Braking torque control method and vehicle

Abstract

A braking torque control method and a vehicle, which belong to the technical field of vehicle torque control. When it is determined that braking torque compensation needs to be performed, the maximum value of a braking torque can be limited by means of a maximum available torque, thereby preventing wheel lockup caused by the braking control process and avoiding driving hazards. When a braking compensation condition is satisfied, it indicates that required electric braking cannot independently complete the braking control, and a braking system needs to participate in braking compensation. When braking compensation is performed, required braking torques need to be allocated to different drive axles on the basis of a drive mode, and load conditions of the different drive axles are determined by determining limit-exceeding torques of the different drive axles, thereby preventing wheel lockup of the drive axles during the braking compensation control process, and ensuring the safety of the braking compensation process. Thus, wheel lockup caused by braking compensation is prevented while braking compensation is implemented, and the safety of the braking compensation process is ensured while the deceleration effect is ensured.

Description

Braking torque control methods and vehicles

[0001] This application claims priority to Chinese Patent Application No. 202510384171.7, filed on March 28, 2025, entitled "Method for Controlling Braking Torque and Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of vehicle torque control technology, and in particular to a method for controlling braking torque and a vehicle. Background Technology

[0003] When a vehicle brakes, there are multiple sources of braking torque. Generally, electric braking is used first for braking control. This is especially true in scenarios where the driver needs to coast from medium to high speeds without pressing the brake pedal to enter the speed control range activated by the crawl function, or in low-speed crawling scenarios. In these situations, the electric motor needs to output braking torque. However, due to the inherent characteristics of the electric motor and the charging power of the battery, the braking torque output by electric braking has an upper limit. This can lead to insufficient braking force in some driving scenarios, preventing the vehicle from achieving the set speed control and creating safety risks. Summary of the Invention

[0004] In view of this, the purpose of this disclosure is to propose a method for controlling braking torque and a vehicle that improves braking control performance while ensuring vehicle driving safety.

[0005] To achieve the above objectives, this disclosure provides a method for controlling braking torque, comprising:

[0006] The torque difference between the total demand torque and the maximum motor recovery torque satisfies the compensation state condition. The maximum available torque is determined based on the front axle anti-lock torque and the rear axle anti-lock torque. The braking compensation condition is then determined based on the maximum motor recovery torque and the maximum available torque.

[0007] In response to meeting the braking compensation conditions, the front axle distribution torque and the rear axle distribution torque are determined based on the drive mode and the maximum motor regenerative torque.

[0008] The over-limit torque of the front axle is determined based on the front axle distribution torque and the front axle anti-lock torque, and the over-limit torque of the rear axle is determined based on the rear axle distribution torque and the rear axle anti-lock torque.

[0009] Braking compensation control is performed based on the drive mode, rear axle over-limit torque, and front axle over-limit torque.

[0010] Optionally, brake compensation control is performed based on the drive mode, rear axle over-limit torque, and front axle over-limit torque, including:

[0011] In response to the drive mode being four-wheel drive, the hydraulic compensation torque requirement is determined based on the maximum available torque and the total regenerative torque requirement.

[0012] Determine the first torque compensation state for the front axle over-limit torque and the second torque compensation state for the rear axle over-limit torque;

[0013] In response to both the first torque compensation state and the second torque compensation state being in a torque surplus state, braking compensation control is performed based on the hydraulic compensation demand torque, the rear axle over-limit torque, and the front axle over-limit torque.

[0014] In response to the difference between the first torque compensation state and the second torque compensation state, torque transfer control is performed based on the over-limit torque of the rear axle and the over-limit torque of the front axle to obtain the torque transfer result, and braking compensation control is performed based on the torque transfer result and the hydraulic compensation torque requirement.

[0015] Optionally, brake compensation control is performed based on the hydraulic compensation torque requirement, the rear axle over-limit torque, and the front axle over-limit torque, including:

[0016] The sum of the over-limit torque of the rear axle and the over-limit torque of the front axle is determined as the available compensation torque;

[0017] In response to the available compensation torque being less than or equal to the hydraulic compensation demand torque, the rear axle over-limit torque is determined as the rear axle hydraulic compensation torque, and the front axle over-limit torque is determined as the front axle hydraulic compensation torque.

[0018] In response to the fact that the available compensation torque is greater than the hydraulic compensation required torque, the hydraulic compensation required torque is allocated and compensated according to the ratio of the over-limit torque of the rear axle to the over-limit torque of the front axle.

[0019] Optionally, torque transfer control is performed based on the over-limit torque of the rear axle and the over-limit torque of the front axle to obtain torque transfer results, including:

[0020] In response to the first torque compensation state being an over-limit state and the second torque compensation state being a remaining state, the anti-lock braking torque of the front axle is determined as the torque requested by the front axle motor, the absolute value of the over-limit torque of the front axle is transferred to the rear drive axle, and the sum of the absolute values ​​of the rear axle distributed torque and the over-limit torque of the front axle is determined as the torque requested by the rear axle motor, thus obtaining the first torque transfer result.

