Vehicle braking control method and device and vehicle

Abstract

The embodiment of the invention relates to the technical field of vehicles, and discloses a vehicle braking control method and device and a vehicle. The vehicle braking control method comprises the steps that under the condition that the vehicle is in a sliding state, an electric braking correction coefficient is determined based on road surface information and speed information of the vehicle; the road surface information is used for representing parameter values of road surface parameters influencing the braking performance; based on the electric braking correction coefficient and the maximum allowable electric braking torque of the sliding working condition of the braking motor, the target electric braking torque of the vehicle is determined; determining a hydraulic compensation torque based on a total braking torque of the vehicle and the target electric braking torque; and brake control is conducted on the vehicle based on the target electric brake torque and the hydraulic compensation torque. By means of the technical scheme, the target electric braking torque can be accurately matched with the road surface information and the speed information of the vehicle, and therefore the braking control accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a vehicle braking control method and device and vehicle. BACKGROUND

[0002] At present, in order to improve the endurance capability, new energy vehicles generally adopt the technical scheme that the driving motor is used for energy recovery in the vehicle sliding stage. The inertial kinetic energy of the vehicle is converted into electric energy and stored in the power battery, so as to realize effective reduction of energy consumption, which has become one of the core means of energy-saving design of new energy vehicles. However, during the vehicle driving process, the operation of the brake pedal and the accelerator pedal is directly related to the driving safety. In the actual sliding and pedal braking coordination scene, the cooperative optimization of energy recovery and braking safety still faces significant challenges. Therefore, how to improve the braking safety of the vehicle under the premise of ensuring the energy recovery efficiency, and how to balance the dual demands of energy saving and safety have become key problems to be solved in the field of sliding energy recovery technology of new energy vehicles. SUMMARY

[0003] In view of the above deficiencies of the prior art, the purpose of the present application is to provide a vehicle braking control method, device and vehicle, which aims to improve the braking safety of the vehicle.

[0004] In a first aspect, the embodiments of the present application provide a vehicle braking control method, comprising: determining an electric braking correction coefficient based on road surface information and speed information of the vehicle in a case that the vehicle is in a sliding state; the road surface information is used to represent the parameter value of the road surface parameter affecting the braking performance; determining a target electric braking torque of the vehicle based on the electric braking correction coefficient and the maximum allowed electric braking torque of the driving motor in the sliding working condition; determining a hydraulic compensation torque based on the total braking torque of the vehicle and the target electric braking torque; and performing braking control on the vehicle based on the target electric braking torque and the hydraulic compensation torque.

[0005] According to the above technical means, the electric braking correction coefficient is actively adjusted through the dynamic feedback of the road surface information and the speed information, the target electric braking torque and the energy recovery intensity are limited in a targeted manner, the risks such as wheel slip and vehicle out of control caused by excessive electric braking output in scenes such as low adhesion road and curve are avoided from the source, and the safety and stability of sliding braking are significantly improved. At the same time, with the help of the accurate compensation of the hydraulic compensation torque, in the case that the electric braking torque is constrained, the total braking torque is ensured to always match the sliding deceleration requirement, which does not affect the braking effect and sliding smoothness, and can maximize the energy recovery benefit within the safety boundary.

[0006] In a possible embodiment, the road surface information comprises a road surface slope and a road surface adhesion coefficient; the speed information comprises a lateral acceleration; and determining the electric braking correction coefficient based on the road surface information and the speed information of the vehicle comprises: determining a first electric braking correction coefficient based on the road surface slope; determining a second electric braking correction coefficient based on the road surface adhesion coefficient; determining a third electric braking correction coefficient based on the lateral acceleration; and determining the electric braking correction coefficient based on the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking correction coefficient.

[0007] According to the technical means, the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking correction coefficient are determined based on the road surface slope, the road surface adhesion coefficient, and the lateral acceleration, and the electric braking correction coefficient is determined in combination, so that the electric braking correction coefficient can respond to braking constraints in different scenarios such as slope, road adhesion, and lateral posture, and ensure that the electric braking torque does not break through any safety boundary at all times, thereby avoiding risks caused by omission of single working condition consideration from the root, and reserving energy recovery space within a safe range.

[0008] In an embodiment, the speed information further comprises a vehicle speed; and determining the first electric braking correction coefficient based on the road surface slope comprises: in a case where the vehicle is on a downhill slope, determining the first electric braking correction coefficient based on the road surface slope, the vehicle speed, and a first mapping relationship; and the first mapping relationship is used to represent a corresponding relationship between downhill slope of the vehicle, downhill speed of the vehicle, and the electric braking correction coefficient.

[0009] According to the technical means, in a case where the vehicle is on a downhill slope, the maximum allowed electric braking torque in the coasting working condition is corrected based on the road surface slope, the vehicle speed, and the first mapping relationship, so that the target electric braking torque can accurately adapt to the core demand of the downhill scenario, avoiding vehicle sliding due to gravity acceleration, preventing the motor from being overloaded and overheated, and balancing energy recovery efficiency and braking safety.

[0010] In some embodiments, determining the second electric braking correction coefficient based on the road surface adhesion coefficient comprises: in a case where the road surface adhesion coefficient is less than or equal to a preset road surface adhesion coefficient, determining the second electric braking correction coefficient based on the road surface adhesion coefficient and a second mapping relationship; and the second mapping relationship is used to represent a corresponding relationship between the road surface adhesion coefficient of the vehicle and the electric braking correction coefficient.

[0011] According to the above technical means, in the case that the road surface adhesion coefficient of the vehicle is less than or equal to the preset road surface adhesion coefficient, the maximum allowable electric braking torque in the coasting working condition is corrected through the road surface adhesion coefficient and the second mapping relationship, so that the target electric braking torque can accurately adapt to the safety constraint of the low adhesion scene, avoiding wheel slip and locking caused by excessive electric braking torque exceeding the road surface adhesion limit, and maximizing the energy recovery effect of electric braking under the premise of ensuring effective wheel adhesion, achieving a balance between braking stability and recovery efficiency in the low adhesion road surface coasting.

[0012] In an example embodiment, the third electric braking correction coefficient is determined based on the lateral acceleration, including: in the case that the lateral acceleration is greater than or equal to a preset acceleration threshold, determining the third electric braking correction coefficient based on the lateral acceleration and a third mapping relationship; the third mapping relationship is used to represent the corresponding relationship between the lateral acceleration of the vehicle and the electric braking correction coefficient.

[0013] According to the above technical means, in the case that the lateral acceleration is greater than or equal to the preset acceleration threshold, the maximum allowable electric braking torque in the coasting working condition is corrected through the lateral acceleration and the third mapping relationship, so that the target electric braking torque can accurately adapt to the lateral force state of the vehicle, avoiding excessive electric braking torque interfering with the steering characteristics, causing sideslip or spinout, and ensuring the lateral stability of the vehicle, and retaining a reasonable energy recovery space under the premise of not affecting the driving posture, achieving a balance between braking safety and recovery efficiency in the steering scene.

[0014] In an example embodiment, the speed information further includes: a vehicle speed; determining the electric braking correction coefficient based on the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking correction coefficient, including: determining a coasting deceleration demand based on the vehicle speed; in the case that the ratio between the coasting deceleration demand and the target deceleration is greater than or equal to a preset ratio, determining a fourth electric braking correction coefficient based on the ratio and a fourth mapping relationship; determining the minimum value of the first electric braking correction coefficient, the second electric braking correction coefficient, the third electric braking correction coefficient, and the fourth electric braking correction coefficient as the electric braking correction coefficient; wherein the target deceleration is the deceleration corresponding to the maximum allowable electric braking torque in the coasting working condition; the fourth mapping relationship is used to represent the corresponding relationship between the ratio between the coasting deceleration demand and the target deceleration and the electric braking correction coefficient; and the preset ratio is greater than 1.

[0015] According to the above technical means, the coasting deceleration requirement is accurately matched through the vehicle speed, and then the matching difference between the coasting deceleration requirement and the maximum capability of the electric brake is dynamically responded through the fourth mapping relationship; finally, the minimum value among the first electric brake correction coefficient, the second electric brake correction coefficient, the third electric brake correction coefficient and the fourth electric brake correction coefficient is taken as the electric brake correction coefficient, which not only covers the working condition constraints of slope, adhesion coefficient and lateral acceleration, but also takes into account the torque adaptation of the coasting deceleration requirement, so as to ensure that the electric brake torque is always within the safety boundary, avoid risks such as wheel slip and vehicle out of control, maximize the energy recovery efficiency while meeting the deceleration requirement, and achieve the balance between brake safety and performance in multi-dimensional working conditions.

