Vehicle brake control method, device, electronic control unit, medium and vehicle

Abstract

The application provides a vehicle braking control method, device, electronic control unit, medium and vehicle, and relates to the technical field of vehicle braking control. The control method is applied to an electronic control unit in a vehicle, the vehicle further comprises a driving motor and a power battery, and the method comprises the following steps: in the process of vehicle driving, the current state of charge and the current single body temperature of the power battery are acquired; based on a preset mapping relationship representing the maximum regenerative power of the power battery under different states of charge and different single body temperatures, the maximum allowed regenerative power corresponding to the current battery state is determined; based on a pre-calibrated vehicle speed-power mapping relationship, a target limit vehicle speed corresponding to the maximum allowed regenerative power is determined; and the vehicle is controlled to drive at a speed not higher than the target limit vehicle speed, thereby effectively improving the problem of unstable braking force fluctuation and braking effect caused by the limited energy regenerative power due to the high state of charge or low temperature of the battery, and significantly improving the functional safety level and operation reliability of the system.

Description

Technical Field

[0001] This application relates to the field of vehicle braking control technology, and in particular to a vehicle braking control method, device, electronic control unit, medium, and vehicle. Background Technology

[0002] With the rapid development of autonomous driving and intelligent connected vehicle technologies, driverless vehicles are increasingly being used in specific scenarios such as sanitation, logistics, and shuttle services. Low-speed operating vehicles, such as unmanned sweepers and unmanned logistics vehicles, are important representatives of this field, and their operational safety is the primary prerequisite for industrial implementation. As the last line of defense for vehicle active safety, the reliability and stability of the braking system's control strategy directly determine whether the vehicle can be safely and efficiently put into actual operation. Therefore, achieving the optimal balance between system cost and maintenance convenience while meeting stringent safety standards has become a core challenge that urgently needs to be addressed in this field.

[0003] In related technologies, to address the aforementioned challenges, a simplified braking scheme that eliminates hydraulic pressure is typically adopted for specific scenarios with low operating speeds (usually not exceeding 20 km / h). The core of this scheme lies in abandoning traditional hydraulic braking or complex electronic hydraulic braking (EHB) systems, instead employing drive motor reverse drag braking (i.e., regenerative braking) as the sole means of achieving conventional service braking. Specifically, when the vehicle needs to decelerate, the vehicle controller switches the drive motor from electric mode to generator mode. At this time, under the vehicle's inertia, the wheels rotate through the transmission system, driving the motor rotor to rotate. The motor generates a reverse electromagnetic torque (i.e., braking torque) opposite to the direction of rotation. This torque is fed back to the drive wheels through the transmission chain (such as a chain or reducer), thereby decelerating the vehicle and simultaneously converting some kinetic energy into electrical energy fed back to the power battery. Furthermore, this scheme is usually equipped with an independent electromagnetic parking brake (often integrated into the motor end cover or axle) for static parking and as an emergency backup in case of service brake failure. However, this scheme suffers from unstable braking performance. Summary of the Invention

[0004] The vehicle braking control method, device, electronic control unit, medium, and vehicle provided in this application are intended to improve the problem of unstable braking performance.

[0005] In a first aspect, this application provides a vehicle braking control method applied to an electronic control unit in a vehicle, the vehicle further including a drive motor and a power battery, the method comprising:

[0006] During vehicle operation, the current state of charge and current individual cell temperature of the power battery are obtained;

[0007] Based on a preset mapping relationship characterizing the maximum recharge power of the power battery under different states of charge and different cell temperatures, the maximum allowable recharge power corresponding to the current state of charge and current cell temperature is determined.

[0008] Based on the pre-calibrated vehicle speed-power mapping relationship, the target limit vehicle speed corresponding to the maximum allowable recharge power is determined. The vehicle speed-power mapping relationship is calibrated based on the external characteristics of the drive motor's reverse drag braking power supply and is used to define the maximum power supply that the drive motor can generate when performing maximum capacity reverse drag braking at different vehicle speeds.

[0009] Control the vehicle to travel at a speed not exceeding the target speed limit.

[0010] In one possible implementation, the target speed limit corresponding to the maximum allowable recharge power is determined based on a pre-calibrated speed-power mapping relationship, including: querying the speed-power mapping relationship to obtain the maximum power supply value that is less than or equal to the maximum allowable recharge power; and determining the speed corresponding to the maximum power supply value as the target speed limit.

[0011] In one possible implementation, controlling the vehicle to travel at a speed not exceeding a target speed limit includes: generating and outputting a speed limit command based on the target speed limit, so that the actual speed of the vehicle is controlled below the target speed limit.

[0012] In one possible implementation, before controlling the vehicle to travel at a speed not exceeding the target limit speed, the method further includes: determining, based on the external characteristics of the drive motor's anti-drag braking power supply, the vehicle's curb weight, and the transmission system efficiency, the theoretical braking distance from the target limit speed to a stop when performing maximum capacity anti-drag braking at the target limit speed; if the theoretical braking distance is greater than a preset safe braking distance threshold, iteratively lowering the target limit speed and re-determining the corresponding theoretical braking distance until the theoretical braking distance is not greater than the safe braking distance threshold; and using the speed that satisfies the condition that the theoretical braking distance is not greater than the safe braking distance threshold as the target limit speed for control.

[0013] In one possible implementation, the preset mapping relationship characterizing the maximum recharge power of the power battery under different states of charge and different cell temperatures, and the pre-calibrated vehicle speed-power mapping relationship are based on the parameter calibration of the drive motor and the power battery that meet the system matching conditions. The system matching conditions include: the maximum DC power output of the drive motor under anti-drag braking conditions is less than the minimum continuous recharge power of the power battery in all states of charge and operating temperature ranges.

[0014] In one possible implementation, the vehicle also includes an electromagnetic brake, and the vehicle braking control method further includes an emergency braking step: when the reverse drag braking function of the drive motor is detected to be ineffective and the current vehicle speed is lower than a preset emergency braking activation speed threshold, the electromagnetic brake is triggered to perform emergency braking.