[0021] In response to the first torque compensation state being a residual state and the second torque compensation state being an over-limit state, the rear axle anti-lock torque is determined as the rear axle motor requested torque, the absolute value of the rear axle over-limit torque is transferred to the front drive axle, and the sum of the absolute values ​​of the front axle distributed torque and the rear axle over-limit torque is determined as the front axle motor requested torque, thus obtaining the second torque transfer result.

[0022] Optionally, braking compensation control is performed based on the torque transfer result and the hydraulic compensation required torque, including:

[0023] The sum of the over-limit torque of the front axle and the over-limit torque of the rear axle is determined as the available remaining torque;

[0024] In response to the torque transfer result being the first torque transfer result, and the available remaining torque being less than or equal to the hydraulic compensation demand torque, the available remaining torque is determined as the first hydraulic request torque to be compensated to the rear axle;

[0025] In response to the torque transfer result being the first torque transfer result, and the available remaining torque being greater than the hydraulic compensation demand torque, the hydraulic compensation demand torque is determined as the first hydraulic request torque to be compensated to the rear axle;

[0026] In response to the torque transfer result being the second torque transfer result, and the available remaining torque being less than or equal to the hydraulic compensation demand torque, the available remaining torque is determined as the second hydraulic request torque to be compensated to the front axle;

[0027] In response to the torque transfer result being the second torque transfer result, and the available remaining torque being greater than the hydraulic compensation demand torque, the hydraulic compensation demand torque is determined as the second hydraulic request torque to be compensated to the front axle.

[0028] Optionally, the hydraulic compensation required torque is determined based on the maximum available torque and the total recovery torque demand, including:

[0029] In response to the maximum available torque being greater than or equal to the total recovery demand torque, the difference between the total recovery demand torque and the maximum motor recovery torque is determined as the hydraulic compensation demand torque.

[0030] In response to the maximum available torque being less than the total required recovery torque, the difference between the maximum available torque and the maximum motor recovery torque is determined as the hydraulic compensation required torque.

[0031] Optionally, the determination of whether the compensation state condition is met is based on the difference between the maximum motor recovery torque and the total recovery demand torque, including:

[0032] In response to the differential torque being greater than or equal to a preset first torque threshold, it is determined that the compensation state condition is met.

[0033] In response to the differential torque being less than a preset second torque threshold, it is determined that the compensation state condition is not met;

[0034] Among them, the first torque threshold is greater than the second torque threshold.

[0035] Optionally, the determination of whether the compensation state condition is met is based on the difference between the maximum motor recovery torque and the total recovery demand torque, including:

[0036] In response to a differential torque being less than a preset first torque threshold and greater than or equal to a preset second torque threshold, the historical change type of the differential torque is determined;

[0037] If the historical change type changes from less than the second torque threshold to greater than or equal to the second torque threshold, it is determined that the compensation state condition is not met.

[0038] In response to a historical change type that changes from being greater than or equal to a first torque threshold to being less than a first torque threshold, it is determined that the compensation state condition is met.

[0039] Optionally, the maximum motor recovery torque is the minimum of the equivalent torque corresponding to the maximum battery recovery power and the equivalent torque corresponding to the maximum motor power generation.

[0040] Optionally, whether the braking compensation conditions are met is determined based on the maximum motor regenerative torque and the maximum available torque, including:

[0041] If the maximum available torque is less than or equal to the maximum motor recovery torque, it is determined that the braking compensation condition is not met.

[0042] The braking compensation condition is determined to be met when the maximum available torque is greater than the maximum motor recovery torque.

[0043] Optionally, brake compensation control based on drive mode, rear axle over-limit torque, and front axle over-limit torque also includes:

[0044] In response to the dual-drive mode, the active drive axle and the driven drive axle are determined in the front drive axle and the rear drive axle. The target over-limit torque of the active drive axle is determined in the over-limit torque of the rear axle and the over-limit torque of the front axle, and the target torque compensation state of the target over-limit torque is determined.

[0045] In response to the target torque compensation state being in an over-limit state, torque compensation control is performed on the driven axle based on the target anti-lock torque and total recovery torque demand of the active drive axle.

[0046] In response to the target torque compensation state being in the residual state, torque compensation control is performed on the driven drive axle and / or the active drive axle based on the total required torque and the maximum motor recovery torque.

[0047] Optionally, torque compensation control is performed on the driven axle based on the target anti-lock torque and total regenerative braking torque required by the active drive axle, including:

[0048] The difference between the total required recovery torque and the anti-lock braking torque of the active drive axle is determined as the dual-drive braking compensation torque.

[0049] In response to the fact that the dual-drive braking compensation torque is greater than the driven drive axle anti-lock torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque.

[0050] In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0051] Optionally, torque compensation control is performed on the driven drive axle and / or the driving drive axle based on the total reclaimed torque and the maximum motor reclaimed torque, including:

[0052] The difference between the total required recovery torque and the maximum motor recovery torque is determined as the dual-drive braking compensation torque.

[0053] In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0054] In response to the dual-drive braking compensation torque being greater than the driven drive axle anti-lock torque and less than or equal to the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the difference between the dual-drive braking compensation torque and the driven drive axle anti-lock torque is determined as the active hydraulic compensation torque.

[0055] In response to the fact that the dual-drive braking compensation torque is greater than the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the target over-limit torque is determined as the active hydraulic compensation torque.