[0016] In the example embodiment, the first electric brake correction coefficient is 1 when the vehicle is on an uphill; the second electric brake correction coefficient is 1 when the road adhesion coefficient is greater than the preset road adhesion coefficient; the third electric brake correction coefficient is 1 when the lateral acceleration is less than the preset acceleration threshold; and the fourth electric brake correction coefficient is 1 when the ratio between the coasting deceleration requirement and the target deceleration is less than the preset ratio.

[0017] According to the above technical means, when the vehicle is on an uphill (no slope constraint), on a high adhesion road surface (no risk of slipping), has a low lateral acceleration (no risk of side slipping) or the deceleration requirement does not exceed the electric brake capability (no need for hydraulic emergency compensation), the correction coefficient remains unchanged at 1, which allows the electric brake torque to be close to the maximum allowed electric brake torque in the coasting working condition, thereby maximizing the energy recovery benefit.

[0018] In the example embodiment, the determination process of the maximum allowed electric brake torque in the coasting working condition includes: determining the maximum allowed electric brake torque in the coasting working condition based on the maximum recovery torque, the speed, the power generation efficiency of the brake motor and the maximum allowed charging power of the power battery.

[0019] According to the above technical means, the maximum allowed electric brake torque in the coasting working condition that meets the brake motor limit and the power battery limit can be determined based on the maximum recovery torque, the speed, the power generation efficiency of the brake motor and the maximum allowed charging power of the power battery, thereby ensuring the safe use of the brake motor and the power battery.

[0020] In the example embodiment, the determination of the maximum allowed electric brake torque in the coasting working condition based on the maximum recovery torque, the speed, the power generation efficiency of the brake motor and the maximum allowed charging power of the power battery includes: determining the electric brake torque that can be supported by the power battery based on the speed, the power generation efficiency and the maximum allowed charging power; and determining the smaller value between the maximum recovery torque and the electric brake torque that can be supported by the power battery as the maximum allowed electric brake torque in the coasting working condition.

[0021] According to the above technical means, the electric braking torque that can be supported by the battery side is accurately derived based on the rotation speed, the power generation efficiency and the maximum allowable charging power of the power battery, so as to avoid overcharging and heating of the battery caused by over-limit charging power, the maximum recovered torque of the motor is taken as the upper limit of the mechanical constraint, and finally the minimum value of the two is taken as the maximum allowable electric braking torque in the coasting condition, so as to completely avoid the risk of component overload damage from the two dimensions of motor mechanical safety and battery charging safety.

[0022] In the example embodiment, the speed information includes a vehicle speed, and the determination process of the total braking torque includes determining a coasting deceleration demand based on the vehicle speed, determining a total braking force of the vehicle based on the coasting deceleration demand, and determining the total braking torque based on the total braking force and a conversion coefficient between the braking force and the braking torque.

[0023] According to the above technical means, the coasting deceleration demand is derived based on the vehicle speed, the total braking force is determined through the coasting deceleration demand, and the total braking torque is determined in combination with the conversion coefficient between the braking force and the braking torque, so as to convert the abstract deceleration demand into a quantitative torque instruction that can be directly responded by the braking system, and to provide a precise reference for subsequent allocation of the electric braking and the hydraulic compensation torque through the standardized calculation logic.

[0024] In a second aspect, the application provides a vehicle braking control device, including a determination module and a control module. The determination module is configured to determine an electric braking correction coefficient based on road surface information and speed information of the vehicle when the vehicle is in a coasting state, the road surface information is used to represent a parameter value of a road surface parameter affecting braking performance, and determine a target electric braking torque of the vehicle based on the electric braking correction coefficient and a maximum allowable electric braking torque of the braking motor in a coasting condition, and determine a hydraulic compensation torque based on a total braking torque of the vehicle and the target electric braking torque.

[0025] In a third aspect, the application provides a vehicle, including a vehicle body, a collection device, a braking motor, a hydraulic execution unit, and the vehicle braking control device of the second aspect.

[0026] In a fourth aspect, the application provides an electronic device, including a processor and a memory, and the memory stores instructions executable by the processor. The processor is configured to execute the instructions, so that the electronic device implements the vehicle braking control method of the first aspect.

[0027] In a fifth aspect, the application provides a computer readable storage medium, and the computer readable storage medium stores computer program instructions, and the computer program instructions are executed by the processor to implement the vehicle braking control method of the first aspect.

[0028] In a sixth aspect, the present application provides a computer program product, which comprises computer program instructions, and the computer program instructions realize the vehicle braking control method of the first aspect when executed by a processor.

[0029] It should be noted that the technical effects brought by any one of the implementation manners of the second aspect to the sixth aspect can refer to the technical effects brought by the corresponding implementation manners in the first aspect, which will not be repeated here.

[0030] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background art, the drawings needed to be used by the embodiments of the present application will be described below.

[0032] Figure 1 A schematic diagram of a vehicle braking architecture disclosed by the embodiments of the present application; Figure 2 A schematic diagram of a functional architecture of a vehicle braking control device disclosed by the embodiments of the present application; Figure 3 A schematic diagram of a vehicle braking control method disclosed by the embodiments of the present application; Figure 4 A schematic diagram of another vehicle braking control method disclosed by the embodiments of the present application; Figure 5 A schematic diagram of another vehicle braking control method disclosed by the embodiments of the present application; Figure 6 A schematic diagram of another vehicle braking control method disclosed by the embodiments of the present application; Figure 7 A schematic diagram of another vehicle braking control method disclosed by the embodiments of the present application; Figure 8 A schematic diagram of another vehicle braking control method disclosed by the embodiments of the present application; Figure 9 A schematic diagram of a structure of an electronic device disclosed by the embodiments of the present application. DETAILED DESCRIPTION

[0033] The terms "first", "second", etc. are only used for descriptive purposes and do not have any sequential or technical meaning, nor can they be understood to indicate or imply relative importance or to imply a number of the technical features indicated. The directional terms mentioned in the present application, such as "up", "down", "front", "back", "left", "right", "inner", "outer", etc., are only the orientation shown in the drawings. The directional terms used are for better, clearer illustration and understanding of the present application, and do not indicate the orientation of the device or component in the actual application scenario.

[0034] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection" should be understood broadly, for example, "connection" can be detachable connection, or non-detachable connection; can be direct connection, or indirect connection through intermediate medium.

[0035] The embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0036] Please refer to Figure 1 , Figure 1 The schematic diagram of the braking architecture of the vehicle disclosed in the embodiments of the present application is shown. The vehicle can be, but is not limited to, a pure electric vehicle (PEV / BEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), a new energy vehicle, etc.

[0037] In the embodiments of the present application, the vehicle 100 includes a vehicle body 101, a collection device 102, a braking motor 103, a hydraulic execution unit 104, and a vehicle braking control device 105. The collection device 102 is mounted at a preset monitoring position of the vehicle body 101 (such as a vehicle head sensor mounting area, a vehicle body 101 side detection point, and a chassis data collection position, etc.), the braking motor 103 is disposed in a power transmission related area of the vehicle body 101 (such as near the drive axle or corresponding position of the wheel brake assembly), the hydraulic execution unit 104 is installed in a hydraulic brake system integrated area of the vehicle body 101 (such as beside the brake master cylinder or chassis hydraulic control module installation position), and the vehicle braking control device 105 is placed in a control module concentrated installation area of the vehicle body 101 (such as inside the electronic control box below the driver's cabin, the central control cabin of the chassis, or the front electrical integration area of the vehicle body 101, etc.), which is the core control center of the entire braking system, facilitating the overall connection of each execution component and efficient transmission of control instructions.

[0038] The acquisition device 102, the brake motor 103, and the hydraulic execution unit 104 are in bidirectional communication connection with the vehicle brake control device 105, forming a closed-loop control link: the acquisition device 102 collects the road surface information and speed information of the vehicle in real time, and synchronously transmits the collected high-precision data to the vehicle brake control device 105; after receiving the data, the vehicle brake control device 105 comprehensively judges the working condition through the built-in algorithm, accurately calculates the total brake torque required by the vehicle at present, then dynamically disassembles the total brake torque into a hydraulic compensation torque and an electric brake torque based on a preset distribution strategy, and sends control instructions to the hydraulic execution unit 104 and the brake motor 103 respectively, drives the hydraulic execution unit 104 to output a mechanical brake force through the hydraulic compensation torque, controls the brake motor 103 to realize energy recovery and electric brake force output through the electric brake torque, and the two complete the vehicle brake process cooperatively.

[0039] As a feasible implementation manner, the acquisition device 102 can include a rainfall sensor, an acceleration sensor, a wheel speed sensor, a brake pedal sensor, and an accelerator pedal sensor. Among them, the rainfall sensor can be used to determine whether it is raining; the acceleration sensor can be used to detect the slope and the longitudinal deceleration; and the wheel speed sensor can be used to obtain the lateral acceleration and the vehicle speed.