[0015] In one possible implementation, triggering the electromagnetic brake for emergency braking includes: determining the upper limit of the number of emergency braking triggers allowed per unit time or unit mileage based on the vehicle's designed total lifespan or total mileage and the electromagnetic brake's calibrated emergency braking usage lifespan; and executing the triggering of the electromagnetic brake for emergency braking when the actual number of emergency braking triggers in the current cycle does not exceed the upper limit.

[0016] Secondly, this application provides a vehicle braking control device, applied to an electronic control unit in a vehicle, the vehicle further including a drive motor and a power battery, the device comprising:

[0017] The acquisition module is used to acquire the current state of charge and current cell temperature of the power battery during vehicle operation.

[0018] The first determining module is used to determine the maximum allowable recharge power corresponding to the current state of charge and the current cell temperature based on a preset mapping relationship that characterizes the maximum recharge power of the power battery under different states of charge and different cell temperatures.

[0019] The second determining module is used to determine the target limiting vehicle speed corresponding to the maximum allowable recharge power based on the pre-calibrated vehicle speed-power mapping relationship. The vehicle speed-power mapping relationship is calibrated based on the external characteristics of the reverse drag braking power supply of the drive motor and is used to define the maximum power supply that the drive motor can generate when performing maximum reverse drag braking at different vehicle speeds.

[0020] The control module is used to control the vehicle to travel at a speed not exceeding the target speed limit.

[0021] Thirdly, this application provides an electronic control unit, including: a processor, and a memory communicatively connected to the processor;

[0022] Memory is used to store instructions executed by the computer;

[0023] A processor for executing computer-executable instructions stored in memory to implement any of the methods of the first aspect.

[0024] Fourthly, this application provides a vehicle including an electronic control unit as described in the third aspect.

[0025] Fifthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed, are used to implement the method of any one of the first aspects.

[0026] Sixthly, this application provides a computer program product, including a computer program that, when executed, implements the method of any one of the first aspects.

[0027] The vehicle braking control method, device, electronic control unit, medium, and vehicle provided in this application are applied to the electronic control unit in a vehicle, which also includes a drive motor and a power battery. The method includes: acquiring the current state of charge and current cell temperature of the power battery during vehicle operation; determining the maximum allowable recharge power corresponding to the current state of charge and current cell temperature based on a preset mapping relationship characterizing the maximum recharge power of the power battery at different states of charge and different cell temperatures; determining the target speed limit corresponding to the maximum allowable recharge power based on a pre-calibrated speed-power mapping relationship, wherein the speed-power mapping relationship is calibrated based on the external characteristics of the drive motor's anti-drag braking power supply and is used to define the maximum power supply that the drive motor can generate when performing maximum anti-drag braking at different vehicle speeds; and controlling the vehicle to travel at a speed not exceeding the target speed limit.

[0028] During this process, by monitoring the state of charge (SOC) and individual cell temperature of the power battery in real time, and based on the preset battery state-maximum recharge power mapping relationship, the maximum allowable recharge power of the power battery under the current operating conditions is dynamically determined. Combined with the pre-calibrated vehicle speed-power mapping relationship, the power limit is accurately converted into the corresponding target speed limit, and the vehicle is ultimately controlled to travel within the range not exceeding this speed. This effectively improves the safety hazards of braking force fluctuations and unstable braking effects caused by the limited energy recharge power due to the high state of charge or low temperature of the battery when using motor reverse drag as the main braking scheme. Through the dynamic speed limiting strategy, the maximum braking power required by the vehicle is ensured from the source to always not exceed the real-time receiving capacity of the power battery. Thus, in a low-cost architecture without a traditional hydraulic braking system, the risk of braking force attenuation caused by the high state of charge (SOC) or low temperature of the battery can be effectively eliminated, thereby providing stable, reliable and predictable braking performance for the vehicle under all operating conditions, and significantly improving the functional safety level and operational reliability of the system. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0030] Figure 1A schematic flowchart of a vehicle braking control method provided as an exemplary embodiment of this application;

[0031] Figure 2 A schematic diagram of a vehicle braking control device provided as an exemplary embodiment of this application;

[0032] Figure 3 A schematic diagram of the structure of an electronic control unit provided as an exemplary embodiment of this application.

[0033] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0034] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0035] The terms “first,” “second,” etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, products, or apparatus.

[0036] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with relevant laws, regulations and standards, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0037] The working principle of the braking system in related technologies specifically includes the following three aspects: 1) Service braking: The reverse drag braking of the drive motor is the only way to achieve conventional service braking. When the vehicle needs to decelerate, the drive motor switches to the power generation mode to generate reverse electromagnetic torque. This torque is directly transmitted to the left and right rear wheels of the vehicle through the chain transmission mechanism, thereby achieving vehicle deceleration. 2) Parking braking: An electromagnetic brake (electromagnetic brake) is used to achieve static parking function. This electromagnetic brake is integrated and installed on the rear end cover of the drive motor. Its braking force is also applied to the left and right rear wheels through the aforementioned chain transmission mechanism to achieve reliable parking. 3) Emergency braking: During driving, if the reverse drag braking function of the drive motor is detected to fail, the control system immediately cuts off the power supply to the electromagnetic brake to lock it. The friction torque of the electromagnetic brake is used to achieve emergency braking as a safety backup for the service braking.

[0038] However, in the aforementioned technical solution that uses a drive motor for reverse braking as the main braking source, the output capability of its braking torque is not autonomously controllable, but rather deeply coupled and strictly limited by the real-time operating state of the power battery. Specifically, when the power battery is at a high SOC, its acceptable charging power drops sharply to reduce the risk of overcharging; when the temperature of a single power battery cell is too low, its internal chemical reaction rate slows down, and the maximum recharge power capability is also significantly limited. Under these two typical operating conditions, the power battery cannot absorb all the electrical energy that the drive motor attempts to regenerate during braking. To protect the power battery, the power generation of the drive motor must be forcibly limited. This directly leads to the passive weakening or even interruption of the reverse torque (i.e., effective braking force) generated by the drive motor, resulting in unpredictable and drastic fluctuations in the vehicle's braking performance. The braking distance becomes unstable and difficult to guarantee, especially in dangerous situations requiring emergency braking, posing a significant safety hazard. At the same time, as a safety redundancy, the electromagnetic brake's dynamic response speed and continuous braking torque are usually limited, making it difficult to independently undertake stable and effective emergency braking tasks at high vehicle speeds or with large inertia.