[0056] Optionally, torque compensation control is performed on the driven axle based on the target anti-lock torque and total regenerative braking torque required by the active drive axle, including:

[0057] The difference between the total required recovery torque and the anti-lock braking torque of the active drive axle is determined as the dual-drive braking compensation torque.

[0058] In response to the fact that the dual-drive braking compensation torque is greater than the driven drive axle anti-lock torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque.

[0059] In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0060] Optionally, torque compensation control is performed on the driven drive axle and / or the driving drive axle based on the total reclaimed torque and the maximum motor reclaimed torque, including:

[0061] The difference between the total required recovery torque and the maximum motor recovery torque is determined as the dual-drive braking compensation torque.

[0062] In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0063] In response to the dual-drive braking compensation torque being greater than the driven drive axle anti-lock torque and less than or equal to the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the difference between the dual-drive braking compensation torque and the driven drive axle anti-lock torque is determined as the active hydraulic compensation torque.

[0064] In response to the fact that the dual-drive braking compensation torque is greater than the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the target over-limit torque is determined as the active hydraulic compensation torque.

[0065] Optionally, the method for controlling braking torque also includes:

[0066] In response to the failure to meet the braking compensation conditions, the front axle anti-lock braking torque is determined as the torque requested by the front axle motor, and the rear axle anti-lock braking torque is determined as the torque requested by the rear axle motor.

[0067] Based on the same inventive concept, this disclosure also provides a vehicle including an electronic device, the electronic device including a memory, a processor and a computer program stored in the memory and executable by the processor, the processor implementing the above method when executing the computer program.

[0068] As can be seen from the above, the braking torque control method and vehicle provided in this disclosure, when the difference between the total required recovery torque and the maximum motor recovery torque meets the compensation condition, determine the maximum available torque based on the front axle anti-lock braking torque and the rear axle anti-lock braking torque, and determine whether the braking compensation condition is met based on the maximum motor recovery torque and the maximum available torque; when the braking compensation condition is met, determine the front axle distribution torque and the rear axle distribution torque based on the drive mode and the maximum motor recovery torque; determine the front axle over-limit torque based on the front axle distribution torque and the front axle anti-lock braking torque, and determine the rear axle over-limit torque based on the rear axle distribution torque and the rear axle anti-lock braking torque; and perform braking compensation control based on the drive mode, the rear axle over-limit torque, and the front axle over-limit torque. When it is determined that braking torque compensation is required, the maximum value of the braking torque is limited by the maximum available torque to avoid wheel lock-up during the braking control process and to avoid driving hazards. Meeting the braking compensation conditions indicates that electric braking cannot complete braking control alone and the braking system needs to participate in braking compensation. During braking compensation, the required braking torque needs to be distributed to different drive axles according to the driving mode. The load conditions of different drive axles are determined by determining the over-limit torque of different drive axles to avoid wheel lock-up during the braking compensation control process, thus ensuring the safety of the braking compensation process. This achieves braking compensation while avoiding wheel lock-up caused by braking compensation, ensuring both deceleration effect and safety of the braking compensation process. Attached Figure Description

[0069] To more clearly illustrate the technical solutions in this disclosure or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0070] Figure 1 is a flowchart of the braking torque control method according to an embodiment of the present disclosure;

[0071] Figure 2 is a flowchart of brake compensation control in four-wheel drive mode according to an embodiment of this disclosure;

[0072] Figure 3 is a flowchart of torque transfer control according to an embodiment of this disclosure;

[0073] Figure 4 is a flowchart of braking compensation control after torque conversion according to an embodiment of this disclosure;

[0074] Figure 5 is a flowchart of an embodiment of the present disclosure for determining whether the braking compensation conditions are met;

[0075] Figure 6 is a flowchart of brake compensation control in dual-drive mode according to an embodiment of this disclosure;

[0076] Figure 7 is a schematic diagram of the braking torque control device according to an embodiment of the present disclosure;

[0077] Figure 8 is a schematic diagram of the structure of an electronic device according to an embodiment of this disclosure. Detailed Implementation

[0078] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0079] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in the embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0080] In this article, it is important to understand that any number of elements in the accompanying figures is for illustrative purposes and not for limitation, and any naming is for distinction only and has no limiting meaning.

[0081] Based on the above background description, the following situations also exist in the related technologies:

[0082] In related technologies, the motor system of new energy vehicles has two states: driving state and regeneration state. In the driving state, the driving torque can be released to accelerate the vehicle (corresponding to the battery discharge state). In the regeneration state, it is similar to the chassis braking system to decelerate the vehicle while charging the battery. In other words, under certain circumstances, the regeneration state of the motor can be used to decelerate the vehicle and charge the battery at the same time, thereby improving the driving range.

[0083] Based on the characteristic that the motor of a new energy vehicle can simultaneously have both driving and regeneration states, the vehicle control unit (VCU) has added a low-speed crawl function. For vehicles with a crawl mode, after entering crawl mode, PI closed-loop control (Proportional Integral control) is performed based on the speed difference between the target speed and the actual speed, so that the vehicle eventually reaches and stabilizes at the target speed. However, on roads with slopes, there is a risk of rolling back after entering crawl mode.