[0040] As a feasible implementation manner, the vehicle brake control device 105 can adopt integrated design, specifically integrating a central controller, a brake single-machine controller, and a hydraulic control unit: the central controller serves as a core decision module, is responsible for overall planning of analysis and processing of environmental and operating data, calculation of total brake torque, and formulation of torque distribution strategy; the brake motor controller focuses on electric brake related control logic, and ensures that the torque output of the brake motor 103 accurately responds to the instruction; and the hydraulic control unit is specifically responsible for execution control of the hydraulic compensation torque, and guarantees the action stability and timeliness of the hydraulic execution unit 104, and the three cooperatively realize efficient and accurate control of the brake system.

[0041] In the example embodiment, the central controller can be a vehicle control unit (VCU) or a special brake energy recovery controller.

[0042] In the example embodiment, the brake motor controller can be an independent motor control unit (MCU), or a special control module integrated in the drive motor controller, and its core function is to realize closed-loop control of the torque based on the electric brake torque instruction issued by the central controller, combined with the real-time speed, temperature, and other state parameters of the brake motor 103, through vector control algorithm, to ensure the rapidity and accuracy of the electric brake response.

[0043] In an example embodiment, the hydraulic control unit can be a mature and high-performance hydraulic control module such as an Electronic Stability Program (ESP), an ibooster, etc. After receiving the hydraulic compensation torque instruction issued by the central controller, the hydraulic control unit quickly converts the instruction into a corresponding wheel cylinder pressure control signal, accurately and efficiently drives the hydraulic execution unit 104 to adjust the wheel cylinder pressure, and thus generates a compensation braking force that meets the requirements.

[0044] Please refer to Figure 2 , Figure 2 A schematic diagram of the functional architecture of the vehicle brake control device disclosed in the embodiments of the present application is shown. The vehicle brake control device 105 includes a determination module 201 and a control module 202.

[0045] The determination module 201 is configured to determine an electric brake correction coefficient based on road surface information and speed information of the vehicle when the vehicle is in a coasting state; the road surface information is used to represent a parameter value of a road surface parameter that affects the braking performance; determine a target electric brake torque of the vehicle based on the electric brake correction coefficient and the maximum allowable electric brake torque of the braking motor in the coasting condition; and determine a hydraulic compensation torque based on the total brake torque of the vehicle and the target electric brake torque.

[0046] The control module 202 is configured to perform brake control on the vehicle based on the target electric brake torque and the hydraulic compensation torque.

[0047] In an example embodiment, the road surface information includes road surface slope and road surface adhesion coefficient; the speed information includes lateral acceleration; the determination module 201 is specifically configured to determine a first electric brake correction coefficient based on the road surface slope; determine a second electric brake correction coefficient based on the road surface adhesion coefficient; determine a third electric brake correction coefficient based on the lateral acceleration; and determine the electric brake correction coefficient based on the first electric brake correction coefficient, the second electric brake correction coefficient, and the third electric brake correction coefficient.

[0048] In an example embodiment, the speed information further includes vehicle speed; the determination module 201 is specifically configured to determine a first electric brake correction coefficient based on the road surface slope, the vehicle speed, and a first mapping relationship when the vehicle is on a downhill; and the first mapping relationship is used to represent a corresponding relationship between the downhill slope of the vehicle, the downhill speed, and the electric brake correction coefficient.

[0049] In an example embodiment, the determination module 201 is specifically configured to determine a second electric brake correction coefficient based on the road surface adhesion coefficient and a second mapping relationship when the road surface adhesion coefficient is less than or equal to a preset road surface adhesion coefficient; and the second mapping relationship is used to represent a corresponding relationship between the road surface adhesion coefficient of the vehicle and the electric brake correction coefficient.

[0050] In an example embodiment, the determining module 201 is specifically configured to determine a third electric brake correction coefficient based on the lateral acceleration and a third mapping relationship in a case where the lateral acceleration is greater than or equal to a preset acceleration threshold.

[0051] In an example embodiment, the speed information further includes a vehicle speed, and the determining module 201 is specifically configured to determine a coasting deceleration demand based on the vehicle speed, determine a fourth electric brake correction coefficient based on a ratio between the coasting deceleration demand and a target deceleration and a fourth mapping relationship in a case where the ratio is greater than or equal to a preset ratio, and determine the electric brake correction coefficient as a minimum value among the first electric brake correction coefficient, the second electric brake correction coefficient, the third electric brake correction coefficient and the fourth electric brake correction coefficient; the target deceleration is a deceleration corresponding to a maximum allowed electric brake torque in the coasting condition; the fourth mapping relationship is used to represent a corresponding relationship between the ratio between the coasting deceleration demand and the target deceleration and the electric brake correction coefficient; and the preset ratio is greater than 1.

[0052] In an example embodiment, the second electric brake correction coefficient is 1 in a case where the road adhesion coefficient is greater than a preset road adhesion coefficient, the third electric brake correction coefficient is 1 in a case where the lateral acceleration is less than a preset acceleration threshold, and the fourth electric brake correction coefficient is 1 in a case where the ratio between the coasting deceleration demand and the target deceleration is less than a preset ratio.

[0053] In an example embodiment, the determination process of the maximum allowed electric brake torque in the coasting condition includes determining the maximum allowed electric brake torque in the coasting condition based on a maximum recovery torque, a speed, a power generation efficiency of the brake motor and a maximum allowed charging power of the power battery.

[0054] In an example embodiment, the maximum allowed electric brake torque in the coasting condition is determined based on the speed, the power generation efficiency and the maximum allowed charging power of the power battery.

[0055] Please refer to Figure 3 , Figure 3 A flowchart of a vehicle brake control method disclosed in an example embodiment of the present application is shown in FIG. 1. The vehicle brake control method specifically includes the following steps: S301, in a case where a vehicle is in a coasting state, determining an electric brake correction coefficient based on road information and speed information of the vehicle.

[0056] The road information is used to represent a parameter value of a road parameter affecting brake performance. The road information includes a road slope and a road adhesion coefficient.

[0057] The speed information is used to represent the motion state of the vehicle during the coasting process, and includes lateral acceleration and vehicle speed.

[0058] The coasting state is used to represent a driving state in which the accelerator pedal and the brake pedal are not triggered, the vehicle only relies on inertia, and the driving motor does not output driving torque. In this state, the vehicle has core requirements for energy recovery and coasting braking.

[0059] The electric braking correction coefficient is a parameter value used to correct the maximum allowable electric braking torque in the coasting working condition.

[0060] In the example embodiment, when the vehicle is driving on a large slope section (especially in a downhill scenario), it is difficult to rely only on electric braking to provide sustained and sufficient braking force, which may cause the vehicle to accelerate and cause safety hazards. At the same time, during the long downhill process, the brake motor is prone to overheating due to continuous operation and enters the protection mode, resulting in a sharp decline in energy recovery capability. Therefore, the electric braking correction coefficient (less than 1) is reduced to lower the maximum allowable electric braking torque in the coasting working condition to avoid the above problems.

[0061] On low adhesion road surfaces (such as rainy, icy, and snowy road surfaces), if the electric braking torque is too large, it is easy to cause the wheels to lock or slip, thereby triggering the ABS system to intervene, which affects the driving safety and reduces the energy recovery efficiency. Therefore, the electric braking correction coefficient is set to be less than 1 to reduce the maximum allowable electric braking torque to adapt to the braking requirements of low adhesion road surfaces.

[0062] If the lateral acceleration is large during the coasting process (such as when the vehicle is turning), an excessive electric braking torque may interfere with the lateral stability of the vehicle and affect the handling safety. Therefore, the electric braking correction coefficient needs to be dynamically adjusted according to the size of the lateral acceleration to reasonably lower the maximum allowable electric braking torque and ensure the lateral handling performance of the vehicle.

[0063] When the vehicle is coasting at a high speed and the driver has a rapid coasting deceleration requirement, it is often difficult to meet the expected deceleration by relying only on electric braking. At this time, the maximum allowable electric braking torque in the coasting working condition needs to be slightly reduced (the electric braking correction coefficient is less than 1) to reserve space for the intervention of hydraulic braking and ensure the braking effect and safety.