[0039] To address the aforementioned issues, this application provides a vehicle braking control scheme. By real-time sensing of the battery's state of charge (SOC) and individual cell temperature during vehicle operation, and dynamically determining the upper limit of power the battery can safely receive under current operating conditions based on a preset battery state-maximum recharge power mapping relationship, this scheme uses a pre-calibrated speed-power mapping relationship based on the drive motor's external characteristics to proactively convert this power limit into a precisely matched maximum permissible speed—the target speed limit. By actively constraining the vehicle's speed to this dynamically determined safe speed, it effectively ensures that even during maximum-intensity emergency braking, the maximum braking energy recharge power required by the vehicle will not exceed the battery's instantaneous receiving capacity under its current state. Thus, in a low-cost architecture without a traditional hydraulic braking system, it effectively eliminates the risk of braking force attenuation caused by high battery SOC or low temperatures, thereby providing stable, reliable, and predictable braking performance for the vehicle under all operating conditions, significantly improving the system's functional safety level and operational reliability.

[0040] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0041] Figure 1 This is a schematic flowchart of a vehicle braking control method provided as an exemplary embodiment of this application. The vehicle braking control method provided in this embodiment is applied to an electronic control unit in a vehicle, which also includes a drive motor and a power battery. Figure 1 As shown, the vehicle braking control method includes the following steps:

[0042] S101. During vehicle operation, obtain the current state of charge and current cell temperature of the power battery.

[0043] For example, during vehicle operation, electronic control units such as the Vehicle Control Unit (VCU) or Battery Management System (BMS) continuously or periodically collect real-time data reported by the power battery management module to obtain the current state of charge (SOC) value of the battery and the individual cell temperature value of representative cells.

[0044] S102. Based on a preset mapping relationship characterizing the maximum recharge power of the power battery under different states of charge and different cell temperatures, determine the maximum allowable recharge power corresponding to the current state of charge and current cell temperature.

[0045] In this step, the electronic control unit (e.g., the vehicle control unit, VCU) determines the maximum permissible recharge power based on the current state of charge (SOC) and current cell temperature of the power battery obtained in step S101. Specifically, the electronic control unit accesses a preset mapping relationship stored in its internal memory or the BMS it communicates with. This mapping relationship is established during the development phase through systematic calibration tests on a specific model of power battery configured for the vehicle. The testing process covers the entire expected operating range of the power battery, including but not limited to the continuous range of SOC from 0% to 100%, and the continuous range of cell temperature from its safe lower limit to its upper limit (e.g., -30°C to 60°C). Through this series of tests, the maximum recharge power that the battery model can safely withstand under each combination of SOC and cell temperature (usually a peak power lasting 2-3 seconds is used as the evaluation benchmark, referred to as 3-second recharge power) is obtained and recorded, thus forming the preset mapping relationship. This mapping relationship can be physically represented as a two-dimensional data table, a mathematical model stored in the controller, or a fitted function.

[0046] For example, Table 1 is an example of the mapping relationship of the maximum recharge power of a power battery under different states of charge and different cell temperatures provided by an exemplary embodiment of this application.

[0047] Table 1. Examples of mapping relationships between the maximum recharge power of power batteries under different states of charge and different single-cell temperatures.

[0048]

[0049] As shown in Table 1, when performing the above-mentioned determination operation, the electronic control unit uses the current state of charge (SOC) and the current cell temperature as input indices. If the precise combination of the current SOC and the current cell temperature exists on a data node with a preset mapping relationship, the corresponding maximum recharge power value is directly read. For example, the maximum recharge power value corresponding to a current cell temperature of -20°C and a current SOC of 10% is 3107W. If the precise combination of the current SOC and the current cell temperature is not directly located on a data node, for example, a current cell temperature of -15°C and a current SOC of 15%, the data of adjacent nodes are calculated using a preset interpolation algorithm (such as bilinear interpolation) to obtain the maximum allowable recharge power precisely corresponding to the current SOC and the current cell temperature. This maximum allowable recharge power value is the upper limit of the instantaneous electrical power that the drive motor is allowed to feed into the battery system during reverse braking at the current vehicle operating moment to ensure the safety of the power battery and reduce the risk of overcharging.

[0050] S103. Based on the pre-calibrated vehicle speed-power mapping relationship, determine the target limit vehicle speed corresponding to the maximum allowable recharge power. The vehicle speed-power mapping relationship is calibrated based on the external characteristics of the drive motor's reverse drag braking power supply and is used to define the maximum power supply that the drive motor can generate when performing maximum capacity reverse drag braking at different vehicle speeds.

[0051] In this step, the electronic control unit (ECU) performs the target speed limit determination operation based on the maximum permissible recharge power determined in step S102. Specifically, the ECU accesses a pre-calibrated speed-power mapping relationship stored internally. The process of establishing this mapping relationship is as follows: During the vehicle development phase, bench tests are conducted on the external power supply characteristics of the drive motor in reverse drag braking (i.e., power generation) mode. The tests measure and record the maximum DC power supply (i.e., maximum power generation) that the drive motor can stably output at different motor speeds (corresponding to different vehicle speeds). Through this series of tests, a data model is established that clearly characterizes the correspondence between "vehicle speed" and "the maximum power supply that the drive motor can generate when performing maximum reverse drag braking at that speed," namely the speed-power mapping relationship mentioned above. This relationship can also be represented as a one-dimensional data table or a fitted curve.

[0052] Accordingly, when performing the above-mentioned determination operation, the electronic control unit uses the maximum permissible recharge power output in step S102 as the query basis to find the highest vehicle speed corresponding to the current maximum permissible recharge power in the vehicle speed-power mapping relationship, where the defined "maximum power supply" is less than or equal to the current maximum permissible recharge power. A typical implementation is to perform a reverse query or iterative comparison on the mapping relationship to find the upper limit of vehicle speed that satisfies the condition that "when driving at this speed and below, even with maximum intensity reverse braking, the maximum power supply demand of the motor will not exceed the current maximum permissible recharge power of the battery." This finally determined upper limit of vehicle speed is the target speed limit.