[0084] The specific control logic of the low-speed creep function in the VCU is as follows: First, a target vehicle speed is set. Then, based on the actual vehicle speed sent by the Anti-lock Braking System (ABS), PI control is performed using the speed difference between the target and actual vehicle speeds to allow the vehicle to eventually reach and stabilize at the target speed. That is, when the actual vehicle speed > the target vehicle speed, the creep torque is reduced to control vehicle deceleration; when the actual vehicle speed < the target vehicle speed, the creep torque is increased to control vehicle acceleration. This is roughly divided into two types: starting creep (allowing the vehicle to start from a standstill or low speed without pressing the accelerator) and coasting creep (allowing the vehicle to decelerate from a medium-high speed to a low-speed creep state without pressing the brake). The low-speed creep function is only available in D and R gears.

[0085] When a driver moves from a medium to high speed without applying the brake pedal and needs to coast into the speed control range activated by the creep function, especially after the creep function is activated, there may be creep driving scenarios such as reverse (front of the car up) in R gear and downhill (front of the car down) in D gear. Since the driver does not need to use the accelerator and brake pedals in creep mode, it means that the vehicle's movement is entirely driven by creep torque. The vehicle controller needs to output coasting recovery negative torque and creep negative torque to control the vehicle to coast or creep. Here, negative torque can be understood as motor recovery torque (to put the battery into a charging state). However, when the battery is fully charged or in a low temperature state, the battery recovery power is very small, resulting in very little available recovery torque for the power system. During creep driving, especially in the scenarios of reverse (front of the car up) in R gear and downhill (front of the car down) in D gear, there will be insufficient braking torque, which will prevent the vehicle speed from being controlled according to the set target, resulting in a rolling phenomenon and creating a safety risk.

[0086] The braking torque control method and vehicle provided in this disclosure, when the difference between the total regenerative torque demand and the maximum motor regenerative torque meets the compensation state conditions, determine the maximum available torque based on the front axle anti-lock braking torque and the rear axle anti-lock braking torque, and determine whether the braking compensation conditions are met based on the maximum motor regenerative torque and the maximum available torque; when the braking compensation conditions are met, determine the front axle distribution torque and the rear axle distribution torque based on the drive mode and the maximum motor regenerative torque; determine the front axle over-limit torque based on the front axle distribution torque and the front axle anti-lock braking torque, and determine the rear axle over-limit torque based on the rear axle distribution torque and the rear axle anti-lock braking torque; and perform braking compensation control based on the drive mode, the rear axle over-limit torque, and the front axle over-limit torque.

[0087] The difference between the total required regenerative torque and the maximum regenerative torque from the motor satisfies the compensation condition, indicating that the motor alone cannot provide sufficient braking torque. The vehicle is in a state requiring torque compensation from the braking system. During braking torque compensation, the maximum available torque is determined to prevent wheel lock-up and driving hazards. If the maximum available torque limits the maximum braking torque, then the braking compensation condition is met, indicating that the braking system needs to participate in braking compensation. During braking compensation, the required braking torque needs to be distributed to different drive axles according to the drive mode. The over-limit torque of different drive axles is determined to ascertain their load conditions, providing data support for braking torque compensation under different drive modes. This prevents wheel lock-up on any drive axle, ensuring the safety of the braking compensation process. The goal is to achieve braking compensation while avoiding wheel lock-up caused by braking compensation, ensuring both deceleration effect and safety during the braking compensation process.

[0088] The braking torque control method provided by the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0089] In some embodiments, as shown in FIG1, a method for controlling braking torque includes:

[0090] Step 101: In response to the fact that the difference between the total demand torque and the maximum motor recovery torque meets the compensation state condition, determine the maximum available torque based on the front axle anti-lock torque and the rear axle anti-lock torque, and determine whether the braking compensation condition is met based on the maximum motor recovery torque and the maximum available torque.

[0091] In practical implementation, when performing brake compensation control, it is necessary to determine whether the corresponding compensation state conditions are met, i.e., whether there is a need for brake compensation at this time. Since brake compensation is the supplementary braking torque provided by the braking system when the motor output torque is insufficient, in order to achieve the corresponding control effect, there is a need for torque compensation only when the motor output torque cannot meet the requirements.

[0092] The maximum regenerative torque represents the maximum regenerative torque value that the motor can output at the current moment, representing the combined output capacity of the power battery and the motor. Because energy recovery involves the motor charging the power battery, the maximum regenerative torque at the time of braking is the minimum of the equivalent torque corresponding to the battery's maximum regenerative power and the equivalent torque corresponding to the motor's maximum generating power. That is, maximum regenerative torque = min(equivalent torque corresponding to the battery's maximum regenerative power, equivalent torque corresponding to the motor's maximum generating power).

[0093] Among them, the equivalent torque corresponding to the maximum energy recovery power of the battery represents the maximum available torque value when the battery recovers energy, indicating the maximum torque capacity that the power battery can use; the equivalent torque corresponding to the maximum power generation power of the motor represents the torque value that the motor can use when running at its maximum power generation power, indicating the maximum torque capacity that the motor can use.