[0064] As a feasible implementation manner, for the four core influencing parameters of road slope, road adhesion coefficient, lateral acceleration and vehicle speed, multi-level division thresholds are set (for example, the road adhesion coefficient is divided into three levels of high, medium and low); based on a large amount of real vehicle road test data and simulation test results, a mapping relationship table of different levels of each parameter (road information and speed information) and the corresponding electric brake correction coefficient is established, to ensure that each parameter level matches the electric brake correction coefficient adapted to the safety requirements of the working condition; when the vehicle is in a sliding state, the acquisition device collects the actual values of the road information and the speed information in real time, matches the corresponding level of each parameter by comparing with the preset threshold, and then determines the electric brake correction coefficient corresponding to each parameter according to the mapping relationship table, and selects the minimum value from the multiple electric brake correction coefficients as the final electric brake correction coefficient. This design can ensure that various key braking influencing factors such as road adhesion, slope adaptation, lateral stability and vehicle speed matching are within the safety boundary, thereby realizing accurate and dynamic correction of the maximum allowed electric brake torque under the sliding working condition, and taking into account the braking safety and energy recovery efficiency.

[0065] S302, based on the electric brake correction coefficient and the maximum allowed electric brake torque of the braking motor under the sliding working condition, determining the target electric brake torque of the vehicle.

[0066] In some embodiments, the maximum allowed electric brake torque under the sliding working condition is used to represent the maximum electric brake torque threshold that the braking motor can stably output without causing safety hazards or damaging core components, under the vehicle sliding state, by comprehensively considering the mechanical performance limit of the braking motor, the charging constraint of the power battery and the braking safety requirement of the whole vehicle.

[0067] As a feasible implementation manner, the determination process of the maximum allowed electric brake torque under the sliding working condition includes: based on the rated parameters (such as rated torque and rated speed) of the braking motor, the heat dissipation ability threshold of the thermal management system and the safety redundancy design of the whole vehicle braking system, presetting a basic maximum allowed electric brake torque through static calibration; then combining the real-time battery temperature and motor temperature of the vehicle, slightly correcting the basic threshold, and finally obtaining the maximum allowed electric brake torque under the sliding working condition.

[0068] As another feasible implementation manner, the determination process of the maximum allowed electric brake torque under the sliding working condition includes: based on the maximum recovery torque, speed and power generation efficiency of the braking motor, and the maximum allowed charging power of the power battery, determining the maximum allowed electric brake torque under the sliding working condition.

[0069] In some embodiments, the target electric brake torque is used to represent the electric brake torque value actually required to be output by the braking motor during the vehicle sliding braking process.

[0070] As a feasible implementation manner, the electric braking correction coefficient is a safety control coefficient (value range 0~1) derived based on real-time working condition parameters such as road slope, road adhesion coefficient, lateral acceleration, vehicle speed, etc., and the maximum allowed electric braking torque is dynamically scaled through multiplication operation, so that the target electric braking torque is adapted to the current working condition.

[0071] It should be understood that the maximum allowed electric braking torque in the coasting working condition defines the absolute safety upper limit of the braking motor, avoiding the torque output exceeding the bearing capacity of the braking motor and the battery; and the electric braking correction coefficient focuses on the dynamic adaptation of the real-time working condition, solving the braking safety and efficiency balance problem under different road surfaces and speed conditions. The combination of the two ensures the basic safety of the electric braking system and realizes the working condition-based precise control.

[0072] S303, based on the total braking torque of the vehicle and the target electric braking torque, determining a hydraulic compensation torque.

[0073] The total braking torque is used to reflect the total braking torque required by the vehicle in the current coasting working condition to achieve the expected deceleration effect (such as meeting the driver's braking intention, adapting to the road safety constraints, etc.), which is a core index for measuring braking intensity and directly determines the deceleration efficiency and safety redundancy of the vehicle.

[0074] As a feasible implementation manner, the determination process of the total braking torque includes: combining the real-time vehicle speed, road slope, safety distance from the front vehicle and other parameters, automatically determining the required coasting deceleration intensity through a preset algorithm, and then converting the deceleration intensity into the corresponding total braking torque according to the vehicle mass, braking system transmission efficiency and other parameters.

[0075] As another feasible implementation manner, the determination process of the total braking torque includes: determining the coasting deceleration requirement based on the vehicle speed; determining the total braking force of the vehicle based on the coasting deceleration requirement; and determining the total braking torque based on the total braking force and the conversion coefficient between braking force and braking torque.

[0076] The hydraulic compensation torque is used to represent the supplementary braking torque provided by the hydraulic execution unit when the target electric braking torque cannot meet the total braking torque requirement alone, which can fill the difference between the electric braking torque and the total braking torque without pedal intervention, ensuring the coasting deceleration effect and safety.

[0077] As a feasible implementation method, given the total braking torque and the target electric braking torque, when the target electric braking torque is less than the total braking torque (i.e., electric braking cannot independently meet the braking demand), the torque difference between the total braking torque and the target electric braking torque is directly used as the hydraulic compensation torque. The corresponding braking force is output through the hydraulic actuator to achieve coordinated compensation between electric braking and hydraulic braking. If the target electric braking torque is greater than or equal to the total braking torque, the hydraulic compensation torque is 0. In this case, the total braking demand can be met by electric braking alone. This ensures sufficient output of braking torque under coasting conditions, maximizes the energy recovery advantage of electric braking, and avoids increased energy consumption caused by additional hydraulic intervention, achieving a dual balance between efficiency and safety in the vehicle's coasting state.

[0078] As a feasible implementation method, in order to make full use of the brake motor for energy recovery, when the target electric braking torque is greater than or equal to the total braking torque, the target electric braking torque output by the brake motor is the total braking torque; when the target electric braking torque is less than the total braking torque, the target electric braking torque output by the brake motor is the corrected maximum permissible electric braking torque value under the coasting condition.

[0079] For example, the target electric braking torque can satisfy the following formula: ; in, This is the conversion coefficient between braking force and braking torque. Used to indicate total braking force. Used to indicate the maximum permissible electric braking torque value under modified coasting conditions. Used to indicate the target electric braking torque.

[0080] For example, the hydraulic compensation torque can satisfy the following formula: ; in, Used to indicate hydraulic compensation torque Used to indicate total braking torque Used to indicate the target electric braking torque, This is the conversion coefficient between braking force and braking torque.

[0081] S304. Based on the target electric braking torque and hydraulic compensation torque, brake control is performed on the vehicle.

[0082] As a feasible implementation method, after the vehicle braking control device issues a control command, the brake motor controller responds first, driving the brake motor to output electric braking force matching the target electric braking torque, while simultaneously recovering energy. The hydraulic control unit synchronously receives the hydraulic compensation torque command. If the hydraulic compensation torque is 0, the hydraulic actuator remains in standby mode, and braking is completed solely by electric braking. If the hydraulic compensation torque is greater than 0, the hydraulic control unit quickly converts the torque demand into wheel cylinder pressure control signals, driving the hydraulic actuator to precisely output the corresponding supplementary braking force. Furthermore, the intervention of the hydraulic braking force adopts a progressive loading logic to avoid a jerky feeling when superimposed with the electric braking force. Throughout the control process, the central controller collects the actual output torque of the brake motor and the wheel cylinder pressure feedback data of the hydraulic actuator in real time, dynamically correcting the control commands to ensure that the sum of the output torques of electric braking and hydraulic braking always equals the total braking torque, achieving smooth, efficient, and safe braking control under coasting conditions.

[0083] It should be understood that real-time monitoring of wheel slip ratio and vehicle stability during vehicle braking control is the core mechanism for ensuring braking safety. The dynamic feedback of both can promptly mitigate braking risks and ensure that the coordinated control of electric and hydraulic braking remains within safe limits. Wheel slip ratio, as a key reference factor for the hydraulic control unit to adjust braking force, directly reflects the wheel braking state: when the real-time monitored slip ratio exceeds a preset safety threshold (typically 15%~20%), it indicates that the wheels are approaching lock-up. At this point, a braking force adjustment strategy must be immediately triggered to rapidly reduce the electric braking torque and prevent complete wheel lock-up leading to vehicle loss of control. Simultaneously, the hydraulic control unit responds synchronously, dynamically fine-tuning the output intensity of the hydraulic compensation torque based on slip ratio feedback. Through the coordinated adaptation of electric and hydraulic braking, the wheel slip ratio is stabilized within a safe range, ensuring both braking effectiveness and vehicle driving stability.

[0084] By dynamically adjusting the electric braking correction coefficient based on road and speed information, the system specifically limits the target electric braking torque and energy recovery intensity. This mitigates risks such as wheel slippage and vehicle loss of control caused by excessive electric braking output in low-traction surfaces and curves, significantly improving the safety and stability of coasting braking. Simultaneously, through precise hydraulic torque compensation, the system ensures that the total braking torque always matches the coasting deceleration requirements even when the electric braking torque is constrained. This maintains braking performance and coasting smoothness while maximizing energy recovery benefits within safe limits.