[0053] S104. Control the vehicle to travel at a speed not exceeding the target speed limit.

[0054] For example, the electronic control unit uses the target speed limit as the maximum permissible speed boundary value for the vehicle's longitudinal movement and applies it to the vehicle's power control system. Based on this boundary value, the control system applies corresponding adjustments to the vehicle's drive or braking actuators, thus forming a closed-loop speed management mechanism. The core of this mechanism is that when the actual vehicle speed is detected to be approaching or exceeding the target speed limit, the control system adjusts the power output or applies resistance torque to generate a control action sufficient to suppress further speed increases or reduce the speed, dynamically maintaining the vehicle's actual speed within the range not exceeding the target speed limit. This process continues, ensuring that the target speed limit, as a rigid safety constraint, is effectively and in real-time during vehicle operation.

[0055] The vehicle braking control method provided in this application monitors the state of charge and cell temperature of the power battery in real time. Based on a preset battery state-maximum recharge power mapping relationship, it dynamically determines the maximum allowable recharge power of the power battery under the current operating conditions. Combined with a pre-calibrated vehicle speed-power mapping relationship, the power limit is accurately converted into the corresponding target speed limit. Ultimately, the vehicle is controlled to travel within the range not exceeding this speed limit. This effectively improves the safety hazards of braking force fluctuations and unstable braking effects caused by the limited energy recharge power due to high battery state of charge or low temperature when using motor reverse drag as the main braking scheme. Through the dynamic speed limiting strategy, it ensures from the source that the maximum braking power required by the vehicle never exceeds the real-time receiving capacity of the power battery. Thus, in a low-cost architecture without a traditional hydraulic braking system, it can effectively eliminate the risk of braking force attenuation caused by high battery state of charge or low temperature. In this way, it provides stable, reliable and predictable braking performance for the vehicle under all operating conditions, significantly improving the functional safety level and operational reliability of the system.

[0056] In some embodiments, the target speed limit corresponding to the maximum allowable recharge power is determined based on a pre-calibrated speed-power mapping relationship, including: querying the speed-power mapping relationship to obtain the maximum power supply value that is less than or equal to the maximum allowable recharge power; and determining the speed corresponding to the maximum power supply value as the target speed limit.

[0057] For example, Table 2 provides an example of the vehicle speed-power mapping relationship provided in an exemplary embodiment of this application.

[0058]

[0059] Accordingly, assuming that at a certain moment, after system calculation and evaluation, the maximum permissible recharge power is determined to be 2000W, the electronic control unit performs a lookup operation to determine the target speed limit. Specifically, using the maximum permissible recharge power of 2000W as the query threshold, the search begins in Table 2. For example, the maximum DC power of the power supply is compared row by row with the value of 2000W. When the comparison is made at a vehicle speed of 3km / h, the corresponding maximum DC power of the power supply is 2015W, which is greater than 2000W and does not meet the search criteria. However, at a vehicle speed of 2km / h, the corresponding maximum DC power of the power supply is 1040W, which is less than 2000W. This value is recorded and the search continues. It is found that there are no other maximum DC power values ​​less than or equal to 2000W. Among all maximum DC power values ​​less than or equal to 2000W, 1040W is the largest value, so it is used as the matching value. By querying the correspondence of this matching value (i.e., 1040W) in the data table, the unique vehicle speed value associated with it is determined to be 2km / h. Furthermore, this vehicle speed value of 2km / h is determined as the target speed limit.

[0060] In this embodiment of the application, the conversion from power constraints to vehicle speed constraints can be completed quickly and accurately through this simple comparison and retrieval logic, which helps to ensure the real-time response of the system and the stability and safety of the vehicle during the recharging process.

[0061] In some embodiments, controlling the vehicle to travel at a speed not exceeding a target speed limit includes: generating and outputting a speed limit command based on the target speed limit, so that the actual speed of the vehicle is controlled below the target speed limit.

[0062] For example, the electronic control unit generates a speed limit command containing target speed limit information. This command is sent to the actuator responsible for longitudinal motion control of the vehicle, which is typically the motor controller corresponding to the drive motor, or, in a more integrated architecture, the vehicle controller itself. Correspondingly, upon receiving the speed limit command, the actuator uses it as the maximum permissible speed setting for the vehicle at the current moment; subsequently, the actuator dynamically adjusts the output torque of the drive motor through closed-loop control logic (e.g., proportional-integral adjustment based on the difference between the current actual speed and the target speed limit). Its control objective is: when the vehicle's actual speed is lower than the target speed limit, normal driving is allowed; when the vehicle's actual speed reaches or is about to exceed the target speed limit, the actual speed is stably controlled within a range not exceeding the target speed limit by limiting the drive torque or actively applying anti-drag torque.

[0063] In some embodiments, before controlling the vehicle to travel at a speed not exceeding the target limit speed, the method further includes: determining, based on the external characteristics of the drive motor's anti-drag braking power supply, the vehicle's curb weight, and the transmission system efficiency, the theoretical braking distance of the vehicle from the target limit speed to a stop when performing maximum capacity anti-drag braking at the target limit speed; if the theoretical braking distance is greater than a preset safe braking distance threshold, iteratively reducing the target limit speed and re-determining the corresponding theoretical braking distance until the theoretical braking distance is not greater than the safe braking distance threshold; and using the speed that satisfies the requirement that the theoretical braking distance is not greater than the safe braking distance threshold as the target limit speed for control.

[0064] For example, assuming the vehicle's curb weight and transmission system efficiency are known, when the initially determined target speed limit is 8 km / h, the theoretical braking deceleration is calculated based on the external characteristics of the drive motor's anti-drag braking at 8 km / h (parameters such as maximum feed torque of 10.11 Nm), combined with the vehicle's curb weight and transmission system efficiency, using Newton's second law, and then the braking distance is calculated. To improve calculation accuracy, a segmented calculation method with speeds decreasing by 1 km / h can be used to accumulate the braking distances for each speed range in detail, obtaining a precise theoretical value.