[0094] Taking the minimum value as the maximum motor recovery torque ensures that the motor and power battery will not be damaged when the motor is used for braking output. Generally, the power battery is affected by the ambient temperature, which will reduce the battery's recovery capacity, thereby reducing the battery's maximum recovery power and the maximum motor recovery torque. In this case, the motor alone cannot meet the braking control requirements, and the hydraulic braking torque output by the braking system is needed for torque compensation to achieve braking control that meets the user's needs.

[0095] User demand is expressed using the total regenerative braking torque, which represents the total braking torque required to recover kinetic energy when the vehicle is decelerating or going downhill. If the actual output braking torque is less than the total regenerative braking torque, the user's control needs cannot be met, potentially leading to vehicle rollback or unexpected acceleration.

[0096] By comparing the total required torque A1 and the maximum motor recovered torque A2 (in this embodiment of the disclosure, the interference of torque direction is not considered, and the torque value is used as a positive value for comparison and calculation), it can be determined whether the vehicle meets the state that requires torque compensation. In order to simplify the comparison process, the difference torque ΔA between the total required torque A1 and the maximum motor recovered torque A2 is used to determine whether the compensation state condition is met.

[0097] If ΔA is greater than or equal to the preset torque threshold, it means that the driver is controlling the vehicle in a coasting recovery or creep activation state. The recovery capacity of the battery and motor will limit the recovery function, so the braking system needs to help by using braking compensation to help the VCU control the vehicle speed. ΔA needs to be greater than the torque threshold because if the difference in torque is very small, such as 10 Nm, then it is not worthwhile for the braking system to help, and there will be no problem without braking compensation.

[0098] However, judging whether the compensation state condition is met solely based on a single torque threshold will cause oscillations around the torque threshold during braking compensation control (the New York difference fluctuates around the torque threshold, leading to frequent activation and deactivation of compensation control). To avoid oscillations, a hysteresis handling strategy is used. Specifically, two different torque thresholds, a first torque threshold and a second torque threshold, are used to determine whether the compensation state condition is met. If the first torque threshold is greater than the second torque threshold, the hysteresis interval is the torque range with the first torque threshold as the upper boundary and the second torque threshold as the lower boundary; that is, the hysteresis interval is [second torque threshold, first torque threshold].

[0099] The process of determining whether the compensation state condition is met using the hysteresis strategy is as follows:

[0100] In some embodiments, determining whether the compensation state condition is met based on the difference between the maximum motor recovery torque and the total recovery demand torque includes:

[0101] In response to the differential torque being greater than or equal to a preset first torque threshold, it is determined that the compensation state condition is met.

[0102] In response to the differential torque being less than a preset second torque threshold, it is determined that the compensation state condition is not met;

[0103] Among them, the first torque threshold is greater than the second torque threshold.

[0104] Since the differential torque changes dynamically, the process of determining whether the compensation state condition is met using a hysteresis strategy as the differential torque changes is as follows:

[0105] In response to a differential torque being less than a preset first torque threshold and greater than or equal to a preset second torque threshold, the historical change type of the differential torque is determined;

[0106] If the historical change type changes from less than the second torque threshold to greater than or equal to the second torque threshold, it is determined that the compensation state condition is not met.

[0107] In response to a historical change type that changes from being greater than or equal to a first torque threshold to being less than a first torque threshold, it is determined that the compensation state condition is met.

[0108] In practice, if the difference torque is greater than or equal to the preset first torque threshold, it indicates that the difference torque is large and there is a large braking torque gap. The braking system needs to participate in braking compensation to determine if the compensation state conditions are met.

[0109] If the difference torque is less than the preset second torque threshold, it indicates that the difference torque is small and there is a small braking torque gap. Therefore, the braking system does not need to participate in braking compensation, and the compensation state condition is not met.

[0110] Historical change type (also known as change type) indicates the direction of change of the differential torque from outside the hysteresis interval to inside the hysteresis interval. This includes the increase in differential torque from a value less than the lower boundary of the hysteresis interval to a value greater than the upper boundary of the hysteresis interval to a value greater than the upper boundary of the hysteresis interval.

[0111] If the difference torque is less than the preset first torque threshold and greater than or equal to the preset second torque threshold, further judgment is needed based on the historical change type of the difference torque. If the historical change type of the difference torque is from less than the second torque threshold to greater than or equal to the second torque threshold, that is, when the difference torque changes from less than the second torque threshold to greater than the second torque threshold and is within the hysteresis interval (increasing change), the judgment result before entering the hysteresis interval is still maintained. Since the judgment result when it is less than the second torque threshold is that the compensation state condition is not met, the judgment result remains unchanged at this time, and it is determined that the compensation state condition is not met.

[0112] For example, the first torque threshold is 20 Nm and the second torque threshold is 10 Nm. If the initial value of the difference torque ΔA is 8 Nm, the corresponding initial judgment result is that the compensation state condition is not met. As the vehicle travels, the difference torque changes to 15 Nm. At this time, the historical change type of the difference torque is from less than the second torque threshold to greater than or equal to the second torque threshold, which belongs to the direction of increasing change. Therefore, the original judgment result is maintained, and it is determined that the compensation state condition is not met. Only when the difference torque changes to greater than 20 Nm, the judgment result is changed, and it is determined that the compensation state condition is met.