[0085] In some embodiments, multiple electric braking correction coefficients can be determined using multiple road surface information and speed information, and one electric braking correction coefficient that can meet the current driving conditions of the vehicle can be selected from the multiple electric braking correction coefficients.

[0086] As a feasible implementation method, combined with Figure 3 ,like Figure 4 As shown, step S301 above can be specifically implemented as follows: S401. Based on the road slope, determine the first electric braking correction coefficient.

[0087] Among them, the first electric braking correction coefficient is used to quantify the influence of road slope on the maximum permissible electric braking torque that the brake motor can output under coasting conditions.

[0088] As a feasible approach, when a vehicle is coasting uphill, the energy recovery potential of electric braking is relatively small due to the resistance characteristics of the uphill section. At this time, the road slope has a limited impact on the actual output capacity of the brake motor, and there is no need to further reduce the maximum allowable electric braking torque. Therefore, the first electric braking correction coefficient can be directly set to 1 to ensure that the electric braking system can fully utilize its basic output capacity under this condition.

[0089] In an exemplary embodiment, when the vehicle is going uphill, the first electric braking correction factor is 1.

[0090] As another feasible approach, when a vehicle is coasting downhill, in order to prevent the vehicle from accelerating due to gravity and to prevent the brake motor from overheating and triggering the protection mode due to prolonged continuous operation (leading to a decrease in regenerative braking capacity), the maximum permissible electric braking torque under coasting conditions needs to be specifically limited to be lower than the maximum output torque corresponding to the peak capacity of the brake motor, so as to ensure braking safety and motor operation stability.

[0091] In an exemplary embodiment, when the vehicle is going downhill, a first electric braking correction coefficient is determined based on the road slope, vehicle speed, and a first mapping relationship.

[0092] The first mapping relationship is used to characterize the correspondence between the downhill slope, downhill speed, and electric braking correction coefficient. The first mapping relationship can be constructed through a large amount of real vehicle test data under downhill conditions and simulation analysis results of multiple scenarios, and can accurately cover the combination of different slopes (such as gentle slopes and steep slopes) and different speeds (such as low-speed coasting and high-speed coasting).

[0093] It should be understood that when the vehicle is going downhill, the first electric braking correction coefficient is less than 1. By scaling the maximum permissible electric braking torque under coasting conditions through the first electric braking correction coefficient, the electric braking torque can be safely adapted in downhill scenarios.

[0094] S402. Based on the road surface adhesion coefficient, determine the second electric braking correction coefficient.

[0095] The second electric braking correction coefficient is used to quantify the influence of the road surface adhesion coefficient on the maximum permissible electric braking torque output by the brake motor under coasting conditions.

[0096] As a feasible approach, when the road surface adhesion coefficient is high (such as dry asphalt road surface), the grip between the wheel and the road surface is strong, and the wheel is less likely to slip or lock up during braking. In this case, the road surface adhesion coefficient has a lower requirement for limiting the electric braking torque.

[0097] In the exemplary embodiment, when the road surface adhesion coefficient is greater than the preset road surface adhesion coefficient, the second electric braking correction coefficient is 1.

[0098] As another feasible approach, when the road surface adhesion coefficient is low (such as in rainy or icy conditions), the grip between the wheels and the road surface is weak, and the vehicle is prone to slippage and lock-up during braking. In such cases, it is necessary to adjust the electric braking torque to avoid exceeding the road surface adhesion limit. To prevent wheel slippage due to excessive electric braking torque and to ensure vehicle braking stability, it is necessary to limit the output torque of the brake motor and prioritize ensuring effective adhesion between the wheels and the road surface.

[0099] In an exemplary embodiment, when the road surface adhesion coefficient is less than or equal to a preset road surface adhesion coefficient, a second electric braking correction coefficient is determined based on the road surface adhesion coefficient and the second mapping relationship.

[0100] The second mapping relationship is used to characterize the correspondence between the vehicle's road surface adhesion coefficient and the electric braking correction coefficient. The second mapping relationship is constructed using data from a large number of low-adhesion road surfaces.

[0101] It should be understood that when the road surface adhesion coefficient is less than or equal to the preset road surface adhesion coefficient, the second electric braking correction coefficient is less than 1.

[0102] S403. Based on lateral acceleration, determine the third electric braking correction coefficient.

[0103] The third electric braking correction coefficient is used to quantify the influence of lateral acceleration on the maximum permissible electric braking torque output by the brake motor during coasting.

[0104] As a feasible approach, when the lateral acceleration of a vehicle is small (such as in straight-line coasting or gentle turning scenarios), the lateral forces on the vehicle are balanced and the driving posture is stable. At this time, the constraint requirement of lateral acceleration on electric braking torque is extremely low, and the vehicle's handling stability will not be affected by the output of electric braking.

[0105] In the exemplary embodiment, when the lateral acceleration is less than a preset acceleration threshold, the third electric braking correction coefficient is 1.

[0106] As another feasible approach, when significant lateral acceleration is detected in the vehicle (such as during sharp turns or continuous curves), the vehicle is in a state of lateral force imbalance. In this situation, excessive electric braking torque (especially when the torque distribution between the left and right wheels is uneven) can easily interfere with the vehicle's steering characteristics, leading to risks such as skidding and fishtailing. To prioritize vehicle lateral stability and avoid adverse effects of electric braking torque on driving posture, the maximum permissible electric braking torque under skidding conditions needs to be reduced. Furthermore, the hydraulic control unit should differentiate the electric braking torque limits for the left and right wheels (e.g., limiting the electric braking torque of the outer wheel based on the turning direction) to maintain lateral force balance through torque regulation.

[0107] In an exemplary embodiment, when the lateral acceleration is greater than or equal to a preset acceleration threshold, a third electric braking correction coefficient is determined based on the lateral acceleration and a third mapping relationship.

[0108] The third mapping relationship is used to characterize the quantitative correspondence between lateral acceleration and the third electric braking correction coefficient, and can be constructed through a large amount of real vehicle test and simulation data under cornering conditions.

[0109] It should be understood that when the lateral acceleration is greater than or equal to the preset acceleration threshold, the third electric braking correction coefficient is less than 1.

[0110] S404. Determine the electric braking correction coefficient based on the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking correction coefficient.

[0111] As a feasible implementation method, after determining the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking correction coefficient, in order to ensure that the electric braking torque output by the brake motor can simultaneously meet the safety constraints of multiple working conditions such as road slope, road adhesion coefficient, and lateral acceleration, that is, to adapt to the braking requirements of the slope scenario, avoid the risk of slippage on low-adhesion road surfaces, and ensure the lateral stability of the vehicle, it is necessary to select the minimum value from the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking correction coefficient as the electric braking correction coefficient.

[0112] It should be understood that by limiting the maximum permissible electric braking torque through the most stringent operating condition constraints (corresponding to the minimum correction coefficient), the electric braking system can always output torque under the safest boundary conditions among all key influencing factors. This fundamentally avoids braking risks caused by insufficient consideration of single operating condition parameters and achieves a balance between safety and efficiency in multiple scenarios.

[0113] In some embodiments, when determining the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking coefficient, a coasting deceleration requirement may be introduced, and the electric braking correction coefficient may be further determined by the coasting deceleration requirement.

[0114] As a feasible implementation method, combined with Figure 4 ,like Figure 5 As shown, step S404 above can be specifically implemented as follows: S501. Determine the coasting deceleration requirement based on vehicle speed.

[0115] As a feasible implementation method, coasting deceleration requirement is used to represent the target deceleration value set for a vehicle in a coasting state to balance safe driving and energy recovery efficiency.

[0116] In an exemplary embodiment, quantitative matching can be achieved by pre-constructing a MAP table (i.e., a multidimensional parameter mapping table) that maps vehicle speed to coasting deceleration requirements. The MAP table can be generated based on a large amount of coasting test data, covering the optimal coasting deceleration requirements corresponding to different vehicle speed ranges (such as low speed, medium speed, and high speed). When the vehicle is in a coasting state, it is only necessary to detect the current real-time vehicle speed to quickly query the corresponding coasting deceleration requirements from the MAP table, thereby achieving accurate retrieval.

[0117] It should be understood that, generally speaking, the higher the vehicle speed, the greater the required deceleration during coasting (e.g., a slightly larger deceleration is needed at high speeds to ensure a safe braking distance), to avoid insufficient braking response in emergencies due to excessive speed. Conversely, at low speeds, the required deceleration is smaller (even approaching zero) to reduce unnecessary energy consumption, balancing coasting smoothness and range efficiency. This relationship aligns with vehicle dynamics and adapts to safety and energy-saving requirements at different speeds.