[0065] Accordingly, assuming a preset safe braking distance threshold of 0.8m, this threshold is determined comprehensively based on relevant mandatory standards (such as GB21670), industry standards, or enterprise-developed safety specifications. If the calculated theoretical braking distance at 8km / h is 1.59m, which is greater than the safe braking distance threshold of 0.8m, then the target speed limit needs to be iteratively lowered. The target speed limit is lowered to 7km / h, and the corresponding theoretical braking distance is re-determined based on the external characteristics of the drive motor's anti-drag braking power supply at 7km / h, the vehicle's curb weight, and the transmission system efficiency. Referring again to the above-mentioned segmented braking distance calculation table, the relevant braking distance data corresponding to a speed of 7km / h can provide a reference for judgment. If the theoretical braking distance at 7km / h is still greater than the safe braking distance threshold, the target speed limit is further lowered, such as to 6km / h, and the above calculation and comparison process is repeated. Correspondingly, when the target speed limit is reduced to 5 km / h, the calculated theoretical braking distance is 0.59 m (based on a comprehensive judgment combining segmented calculation tables, etc.), which is not greater than the safe braking distance threshold of 0.8 m. Therefore, 5 km / h is used as the speed that satisfies the requirement that the theoretical braking distance is not greater than the safe braking distance threshold, and is thus used as the target speed limit for control.

[0066] This embodiment determines the theoretical braking distance based on the external characteristics of the drive motor's anti-drag braking power supply, the vehicle's curb weight, and the transmission system efficiency. This fully utilizes motor characteristics and vehicle parameters to accurately assess the vehicle's braking performance under maximum anti-drag braking at a specific target speed limit, making the braking distance calculation more scientific and targeted. When the theoretical braking distance exceeds a preset safe braking distance threshold, the target speed limit is iteratively lowered and the calculation is recalculated until the safety requirements are met. This process effectively ensures that the vehicle stops within a safe distance during braking, significantly reducing the risk of collisions and other safety accidents caused by excessive braking distances, and strongly guaranteeing vehicle driving safety. Simultaneously, using the speed that meets the conditions as the target speed limit for control provides a reliable basis for vehicle speed control, contributing to stable and safe vehicle operation.

[0067] In some embodiments, the preset mapping relationship characterizing the maximum recharge power of the power battery under different states of charge and different cell temperatures, and the pre-calibrated vehicle speed-power mapping relationship are based on the parameter calibration of the drive motor and the power battery that meet the system matching conditions. The system matching conditions include: the maximum DC power output of the drive motor under anti-drag braking conditions is less than the minimum continuous recharge power of the power battery in all states of charge and operating temperature ranges.

[0068] For example, the preset mapping relationship representing the maximum recharge power of the power battery at different states of charge (SOC) and different single-cell temperatures, as well as the pre-calibrated vehicle speed-power mapping relationship, are all strictly based on the parameter calibration of the drive motor and power battery to meet specific system matching conditions. The key condition for system matching is that the maximum DC power output of the drive motor under reverse braking conditions must be less than the minimum continuous recharge power of the power battery across all states of charge and operating temperature ranges. Specifically, in conjunction with the battery's maximum recharge power verification requirements, on the one hand, when the braking time does not exceed 2 seconds, an evaluation is conducted using a 3-second feedback mapping table (Characteristic Map, or MAP) to verify whether the selected battery can meet the maximum recharge power requirements at any SOC and single-cell temperature. For example, when the battery pack's SOC is below 99% and the individual battery cell temperature is greater than or equal to -10°C, the motor can provide full-power reverse braking. Similarly, when the battery pack's SOC is below 95% and the individual battery cell temperature is greater than or equal to -15°C, the motor can also provide full-power reverse braking. When the battery pack's SOC is below 60% and the individual battery cell temperature is greater than or equal to -20°C, the motor can also provide full-power reverse braking, but at -20°C, the battery pack has no feedback capability at full SOC, requiring a clearly defined heating threshold. On the other hand, to ensure safe battery use and reduce overcharging, the design principles explicitly stipulate that the maximum DC power supplied by the motor must be less than the battery's 3-second recovery power. Accordingly, under these verification principles and battery characteristic constraints, the above mapping relationship was determined through precise calibration of the drive motor and power battery parameters. This ensures that during vehicle operation, the drive motor and power battery achieve efficient and safe collaborative operation, providing stable and reliable energy feedback and continuous strong power support for the vehicle.

[0069] Based on the above embodiments, in some embodiments, the vehicle further includes an electromagnetic brake, and the vehicle braking control method further includes an emergency braking step: when the reverse drag braking function of the drive motor is detected to be ineffective and the current vehicle speed is lower than a preset emergency braking activation speed threshold, the electromagnetic brake is triggered to perform emergency braking.

[0070] For example, Table 3 provides an example of the maximum permissible driving speed at high SOC and low temperature conditions provided by an exemplary embodiment of this application.

[0071]

[0072] For example, in addition to conventional braking components and drive motors, the vehicle also includes an electromagnetic brake. Its braking control method adds an emergency braking step to the conventional braking process. Specifically, during vehicle operation, the anti-drag braking function of the drive motor is monitored in real time. Simultaneously, a preset emergency braking activation speed threshold is established, which considers factors such as the vehicle's overall braking performance requirements and safety standards. Based on Table 3 showing the maximum permissible driving speeds at high SOC and low temperatures, the battery exhibits different 3s recharge power at different SOCs and individual cell temperatures, corresponding to different maximum permissible driving speeds. Furthermore, the electromagnetic brake is explicitly considered as an emergency braking mechanism: for example, when the 3s recharge power is less than 300W and the maximum permissible driving speed is less than 1km / h (this is a pending value to be determined based on actual conditions), the electromagnetic brake is used for emergency braking. When the reverse braking function of the drive motor is detected to have failed, and the current vehicle speed is detected by the vehicle speed sensor and other devices to be lower than the preset emergency braking activation speed threshold, such as 1 km / h, the vehicle's electronic control unit will immediately trigger the electromagnetic brake to perform emergency braking, so as to ensure that the vehicle can stop quickly within a safe distance, protect driving safety, and reduce safety accidents caused by reverse braking failure and ineffective speed control.