[0113] If the historical change type is a change from greater than or equal to the first torque threshold to less than the first torque threshold, that is, the difference torque changes from greater than the first torque threshold to less than the first torque threshold and is within the hysteresis interval (a decreasing change), the judgment result before entering the hysteresis interval is still maintained. Since the judgment result when it is greater than the first torque threshold is to satisfy the compensation state condition, the judgment result is kept unchanged at this time, and it is determined that the compensation state condition is satisfied.

[0114] For example, the first torque threshold is 20 Nm and the second torque threshold is 10 Nm. If the initial value of the difference torque ΔA is 25 Nm, the corresponding initial judgment result is that the compensation state condition is met. As the vehicle travels, the difference torque changes to 15 Nm. At this time, the historical change type of the difference torque is from greater than or equal to the first torque threshold to less than the first torque threshold. Then, the original judgment result is maintained, and the compensation state condition is determined to be met. Only when the difference torque changes to less than 10 Nm, the judgment result is changed, and the compensation state condition is determined not to be met.

[0115] Using a hysteresis strategy to determine whether braking compensation conditions are met can effectively avoid frequent changes in the determination results, reduce the occurrence of torque control oscillations during braking compensation control, and improve the safety and effectiveness of braking compensation control.

[0116] After determining that the difference between the total required recovery torque and the maximum motor recovery torque satisfies the compensation condition, the maximum available torque is determined based on the front axle anti-lock torque and the rear axle anti-lock torque. The front axle anti-lock torque represents the maximum braking torque that can be applied to the front drive axle before the front wheels lock up, and the rear axle anti-lock torque represents the maximum braking torque that can be applied to the rear drive axle before the rear wheels lock up. The maximum available torque is the sum of the front axle anti-lock torque and the rear axle anti-lock torque, representing the maximum braking torque value that can be applied before the tires lock up.

[0117] When the wheels are subjected to braking force (including the braking force corresponding to the motor braking torque and the braking force corresponding to the hydraulic braking torque), wheel lock-up may occur. To avoid wheel lock-up, the actual requested braking torque value needs to be less than the maximum available torque. Therefore, when the maximum available torque is less than or equal to the maximum motor recovery torque, it means that the motor's output capacity exceeds the lock-up limit. When performing braking control, it is impossible to distribute all of the maximum motor recovery torque. There will be a certain surplus when distributing the maximum motor recovery torque. The maximum motor recovery torque itself has exceeded the braking capacity of the front and rear drive axles. That is, the braking torque provided by the motor is greater than the maximum required braking torque under the anti-lock braking limit. Therefore, there is no need to use the braking system to compensate for the braking torque, and it is determined that the braking compensation condition is not met.

[0118] If the maximum available torque is greater than the maximum motor recovery torque, it means that the motor's output capacity has not exceeded the anti-lock limit. When performing braking control, all of the maximum motor recovery torque can be distributed. However, if the braking demand cannot be met after distributing all of the maximum motor recovery torque, that is, the braking torque provided by the motor is less than the maximum required braking torque under the anti-lock limit, then the braking system needs to be used to compensate for the braking torque to ensure that the braking compensation conditions are met.

[0119] By determining whether the braking compensation condition is met, it can be determined whether the braking system needs to participate under the constraint of brake lock-up, thus avoiding ineffective braking compensation control. The braking compensation condition indicates the conditions under which the braking system needs to be used for braking torque compensation when the maximum motor regenerative torque cannot meet the braking requirements.

[0120] Optionally, torque compensation control is applied to scenarios where the motor braking is insufficient. In order to avoid control conflicts, torque compensation control is more suitable for scenarios where the current throttle opening is less than the preset opening threshold and the electronic parking system is not activated. The throttle opening being less than the opening threshold ensures that the user does not have a need for rapid acceleration, thus avoiding conflicts between braking compensation and acceleration control. The fact that the electronic parking system is not activated confirms that the user does not have a need for parking and that there is no interference from other braking methods.

[0121] Braking compensation involves the braking system applying additional (non-motor-provided) hydraulic braking torque to the corresponding wheels or drive axle. If the user depresses the accelerator pedal deeply, resulting in a large throttle opening, it indicates a significant acceleration demand. If braking compensation is applied in this situation, the acceleration effect will be insignificant, or even fail. If the conflict between acceleration control and braking compensation control is severe, there is a risk of vehicle loss of control. Furthermore, the purpose of braking compensation control is to compensate for insufficient braking torque. When there is a significant acceleration demand, there is generally no need to compensate for braking torque. Therefore, to ensure the safety and rationality of braking compensation control, it should be implemented when the user does not have a significant braking demand.

[0122] Throttle opening is typically used to assess a user's acceleration needs. The opening threshold represents the maximum throttle opening value at which there will be no control conflict between acceleration needs and braking compensation control. If the current throttle opening is greater than or equal to the opening threshold, it indicates that the user has a significant acceleration need, and braking compensation is not required, thus the triggering condition for braking compensation is not met. If the current throttle opening is less than the opening threshold, it indicates that the user does not have a significant acceleration need, and there is no need to consider the control conflict between braking compensation and acceleration requests, thus the triggering condition for braking compensation is met, and vehicle braking compensation control is allowed.

