of claims 1 to 4, characterized in that: The method of distributing the target braking force between the electric braking force and the friction braking force by using a braking distribution strategy based on the motor recovery capacity limit of the vehicle and the front and rear axle adhesion limits includes: When the target braking force is greater than the rear motor recovery capability limit, and the rear motor recovery capability limit is greater than the rear axle adhesion limit, the target braking force is distributed in the order of rear axle electric braking force, front axle electric braking force and friction braking force; The rear axle electric braking force is the rear axle adhesion limit, and when the vehicle is a four-wheel drive vehicle, the front axle electric braking force is less than or equal to the front motor recovery capacity limit and the front axle adhesion limit; When there is excess braking force after the sequential distribution, the excess braking force is supplementarily distributed to the front axle friction braking force and the rear axle friction braking force based on a preset front and rear friction braking force distribution ratio.

9. A vehicle comprising a memory and a processor, wherein the memory stores a computer program executable on the processor, characterized in that: When the processor executes the program, the steps in the method according to any one of claims 1 to 8 are implemented.

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