[0073] In this embodiment, an emergency braking activation speed threshold is preset, and when the anti-drag braking function is detected to have failed and the current vehicle speed is below the threshold, an electromagnetic brake is triggered to perform emergency braking, adding a reliable layer of protection to the vehicle braking system. Moreover, the electromagnetic brake responds quickly and can generate strong braking force in a short time, enabling the vehicle to decelerate and stop rapidly, effectively reducing safety accidents such as collisions and running off the road caused by brake failure, and significantly improving the safety and reliability of vehicle driving.

[0074] In some embodiments, triggering the electromagnetic brake for emergency braking includes: determining the upper limit of the number of emergency braking triggers allowed per unit time or unit mileage based on the vehicle's total design life or total mileage and the electromagnetic brake's calibrated emergency braking usage life; and triggering the electromagnetic brake for emergency braking when the actual number of emergency braking triggers in the current cycle does not exceed the upper limit.

[0075] The electromagnetic brake has a clearly defined lifespan for emergency braking at different speeds. For example, assuming a speed of 0 r / min corresponds to a vehicle speed of 0 km / h, the electromagnetic brake can maintain braking for 1 million times; at a speed of 363 r / min corresponding to a vehicle speed of 1 km / h, the electromagnetic brake can be used for emergency braking 500,000 times. During the process of triggering the electromagnetic brake for emergency braking, multiple factors are considered. These include the vehicle's designed total lifespan or total mileage (e.g., 10 years or 200,000 km), and the electromagnetic brake's calibrated lifespan for emergency braking. Based on these data, the upper limit of the permissible number of emergency braking triggers per unit time (e.g., year, month) or unit mileage (e.g., every 10,000 km) is further determined.

[0076] During actual vehicle operation, the number of emergency braking triggers within the current cycle is counted in real time. When the number of emergency braking triggers within the current cycle does not exceed the predetermined upper limit, the electromagnetic brake is activated for emergency braking to ensure safe braking while using the electromagnetic brake appropriately and extending its service life. Conversely, when the number of emergency braking triggers within the current cycle exceeds the predetermined upper limit, a series of warning and restriction measures will be initiated. For example, an emergency alert will be sent to the driver through the vehicle's instrument panel display and audible alarms to remind the driver that emergency braking is being used too frequently and that caution should be exercised to minimize unnecessary emergency braking operations. At the same time, the vehicle's driving status will be more strictly monitored, and without affecting the vehicle's basic driving functions, some driving modes or functions that may trigger frequent emergency braking will be appropriately restricted, such as limiting the vehicle's maximum speed and disabling certain aggressive driving assistance modes, to reduce the probability of emergency braking triggers, protect the electromagnetic brake, and ensure that the vehicle can continue to operate safely and stably.

[0077] This application embodiment determines the upper limit of emergency braking trigger times by combining the vehicle's total design life or total mileage with the electromagnetic brake's rated lifespan. This allows for reasonable planning of electromagnetic brake usage, reducing premature damage caused by excessive and frequent emergency braking, effectively extending the electromagnetic brake's lifespan, and lowering vehicle maintenance costs. Furthermore, by only executing emergency braking when the actual number of triggers within the current cycle does not exceed the upper limit, the use of the electromagnetic brake is effectively controlled while ensuring timely braking in emergency situations and guaranteeing driving safety. This achieves a balance between vehicle safety performance and component lifespan, contributing to improved overall vehicle operational stability and cost-effectiveness.

[0078] In summary, this application has at least the following advantages:

[0079] 1. By monitoring the state of charge (SOC) and individual cell temperature of the power battery in real time, and based on a preset battery SOC-maximum recharge power mapping relationship, the maximum allowable recharge power of the power battery under the current operating conditions is dynamically determined. Combined with a pre-calibrated vehicle speed-power mapping relationship, the power limit is accurately converted into the corresponding target speed limit, ultimately controlling the vehicle to travel within the range not exceeding this speed. This effectively improves the safety hazards of braking force fluctuations and unstable braking effects caused by the limited energy recharge power due to high battery SOC or low temperature when using motor reverse drag as the main braking scheme. Through the dynamic speed limiting strategy, the maximum braking power required by the vehicle is ensured from the source to always exceed the real-time receiving capacity of the power battery. Thus, in a low-cost architecture without a traditional hydraulic braking system, the risk of braking force attenuation caused by high battery SOC or low temperature can be effectively eliminated. This provides stable, reliable, and predictable braking performance for the vehicle under all operating conditions, significantly improving the functional safety level and operational reliability of the system.

[0080] Second, by determining the theoretical braking distance based on the external characteristics of the drive motor's reverse braking power supply, the vehicle's curb weight, and the efficiency of the transmission system, the system can fully utilize the motor's characteristics and the vehicle's own parameters to accurately evaluate the vehicle's braking performance under maximum reverse braking capacity at a specific target speed limit. This makes the braking distance calculation more scientific and targeted. When the theoretical braking distance exceeds the preset safe braking distance threshold, the target speed limit is iteratively lowered and the calculation is recalculated until the safety requirements are met. This process effectively ensures that the vehicle can stop within a safe distance during braking, significantly reducing the risk of collisions and other safety accidents caused by excessive braking distances, and strongly guaranteeing vehicle driving safety. At the same time, using the speed that meets the conditions as the target speed limit for control provides a reliable basis for vehicle speed control, contributing to the stable and safe operation of the vehicle.

[0081] Third, by setting a preset emergency braking activation speed threshold, and triggering the electromagnetic brake for emergency braking when the reverse drag braking function fails and the current vehicle speed is below the threshold, a reliable safeguard is added to the vehicle braking system; moreover, the electromagnetic brake responds quickly and can generate strong braking force in a short time, enabling the vehicle to decelerate and stop quickly, effectively reducing safety accidents such as collisions and running off the road caused by brake failure, and significantly improving the safety and reliability of vehicle driving.

[0082] The following are embodiments of the apparatus described in this application, which can be used to execute the embodiments of the method described in this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the method described in this application.