[0123] Furthermore, the vehicle's braking torque can originate from different systems, such as the torque output by the electric motor, the hydraulic torque applied by the braking system (e.g., ABS), and the mechanical braking torque applied by the electronic parking brake (EPB). Braking compensation is the process by which the braking system supplements the braking torque when the electric motor's output torque is insufficient, in order to achieve the corresponding control effect. Therefore, to avoid conflicts with the EPB parking control process during torque compensation, braking compensation control needs to be performed when the electronic parking brake is not activated (or in a released state). Once the electronic parking brake is activated (or in a clamped state), the torque compensation function is stopped to ensure the safety of the parking control process.

[0124] Throttle opening less than the threshold ensures that the user does not have a need for rapid acceleration, avoiding conflicts between braking compensation and acceleration control. The fact that the electronic parking system is not activated confirms that the user does not have a need for parking and that there is no interference from other braking methods, ensuring the safety of the braking compensation control process.

[0125] Step 102: In response to meeting the braking compensation conditions, determine the front axle distribution torque and the rear axle distribution torque based on the drive mode and the maximum motor regenerative torque.

[0126] In practical implementation, when the braking compensation conditions are met, it indicates a need for torque compensation in the braking system. In this case, the maximum motor recovery torque needs to be distributed according to the drive mode. If the drive mode is four-wheel drive, it means that a portion of the motor braking torque can be distributed to both the front and rear axles. If the maximum motor recovery torque is A2, let A21 represent the front axle distribution torque (the braking torque required from the motor for the front drive axle), and A22 represent the rear axle distribution torque (the braking torque required from the motor for the rear drive axle). If the drive mode is dual-wheel drive, in front-wheel drive dual-wheel drive, the front axle distribution torque = A2, and the rear front axle distribution torque = 0; in rear-wheel drive dual-wheel drive, the front axle distribution torque = 0, and the rear front axle distribution torque = A2.

[0127] Since braking compensation control requires compensating for insufficient torque output from the motor, after determining the torque distribution to the front and rear axles, torque compensation for the front and rear axles can be performed separately based on the locking limit of each drive axle.

[0128] Step 103: Determine the over-limit torque of the front axle based on the front axle distribution torque and the front axle anti-lock braking torque, and determine the over-limit torque of the rear axle based on the rear axle distribution torque and the rear axle anti-lock braking torque.

[0129] In practical implementation, the front axle over-limit torque refers to the maximum torque that can still be distributed to the front axle after applying the front axle distribution torque, without exceeding the front axle anti-lock braking torque limit. The rear axle over-limit torque refers to the maximum torque that can still be distributed to the rear axle after applying the rear axle distribution torque, without exceeding the rear axle anti-lock braking torque limit. The difference between the front axle anti-lock braking torque and the front axle distribution torque is defined as the front axle over-limit torque, i.e., front axle over-limit torque = front axle anti-lock braking torque - front axle distribution torque; the difference between the rear axle anti-lock braking torque and the rear axle distribution torque is defined as the rear axle over-limit torque, i.e., rear axle over-limit torque = rear axle anti-lock braking torque - rear axle distribution torque.

[0130] Specifically, if the front axle over-limit torque is positive, it means the front drive axle can fully utilize the torque distributed to the front axle, and there is still room for torque compensation or torque transfer. If the front axle over-limit torque is negative, it means the front drive axle cannot fully utilize the torque distributed to the front axle, and there is no room for torque compensation or torque transfer; the torque needs to be transferred out or the torque distribution ratio reduced. Similarly, if the rear axle over-limit torque is positive, it means the rear drive axle can fully utilize the torque distributed to the front axle, and there is still room for torque compensation or torque transfer. If the rear axle over-limit torque is negative, it means the rear drive axle cannot fully utilize the torque distributed to the front axle, and there is no room for torque compensation or torque transfer; the torque needs to be transferred out or the torque distribution ratio reduced.

[0131] Step 104: Perform brake compensation control based on the drive mode, rear axle over-limit torque, and front axle over-limit torque.

[0132] In practical implementation, let's take four-wheel drive mode as an example. For instance, if the total torque required for recovery is 120 Nm and the maximum motor recovery torque is 80 Nm, then the maximum torque that needs to be compensated is 40 Nm. The torque distributed to the front axle is 50 Nm, and the torque distributed to the rear axle is 30 Nm. However, the anti-lock braking torque will dynamically change depending on factors such as road surface type and temperature. If the front axle anti-lock braking torque is 40 Nm and the rear axle anti-lock braking torque is 20 Nm, then the maximum usable torque is 60 Nm. At this point, the braking compensation conditions are not met, and the braking system does not need to participate. In this case, the front drive axle is controlled to output the front axle anti-lock braking torque, and the rear drive axle is controlled to output the rear axle anti-lock braking torque. The maximum braking torque that can be provided at this time is the maximum usable torque.