[0118] S502. When the ratio between the required deceleration and the target deceleration is greater than or equal to the preset ratio, the fourth electric braking correction coefficient is determined based on the ratio and the fourth mapping relationship.

[0119] The target deceleration is the deceleration corresponding to the maximum permissible electric braking torque under coasting conditions.

[0120] The fourth mapping relationship is used to characterize the correspondence between the ratio between the coasting deceleration requirement and the target deceleration and the electric braking correction coefficient.

[0121] The preset ratio is greater than 1.

[0122] The ratio between the required coasting deceleration and the target deceleration is used to intuitively reflect the extent to which the current coasting deceleration requirement exceeds the maximum capacity of electric braking. The larger the ratio, the more difficult it is to meet the expected deceleration requirement by electric braking alone, and more reliance needs to be placed on hydraulic braking to compensate.

[0123] As a feasible implementation method, when the ratio between the required deceleration during coasting and the target deceleration is greater than or equal to the preset ratio, in order to ensure that the hydraulic actuator can respond quickly and output sufficient compensating braking force, and to avoid the hydraulic compensation being delayed due to excessive torque distribution occupied by electric braking, it is necessary to fine-tune the maximum allowable electric braking torque under the coasting condition through the fourth electric braking correction coefficient.

[0124] It should be understood that in scenarios with extremely high coasting deceleration requirements, slightly reducing the maximum permissible electric braking regenerative torque allows sufficient response space for the rapid intervention of hydraulic braking, prioritizing overall braking performance and safety.

[0125] As another feasible implementation method, when the ratio of the coasting deceleration demand to the target deceleration is less than the preset ratio, it means that the current maximum capacity of electric braking (corresponding to the target deceleration) can cover the coasting deceleration demand, and there is no need for additional hydraulic braking. At this time, the fourth electric braking correction coefficient is directly set to 1 to ensure that electric braking fully utilizes the energy recovery advantage.

[0126] In the exemplary embodiment, when the ratio between the coasting deceleration requirement and the target deceleration is less than a preset ratio, the fourth electric braking correction coefficient is 1.

[0127] It should be understood that when the coasting deceleration demand exceeds the deceleration that can be achieved by the current permissible electric braking alone (i.e., the ratio between the coasting deceleration demand and the target deceleration is greater than or equal to the preset ratio), the maximum permissible electric braking torque in the coasting condition is not necessarily directly limited by the coasting deceleration demand. Its core is still determined by the operating parameters such as road slope and adhesion coefficient. The portion of the total braking force demand that exceeds the electric braking capacity will be completely filled by hydraulic compensation torque, ultimately achieving a match between the total braking torque and the coasting deceleration demand.

[0128] S503. The minimum value among the first electric braking correction coefficient, the second electric braking correction coefficient, the third electric braking correction coefficient, and the fourth electric braking correction coefficient is determined as the electric braking correction coefficient.

[0129] As a feasible implementation method, after obtaining the first, second, third, and fourth electric braking correction coefficients, the coefficients are sorted by size using a built-in comparison algorithm, and the minimum value is directly extracted as the final output electric braking correction coefficient. This ensures that the coefficient can simultaneously respond to multi-dimensional constraints such as road slope, adhesion coefficient, lateral acceleration, and deceleration requirements.

[0130] It should be understood that determining the minimum value among the first, second, third, and fourth electric braking correction coefficients as the electric braking correction coefficient essentially defines the safe output boundary of the electric braking torque through the most stringent operating condition constraints (corresponding to the minimum correction coefficient). Regardless of whether it's a single operating condition (such as a low-adhesion road surface) or multiple operating conditions combined (such as high-speed downhill turning), the most conservative correction strategy ensures that the electric braking torque does not exceed any safety constraint. This avoids braking risks caused by insufficient consideration of a certain parameter while maximizing energy recovery space under safe conditions, achieving a balance between braking safety and efficiency under multiple operating conditions.

[0131] By accurately matching the coasting deceleration requirement with the vehicle speed, and then dynamically responding to the difference between the coasting deceleration requirement and the maximum electric braking capacity through the fourth mapping relationship, the minimum value among the first, second, third, and fourth electric braking correction coefficients is used as the electric braking correction coefficient. This covers the constraints of working conditions such as slope, adhesion coefficient, and lateral acceleration, while also taking into account the torque adaptation of the coasting deceleration requirement. This ensures that the electric braking torque is always within the safety boundary, avoiding risks such as wheel slippage and vehicle loss of control, and maximizing the retention of energy recovery efficiency while meeting deceleration requirements. This achieves a balance between braking safety and performance under multiple working conditions.

[0132] In some embodiments, after determining the electric braking correction coefficient, the maximum permissible electric braking torque for coasting conditions can be determined by parameters such as the maximum recovery torque and speed of the brake motor.

[0133] As a feasible approach, the process of determining the maximum permissible electric braking torque under coasting conditions includes: determining the maximum permissible electric braking torque under coasting conditions based on the maximum regenerative torque, speed, power generation efficiency of the brake motor, and the maximum permissible charging power of the power battery.

[0134] Among them, the maximum regenerative torque is used to represent the maximum regenerative braking torque that the brake motor can stably output within the safe operating range (not exceeding the mechanical strength and temperature thresholds). It is the core mechanical constraint upper limit of the maximum permissible electric braking torque under coasting conditions. The maximum permissible electric braking torque under coasting conditions must not exceed the maximum regenerative torque of the brake motor, otherwise it will cause the motor to be overloaded and damaged or trigger thermal protection.

[0135] Rotational speed is used to represent the real-time rotational speed of the brake motor when the vehicle is coasting (positively correlated with vehicle speed), which directly affects the motor's torque output characteristics and power generation capacity. Within a certain speed range, the brake motor can output electric braking torque close to the maximum regenerative torque; when the speed exceeds the critical value, the motor output torque will decrease as the speed increases. Therefore, it is necessary to dynamically adjust the maximum allowable electric braking torque under coasting conditions according to the real-time speed to adapt to the motor speed and torque characteristics.

[0136] Power generation efficiency is used to indicate the efficiency of the brake motor in converting the vehicle's kinetic energy into electrical energy (affected by factors such as speed, torque, and motor temperature). The higher the power generation efficiency, the more electrical energy is recovered under the same electric braking torque. When the power generation efficiency is too low (such as in low-speed, low-torque conditions), maintaining a high electric braking torque will result in insufficient energy recovery and increased motor losses. Therefore, it is necessary to optimize the maximum allowable electric braking torque under coasting conditions in combination with power generation efficiency to balance recovery efficiency and motor losses.

[0137] The maximum permissible charging power of a power battery indicates the maximum charging power that the battery can safely receive under its current conditions (such as charge level and temperature), and it is a core constraint for energy recovery. The power generation corresponding to the electric braking torque (positively correlated with motor speed and torque) must not exceed the maximum permissible charging power of the power battery; otherwise, it will lead to battery overcharging, overheating, and safety risks. Therefore, the maximum permissible electric braking torque under coasting conditions must be limited by this parameter to ensure that the power generation is always within the battery's safe charging range.

[0138] As a feasible approach, the maximum permissible electric braking torque on the motor side is calculated based on the maximum regenerative torque, real-time speed, and power generation efficiency of the braking motor; the maximum permissible electric braking torque on the battery side is calculated based on the maximum permissible charging power of the power battery, the real-time speed of the motor, and power generation efficiency; finally, the permissible torque on the motor side is compared with the permissible torque on the battery side, and the minimum value of the two is taken as the final maximum permissible electric braking torque under coasting conditions, ensuring that both motor mechanical constraints and battery charging constraints are met simultaneously.

[0139] As another feasible approach, the electric braking torque that the power battery can support is determined based on the rotational speed, power generation efficiency, and maximum allowable charging power; the smaller value between the maximum recovery torque and the electric braking torque that the power battery can support is determined as the maximum allowable electric braking torque under coasting conditions.

[0140] It should be understood that determining the maximum permissible electric braking torque under coasting conditions by comprehensively considering the maximum regenerative torque, speed, power generation efficiency of the braking motor, and the maximum permissible charging power of the power battery serves two purposes: firstly, it avoids risks such as motor overload and battery overcharging from the root by verifying both the mechanical limits of the motor and the safety of battery charging, thus ensuring the operational stability of the braking control device and core components; secondly, it maximizes energy recovery benefits within the safety boundary through dynamic adaptation of power generation efficiency, while reducing motor losses in inefficient recovery scenarios, thus balancing braking safety, component durability, and energy recovery efficiency, and adapting to the actual needs of dynamic parameter changes under coasting conditions.

[0141] In an exemplary embodiment, such as Figure 6 As shown, determining the maximum permissible electric braking torque under coasting conditions specifically includes the following steps: S601. Based on rotational speed, power generation efficiency, and maximum allowable charging power, determine the electric braking torque that the power battery can support.