[0083] Figure 2This is a schematic diagram of a vehicle braking control device provided as an exemplary embodiment of this application. The vehicle braking control device provided in this embodiment is applied to an electronic control unit in a vehicle, which also includes a drive motor and a power battery. Figure 2 As shown, the vehicle braking control device 20 includes an acquisition module 21, a first determination module 22, a second determination module 23, and a control module 24, wherein:

[0084] The acquisition module 21 is used to acquire the current state of charge and current cell temperature of the power battery during vehicle operation.

[0085] The first determining module 22 is used to determine the maximum allowable recharge power corresponding to the current state of charge and the current cell temperature based on a preset mapping relationship that characterizes the maximum recharge power of the power battery under different states of charge and different cell temperatures.

[0086] The second determining module 23 is used to determine the target limiting vehicle speed corresponding to the maximum allowable recharge power based on the pre-calibrated vehicle speed-power mapping relationship. The vehicle speed-power mapping relationship is calibrated based on the external characteristics of the reverse drag braking power supply of the drive motor and is used to define the maximum power supply that the drive motor can generate when performing maximum capacity reverse drag braking at different vehicle speeds.

[0087] The control module 24 is used to control the vehicle to travel at a speed not exceeding the target speed limit.

[0088] In one possible implementation, the second determining module 23 may be specifically used to: query the vehicle speed-power mapping relationship, obtain the maximum power supply value that is less than or equal to the maximum allowable recharge power; and determine the vehicle speed corresponding to the maximum power supply value as the target speed limit.

[0089] In one possible implementation, the control module 24 may be specifically used to: generate and output a speed limit command based on the target speed limit, so that the actual speed of the vehicle is controlled below the target speed limit.

[0090] In one possible implementation, before controlling the vehicle to travel at a speed not exceeding the target limit, the control module 24 can also be used to: determine the theoretical braking distance from the target limit speed to a stop when performing maximum capacity reverse braking at the target limit speed, based on the external characteristics of the drive motor's reverse braking power supply, the vehicle's curb weight, and the transmission system efficiency; if the theoretical braking distance is greater than a preset safe braking distance threshold, iteratively reduce the target limit speed and re-determine the corresponding theoretical braking distance until the theoretical braking distance is not greater than the safe braking distance threshold; and use the speed that satisfies the requirement that the theoretical braking distance is not greater than the safe braking distance threshold as the target limit speed for control.

[0091] In one possible implementation, the preset mapping relationship characterizing the maximum recharge power of the power battery under different states of charge and different cell temperatures, and the pre-calibrated vehicle speed-power mapping relationship are based on the parameter calibration of the drive motor and the power battery that meet the system matching conditions. The system matching conditions include: the maximum DC power output of the drive motor under reverse drag braking conditions is less than the minimum continuous recharge power of the power battery in all states of charge and operating temperature ranges.

[0092] In one possible implementation, the vehicle also includes an electromagnetic brake, and the control module 24 can also be used to: trigger the electromagnetic brake to perform emergency braking when the anti-drag braking function of the drive motor is detected to be ineffective and the current vehicle speed is lower than a preset emergency braking activation speed threshold.

[0093] In one possible implementation, the control module 24 can also be used to: determine the upper limit of the number of emergency braking triggers allowed per unit time or unit mileage based on the vehicle's total design life or total mileage and the calibrated emergency braking usage life of the electromagnetic brake; and when the actual number of emergency braking triggers in the current cycle does not exceed the upper limit, execute the triggering of the electromagnetic brake to perform emergency braking.

[0094] The vehicle braking control device provided in this application embodiment can execute the technical solution shown in the above vehicle braking control method embodiment. Its implementation principle and beneficial effects are similar, and will not be described again here.

[0095] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0096] It should be further noted that although the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0097] It should be noted that the above-described device embodiments are merely illustrative, and the device of this application can also be implemented in other ways; and it should be understood that the division of the various modules of the above device is only a logical functional division, and in actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, these modules can all be implemented in software through processing element calls; they can all be implemented in hardware; or some modules can be implemented in software through processing element calls, and some modules can be implemented in hardware. For example, the control module can be a separately established processing element, or it can be integrated into a chip of the above device. Alternatively, it can be stored as program code in the memory of the above device, and its functions can be called and executed by a processing element of the above device. The implementation of other modules is similar. In addition, these modules can be fully or partially integrated together, or they can be implemented independently. The processing element here can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above modules can be completed through hardware integrated logic circuits in the processor element or software instructions.

[0098] For example, these modules can be one or more integrated circuits configured to implement the above methods, such as one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs). As another example, when a module is implemented using processing element scheduler code, the processing element can be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of calling program code. Furthermore, these modules can be integrated together as a System-On-a-Chip (SOC).

[0099] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., Digital Video Discs, DVDs), or semiconductor media (e.g., solid-state disks (SSDs)).

[0100] Figure 3 A schematic diagram of the structure of an electronic control unit provided for an exemplary embodiment of this application. (See attached diagram.) Figure 3 As shown, the electronic control unit 30 in this embodiment includes:

[0101] At least one processor 31; and a memory 32 communicatively connected to at least one processor;

[0102] The memory 32 stores instructions that can be executed by at least one processor 31 to cause the electronic control unit to perform the method as described in any of the above embodiments.

[0103] Alternatively, the memory 32 can be either standalone or integrated with the processor 31.

[0104] The memory 32 may include high-speed random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage device.

[0105] The processor 31 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application. Specifically, when implementing the vehicle braking control method described in the foregoing method embodiments, the electronic control unit may be, for example, an electronic device with processing capabilities such as a server.

[0106] Optionally, the electronic control unit may also include a communication interface 33. In specific implementations, if the communication interface 33, memory 32, and processor 31 are implemented independently, they can be interconnected via a bus to complete communication. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc., but this does not imply that there is only one bus or one type of bus.

[0107] Optionally, in a specific implementation, if the communication interface 33, memory 32 and processor 31 are integrated on a single chip, then the communication interface 33, memory 32 and processor 31 can communicate through an internal interface.