[0142] As a feasible implementation method, the maximum electrical power that the power battery can receive and the power generation of the braking motor, along with the electric braking torque, speed, and power generation efficiency, satisfy the formula "Power generation = Electric braking torque × Speed ​​ / (9550 × Power generation efficiency)". Therefore, the electric braking torque that the power battery can support can be derived in reverse, ensuring that the power generation corresponding to the electric braking output of the motor does not exceed the maximum allowable charging power of the battery, thus avoiding the risk of battery overcharging.

[0143] For example, the electric braking torque can satisfy the following formula: Electric braking torque = ; Pebatt represents the maximum allowable charging power; Motspd represents the rotational speed. Used to indicate power generation efficiency; 9550 is a unit conversion constant based on torque, power, and speed.

[0144] S602. The smaller of the maximum recovery torque and the electric braking torque that the power battery can support is determined as the maximum permissible electric braking torque under coasting conditions.

[0145] As a feasible approach, when the electric braking torque supported by the power battery exceeds the maximum regenerative braking torque of the motor, the mechanical strength of the motor becomes a bottleneck. In this case, the maximum regenerative braking torque is used as the upper limit to avoid motor overload. Conversely, when the electric braking torque supported by the power battery is less than the maximum regenerative braking torque, battery charging safety becomes a constraint. In this case, the allowable torque on the battery side is used as the upper limit to avoid overcharging. The combination of these two approaches ensures that the maximum permissible electric braking torque during coasting conditions simultaneously satisfies both motor mechanical safety and battery charging safety.

[0146] For example, the maximum permissible electric braking torque under coasting conditions can satisfy the following formula: Tmax_regen1=min(Tmmin, ); Where Tmax_regen1 represents the maximum permissible electric braking torque under coasting conditions; Tmmin represents the maximum regenerative braking torque.

[0147] In some embodiments, when determining the maximum permissible electric braking torque for coasting conditions, the total braking torque required by the vehicle can be determined based on the vehicle's coasting deceleration requirements.

[0148] As a feasible implementation method, such as Figure 7 As shown, the process of determining the total braking torque includes the following steps: S701, Determine the coasting deceleration requirement based on vehicle speed.

[0149] S702. Determine the total braking force of the vehicle based on the coasting deceleration requirements.

[0150] As a feasible approach, the total braking force requirement can be directly quantified by multiplying mass and acceleration.

[0151] For example, the total braking force can satisfy the following formula: ; in, Used to indicate the required gliding deceleration; Used to indicate total braking force; Used to indicate the mass of a vehicle.

[0152] It should be understood that the greater the demand for coasting deceleration and the greater the vehicle mass, the greater the total braking force required. From a physical perspective, it is necessary to ensure that the braking force can support the expected deceleration effect and provide a quantitative benchmark for subsequent braking torque calculation.

[0153] S703. Determine the total braking torque based on the total braking force and the conversion coefficient between the braking force and the braking torque.

[0154] As a feasible approach, the total braking torque is calculated by multiplying the total braking force by the conversion coefficient.

[0155] For example, the total braking torque can satisfy the following formula: ; in, This is the conversion coefficient between braking force and braking torque. Used to indicate total braking force.

[0156] It should be understood that the conversion coefficient k is essentially a quantification of the mechanical characteristics of the braking system (including a comprehensive mapping of parameters such as the effective rolling radius of the wheel, the lever arm relationship between the brake shoe / brake disc and the wheel, and the efficiency of the transmission mechanism). By converting the total braking force into the total braking torque through the conversion coefficient, the abstract deceleration requirement is ultimately translated into a torque command that the braking actuators (electric brake motor, hydraulic actuator) can directly respond to, thus achieving a closed-loop quantification from requirement to execution.

[0157] The following describes some specific braking control methods for vehicles coasting under several typical operating conditions.

[0158] In some embodiments, based on the configuration parameters of a pure electric SUV (equipped with a permanent magnet synchronous brake motor, peak braking torque 1200N) m; The hydraulic control unit includes an electro-hydraulic booster and an ESP vehicle stability system; it is equipped with a rain sensor, a slope sensor, a longitudinal / lateral acceleration sensor, and a brake pedal travel sensor); based on typical operating conditions, the following is the control logic and execution process for braking on flat roads in heavy rain: The vehicle is traveling at 80 km / h on a flat, sunny road, in a light braking and coasting state (coasting deceleration requirement 0.15g). At this time, the lateral acceleration is 0.005g (approaching a straight-line driving state), and the yaw rate is 0.5° / s (slight yaw due to torque distribution differences, within the normal range). The rain sensor detects heavy rain (10 mm / h), classifying it as a low-traction condition (i.e., the road surface adhesion coefficient is less than or equal to the preset road surface adhesion coefficient).

[0159] Calculate the target electric braking torque: Under clear weather conditions, based on the initial parameters, the target electric braking torque is 100% of the peak torque of the brake motor, i.e., 1200N. m; Under heavy rain and low-adhesion conditions, according to the logic of the second electric braking correction coefficient (the electric braking torque needs to be limited on low-adhesion surfaces to avoid slippage), the correction coefficient is taken as 0.5, and the corresponding limited electric braking torque is 50% × 1200 N. m=600N m; Considering the total braking torque requirement, the target electric braking torque is the minimum of the limit value and the total requirement, i.e., Tm_cmd = min(800N). m, 600N m)=600N m.

[0160] Calculate the hydraulic compensation torque: The hydraulic compensation torque is the difference between the total braking torque and the target electric braking torque, i.e., T_hyd_comp = 800N. m-600N m=200N m.

[0161] Brake motor responds to command output of 600N m electric braking torque, simultaneously achieving 40kW energy recovery; e-booster drives the hydraulic actuator to output 200N. The hydraulic compensation torque works in conjunction with the electric braking; real-time monitoring shows that the wheel slip rate is always within the safe threshold (no tire slippage), the actual deceleration is stably maintained at 0.15g, and there are no abnormal fluctuations in lateral acceleration and yaw rate, ensuring the driving safety of vehicles and personnel under heavy rain conditions.

[0162] As a feasible implementation method, based on the configuration parameters of a pure electric SUV and combined with typical scenario requirements, the following is the control logic and execution process for a long steep downhill slope: The initial state of the vehicle is: speed 60km / h, downhill in sunny weather (slope 10%), straight driving, brake pedal not triggered (coasting condition), and constant speed downhill is required through braking control to prevent the brake motor from overheating.

[0163] Determine the maximum permissible electric braking torque under coasting conditions: Based on the downhill gradient parameters and according to the logic of the first electric braking correction coefficient (for long downhill slopes, the electric braking torque needs to be limited to balance the motor load), the correction coefficient is taken as 0.6, corresponding to a maximum permissible electric braking torque of 60% × 1200 N after limitation. m=720N m.

[0164] Determine the target electric braking torque and hydraulic compensation torque: Based on the slope dynamics model, the total braking torque required to maintain a constant speed of 60 km / h downhill is 900 N. m; The target electric braking torque is the minimum of the total braking torque and the modified maximum permissible electric braking torque under coasting conditions, i.e., Tm_cmd = min(900N). m, 720N m)=720N m; The hydraulic compensation torque is the difference between the total braking torque and the target electric braking torque, i.e., T_hyd_comp = 900N. m-720N m=180N m.

[0165] Brake motor output 720N The electric braking torque is 180N, synchronously output by the hydraulic control unit (e-booster + ESP). m hydraulic compensation torque; the central controller monitors the brake motor temperature in real time, with a preset protection threshold of 120°C (when exceeded, Tmax_regen is reduced to 50%). In actual operation, the motor temperature is stable at 110°C, and overheat protection is not triggered; execution effect: the vehicle always descends at a constant speed of 60km / h, meeting the safe coasting requirements of long downhill slopes, while balancing the motor load through torque distribution to avoid overheating risks.

[0166] As a feasible implementation method, based on the configuration parameters of a pure electric SUV and combined with typical scenario requirements, the following is the control logic and execution process of high-speed cornering braking: The initial state of the vehicle is: speed 100km / h, flat road in clear weather, steering wheel angle 120° (corresponding to lateral acceleration ay=0.45g), in a medium-intensity coasting braking state (coasting deceleration requirement 0.3g), and the lateral stability of the vehicle must be prioritized.

[0167] Determine the maximum permissible electric braking torque under coasting conditions: Based on the lateral acceleration parameter (0.45g is greater than or equal to the preset acceleration threshold), and according to the logic of the third electric braking correction coefficient (electric braking torque needs to be limited in corners to avoid interfering with steering stability), the correction coefficient is set to 0.7, corresponding to a maximum permissible electric braking torque of 70% × 1200 N after limitation. m=840N m.