[0108] The implementation principle and technical effects of the electronic control unit provided in this embodiment can be found in the foregoing embodiments, and will not be repeated here.

[0109] This application also provides a vehicle including the electronic control unit as described in the above embodiments.

[0110] This application also provides a computer-readable storage medium storing computer-executable instructions. When the computer-executable instructions are executed, they are used to implement the method steps as described in the above method embodiments. The specific implementation methods and technical effects are similar and will not be repeated here.

[0111] The aforementioned computer-readable storage media can be implemented from any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Read Only Memory (PROM), Read Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0112] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an application-specific integrated circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in a vehicle braking control device.

[0113] This application also provides a computer program product, including a computer program, which, when executed, implements the method steps as described in the above method embodiments. The specific implementation and technical effects are similar and will not be repeated here.

[0114] In the above embodiments, the descriptions of each embodiment have their own emphasis. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0115] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0116] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A vehicle braking control method, characterized in that, An electronic control unit applied in the vehicle, the vehicle further comprising a drive motor and a power battery, the method comprising: During the vehicle's operation, the current state of charge and current individual cell temperature of the power battery are acquired. Based on a preset mapping relationship characterizing the maximum recharge power of the power battery under different states of charge and different cell temperatures, the maximum allowable recharge power corresponding to the current state of charge and the current cell temperature is determined. Based on the pre-calibrated vehicle speed-power mapping relationship, the target limiting vehicle speed corresponding to the maximum allowable recharge power is determined. The vehicle speed-power mapping relationship is calibrated based on the external characteristics of the reverse drag braking power supply of the drive motor, and is used to define the maximum power supply that the drive motor can generate when performing maximum reverse drag braking at different vehicle speeds. Based on the reverse drag braking power supply characteristics of the drive motor, the vehicle's curb weight, and the transmission system efficiency, the theoretical braking distance of the vehicle from the target limit speed to a stop when performing maximum capacity reverse drag braking at the target limit speed is determined. If the theoretical braking distance is greater than the preset safe braking distance threshold, the target speed limit is iteratively reduced, and the corresponding theoretical braking distance is re-determined until the theoretical braking distance is not greater than the safe braking distance threshold. The vehicle speed that satisfies the theoretical braking distance not being greater than the safe braking distance threshold is used as the target speed limit for control. Control the vehicle to travel at a speed not exceeding the target speed limit.

2. The vehicle braking control method according to claim 1, characterized in that, The determination of the target speed limit corresponding to the maximum permissible recharge power based on the pre-calibrated vehicle speed-power mapping relationship includes: Query the vehicle speed-power mapping relationship to obtain the maximum power supply value that is less than or equal to the maximum allowable recharge power; The vehicle speed corresponding to the maximum power supply value is determined as the target speed limit.

3. The vehicle braking control method according to claim 2, characterized in that, Controlling the vehicle to travel at a speed not exceeding the target speed limit includes: Based on the target speed limit, a speed limit command is generated and output so that the actual speed of the vehicle is controlled below the target speed limit.

4. The vehicle braking control method according to any one of claims 1 to 3, characterized in that, The preset mapping relationship characterizing the maximum recharge power of the power battery under different states of charge and different individual cell temperatures, and the pre-calibrated vehicle speed-power mapping relationship, are based on the parameter calibration of the drive motor and the power battery that meet the system matching conditions. The system matching conditions include: the maximum DC power output of the drive motor under anti-drag braking conditions is less than the minimum continuous recharge power of the power battery under all states of charge and within the allowable recharge operating temperature range.

5. The vehicle braking control method according to any one of claims 1 to 3, characterized in that, The vehicle also includes an electromagnetic brake, and the method further includes an emergency braking step: When the reverse drag braking function of the drive motor is detected to be ineffective and the current vehicle speed is lower than the preset emergency braking activation speed threshold, the electromagnetic brake is triggered to perform emergency braking.

6. The vehicle braking control method according to claim 5, characterized in that, The process of triggering the electromagnetic brake to perform emergency braking includes: Based on the total design life or total mileage of the vehicle and the calibrated emergency braking usage life of the electromagnetic brake, determine the upper limit of the number of emergency braking triggers allowed per unit time or unit mileage. If the actual number of emergency braking triggers in the current cycle does not exceed the upper limit, the electromagnetic brake is triggered to perform emergency braking.

7. A vehicle braking control device, characterized in that, An electronic control unit applied in the vehicle, the vehicle further comprising a drive motor and a power battery, the device comprising: The acquisition module is used to acquire the current state of charge and current cell temperature of the power battery during the vehicle's operation. The first determining module is used to determine the maximum allowable recharge power corresponding to the current state of charge and the current cell temperature based on a preset mapping relationship that characterizes the maximum recharge power of the power battery under different states of charge and different cell temperatures. The second determining module is used to determine the target limiting vehicle speed corresponding to the maximum allowable recharge power based on a pre-calibrated vehicle speed-power mapping relationship, wherein the vehicle speed-power mapping relationship is calibrated based on the external characteristics of the reverse drag braking power supply of the drive motor, and is used to define the maximum power supply that the drive motor can generate when performing maximum capacity reverse drag braking at different vehicle speeds. The control module is used to determine, based on the reverse drag braking power supply characteristics of the drive motor, the vehicle's curb weight, and the transmission system efficiency, the theoretical braking distance of the vehicle from the target limited speed to a stop when performing maximum reverse drag braking at the target limited speed; if the theoretical braking distance is greater than a preset safe braking distance threshold, the target limited speed is iteratively reduced, and the corresponding theoretical braking distance is re-determined until the theoretical braking distance is not greater than the safe braking distance threshold; the speed at which the theoretical braking distance is not greater than the safe braking distance threshold is used as the target limited speed for control; and the vehicle is controlled to travel at a speed not exceeding the target limited speed.

8. An electronic control unit, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory is used to store computer-executed instructions; The processor is configured to execute the computer execution instructions to implement the method as described in any one of claims 1 to 6.

9. A vehicle, characterized in that, Includes the electronic control unit as described in claim 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed, are used to implement the method as described in any one of claims 1 to 6.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed, it implements the method as described in any one of claims 1 to 6.

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