[0168] Determine the target electric braking torque and hydraulic compensation torque: Based on deceleration requirements and vehicle dynamics model, the required total braking torque is 1000 N. m; The target electric braking torque is the minimum of the total braking torque and the modified maximum permissible electric braking torque under coasting conditions, i.e., Tm_cmd = min(1200N). m, 840N m)=840N m; The hydraulic compensation torque is the difference between the total braking torque and the target electric braking torque, i.e., T_hyd_comp = 1000N. m-840N m=160N m.

[0169] Brake motor output 840N The electric braking torque is adjusted by the ESP system to differentiate the hydraulic compensation torque (60N for the left front wheel). m, right front wheel 100N m), adapted to the force characteristics of cornering; real-time monitoring shows: yaw rate deviation is less than 0.5° / s, no understeer or oversteer occurs, and lateral acceleration is stable within a safe range; execution effect: while meeting the 0.3g coasting deceleration requirement, torque limiting and differentiated distribution ensure high-speed cornering stability.

[0170] In some embodiments, such as Figure 8 As shown, the vehicle braking control method can be specifically implemented through the following steps: S801, The vehicle begins to coast. Proceed to steps S802 and S804.

[0171] S802, Obtain road surface information and speed information.

[0172] S803. Based on road surface information and speed information, determine the target electric braking torque. Jump to step S805.

[0173] S804. Determine the total braking torque. Jump to step S805.

[0174] S805. Based on the target electric braking torque and the total braking torque, determine the hydraulic compensation torque. Jump to steps S806 and S807.

[0175] S806, Hydraulic compensation torque control brake motor. Jump to step S808.

[0176] S807, Hydraulic actuator based on hydraulic compensation torque control.

[0177] S808. Detect whether the vehicle's driving conditions have changed; if yes, proceed to step S802; if no, proceed to step S809.

[0178] S809, End.

[0179] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of the electronic device disclosed in an embodiment of this application. The electronic device 900 may include a processor 901 and a memory 902. The processor 901 and the memory 902 are communicatively connected. The memory 902 is used to store programs, and the processor 901 is used to execute programs, specifically performing the relevant steps described above in the embodiment of the vehicle braking control method.

[0180] Specifically, the program may include program code, which includes computer-executable instructions. Memory 902 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device. Processor 901 may be a central processing unit (CPU), a microcontroller unit (MCU), or an application-specific integrated circuit (ASIC).

[0181] This application also provides a computer-readable storage medium storing at least one executable instruction that, when executed on a vehicle braking control device, causes the vehicle braking control device to perform the vehicle braking control method in any of the above method embodiments.

[0182] This application provides a computer program product that can be executed by the processor 901 of an electronic device 900 to perform the vehicle braking control method in the above embodiments.

[0183] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art can understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this application still fall within the scope of this application.

Claims

1. A vehicle braking control method, characterized in that, The vehicle braking control method includes: When the vehicle is in a coasting state, an electric braking correction coefficient is determined based on the vehicle's road surface information and speed information; the road surface information is used to characterize the parameter values ​​of road surface parameters that affect braking performance. Based on the electric braking correction coefficient and the maximum permissible electric braking torque of the brake motor under coasting conditions, the target electric braking torque of the vehicle is determined. The hydraulic compensation torque is determined based on the vehicle's total braking torque and the target electric braking torque; The vehicle is braked based on the target electric braking torque and the hydraulic compensation torque.

2. The vehicle braking control method according to claim 1, characterized in that, The road surface information includes: road surface slope and road surface adhesion coefficient; the speed information includes: lateral acceleration; the determination of the electric braking correction coefficient based on the vehicle's road surface information and speed information includes: Based on the road surface slope, a first electric braking correction coefficient is determined; Based on the road surface adhesion coefficient, determine the second electric braking correction coefficient; Based on the aforementioned lateral acceleration, the third electric braking correction coefficient is determined; The electric braking correction coefficient is determined based on the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking correction coefficient.

3. The vehicle braking control method according to claim 2, characterized in that, The speed information also includes: vehicle speed; determining the first electric braking correction coefficient based on the road surface slope includes: When the vehicle is going downhill, the first electric braking correction coefficient is determined based on the road slope, the vehicle speed, and the first mapping relationship; the first mapping relationship is used to characterize the correspondence between the downhill slope, the downhill speed, and the electric braking correction coefficient.

4. The vehicle braking control method according to claim 2, characterized in that, The determination of the second electric braking correction coefficient based on the road surface adhesion coefficient includes: When the road surface adhesion coefficient is less than or equal to the preset road surface adhesion coefficient, the second electric braking correction coefficient is determined based on the road surface adhesion coefficient and the second mapping relationship; the second mapping relationship is used to characterize the correspondence between the road surface adhesion coefficient and the electric braking correction coefficient of the vehicle.

5. The vehicle braking control method according to claim 2, characterized in that, The determination of the third electric braking correction coefficient based on the lateral acceleration includes: When the lateral acceleration is greater than or equal to a preset acceleration threshold, the third electric braking correction coefficient is determined based on the lateral acceleration and the third mapping relationship; the third mapping relationship is used to characterize the correspondence between the lateral acceleration of the vehicle and the electric braking correction coefficient.

6. The vehicle braking control method according to claim 2, characterized in that, The speed information further includes: vehicle speed; determining the electric braking correction coefficient based on the first electric braking correction coefficient, the second electric braking correction coefficient, and the third electric braking correction coefficient includes: Based on the vehicle speed, determine the required coasting deceleration; If the ratio between the required gliding deceleration and the target deceleration is greater than or equal to a preset ratio, a fourth electric braking correction coefficient is determined based on the ratio and the fourth mapping relationship. The minimum value among the first electric braking correction coefficient, the second electric braking correction coefficient, the third electric braking correction coefficient, and the fourth electric braking correction coefficient is determined as the electric braking correction coefficient; Wherein, the target deceleration is the deceleration corresponding to the maximum permissible electric braking torque under the coasting condition; the fourth mapping relationship is used to characterize the correspondence between the ratio between the coasting deceleration requirement and the target deceleration and the electric braking correction coefficient; the preset ratio is greater than 1.

7. The vehicle braking control method according to claim 6, characterized in that, The first electric braking correction factor is 1 when the vehicle is going uphill; The second electric braking correction coefficient is 1 when the road surface adhesion coefficient is greater than the preset road surface adhesion coefficient; The third electric braking correction coefficient is 1 when the lateral acceleration is less than the preset acceleration threshold. The fourth electric braking correction coefficient is 1 if the ratio between the coasting deceleration requirement and the target deceleration is less than a preset ratio.

8. The vehicle braking control method according to any one of claims 1-7, characterized in that, The process for determining the maximum permissible electric braking torque under the coasting condition includes: The maximum permissible electric braking torque for the coasting condition is determined based on the maximum recovery torque, speed, power generation efficiency of the brake motor, and the maximum permissible charging power of the power battery.

9. The vehicle braking control method according to claim 8, characterized in that, The determination of the maximum permissible electric braking torque under the coasting condition based on the maximum regenerative torque, speed, power generation efficiency of the brake motor, and the maximum permissible charging power of the power battery includes: Based on the rotational speed, the power generation efficiency, and the maximum allowable charging power, the electric braking torque that the power battery can support is determined. The smaller of the maximum recovery torque and the electric braking torque that the power battery can support is determined as the maximum permissible electric braking torque under coasting conditions.

10. The vehicle braking control method according to any one of claims 1-7, characterized in that, The speed information includes: vehicle speed; the process of determining the total braking torque includes: The required coasting deceleration is determined based on the vehicle speed. Based on the aforementioned coasting deceleration requirement, the total braking force of the vehicle is determined; The total braking torque is determined based on the total braking force and the conversion coefficient between the braking force and the braking torque.

11. A vehicle braking control device, characterized in that, The vehicle braking control device includes: a determination module and a control module; The determining module is used to determine an electric braking correction coefficient based on the vehicle's road surface information and speed information when the vehicle is in a coasting state; the road surface information is used to characterize the parameter values ​​of road surface parameters that affect braking performance; the target electric braking torque of the vehicle is determined based on the electric braking correction coefficient and the maximum permissible electric braking torque of the brake motor under coasting conditions; and the hydraulic compensation torque is determined based on the vehicle's total braking torque and the target electric braking torque. The control module is used to perform braking control on the vehicle based on the target electric braking torque and the hydraulic compensation torque.

12. A vehicle, characterized in that, It includes a vehicle body, data acquisition equipment, a brake motor, a hydraulic actuator, and a vehicle braking control device as described in claim 11.

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