[0133] If the front axle anti-lock braking torque is 40 Nm and the rear axle anti-lock braking torque is 35 Nm, then the maximum usable torque is 75 Nm. At this point, the braking compensation conditions are not met, and no braking system intervention is required. Therefore, the front drive axle is controlled to output the front axle anti-lock braking torque, and the rear drive axle is controlled to output the rear axle anti-lock braking torque. The maximum braking torque that can be provided at this time is the maximum usable torque. Specifically, 5 Nm of the 50 Nm front axle torque allocated to the front drive axle is transferred out, and 5 Nm is transferred to the rear drive axle. After the torque transfer, to avoid wheel lock-up, the front axle torque allocation is 40 Nm and the rear axle torque allocation is 35 Nm. Even then, the maximum motor recovery torque cannot be fully utilized. At this time, no braking system torque compensation is needed. The front drive axle is still controlled to output the front axle anti-lock braking torque, and the rear drive axle is controlled to output the rear axle anti-lock braking torque. The maximum braking torque that can be provided at this time is the maximum usable torque. Therefore, when the braking compensation conditions are not met, the front axle anti-lock braking torque is directly determined as the torque requested by the front axle motor, and the rear axle anti-lock braking torque is determined as the torque requested by the rear axle motor.

[0134] If the front axle anti-lock torque is 40 Nm and the rear axle anti-lock torque is 60 Nm, then the maximum usable torque is 100 Nm. At this time, the maximum usable torque is greater than the maximum motor recovery torque, which meets the braking compensation condition and requires the participation of the braking system. However, at this time, the front axle over-limit torque = front axle anti-lock torque - front axle distributed torque = 40 - 50 = -10 Nm; the rear axle over-limit torque = rear axle anti-lock torque - rear axle distributed torque = 60 - 30 = 30 Nm. The front drive axle cannot fully utilize the torque distributed by the front axle, and the excess torque of the front axle needs to be transferred. Since the maximum available torque is greater than the maximum motor recovery torque, there must be room for torque transfer to the rear drive axle. Therefore, 10 Nm is transferred to the rear drive axle first. After the transfer, the torque distributed by the front axle is 50 Nm, and the torque distributed by the rear axle is 40 Nm. At this time, the excess torque of the rear axle is 60 - 40 = 20 Nm. Since the maximum available torque of 100 Nm is less than the total recovery torque requirement of 120 Nm, the hydraulic compensation torque required by the braking system is 100 - 80 = 20 Nm. After torque transfer control, an additional 20 Nm of hydraulic braking torque is added to the rear drive axle.

[0135] If the front axle anti-lock torque is 60 Nm and the rear axle anti-lock torque is 70 Nm, then the maximum usable torque is 130 Nm. This maximum usable torque exceeds the maximum regenerative braking torque, thus meeting the braking compensation conditions and requiring the braking system to participate. At this point, the front axle over-limit torque = front axle anti-lock torque - front axle distributed torque = 60 - 50 = 10 Nm; the rear axle over-limit torque = rear axle anti-lock torque - rear axle distributed torque = 70 - 30 = 40 Nm. Therefore, the front drive axle can fully utilize the front axle distributed torque without transferring the front axle over-limit torque, and the rear drive axle can also fully utilize the front axle distributed torque without transferring the rear axle over-limit torque. Thus, torque transfer control is unnecessary, and braking compensation control can be performed directly.

[0136] Since the maximum available torque at this point is greater than the total torque required for recovery, the hydraulic compensation torque required is 120 - 80 = 40 Nm. At this point, the upper limit for torque compensation for the front drive axle is 10 Nm of over-limit torque, and the upper limit for torque compensation for the rear drive axle is 40 Nm of over-limit torque. Within these limits, braking compensation control can be performed according to the hydraulic compensation torque requirement using any allocation method. For example, if the ratio of the over-limit torque of the front axle to the over-limit torque of the rear axle is determined to be 1:4, then the hydraulic compensation torque requirement is allocated according to this 1:4 ratio, resulting in 8 Nm compensation for the front drive axle and 32 Nm compensation for the rear drive axle. Therefore, the final braking torque applied to the front drive axle is 50 + 8 = 58 Nm, and the final braking torque applied to the rear drive axle is 30 + 32 = 62 Nm.

[0137] Alternatively, one drive axle can be compensated to the corresponding anti-lock braking torque first, and then the remaining hydraulically compensated torque can be applied to the other drive axle. For example, if 10 Nm of the hydraulically compensated torque is applied to the front drive axle, the final braking torque applied to the front drive axle will be 50 + 10 = 60 Nm. Then, the remaining 30 Nm of the hydraulically compensated torque is applied to the rear drive axle, resulting in a final braking torque of 30 + 30 = 60 Nm applied to the rear drive axle.

[0138] When performing brake compensation, the required braking torque needs to be distributed to different drive axles according to the driving mode. The load condition of different drive axles is determined by determining the over-limit torque of each drive axle. This provides data support for brake torque compensation under different driving modes, avoids wheel lock-up of any drive axle, ensures the safety of the brake compensation process, and achieves brake compensation while avoiding wheel lock-up caused by brake compensation. This ensures both deceleration effect and safety of the brake compensation process.

[0139] In summary, the braking torque control method provided in this disclosure, when determining that braking torque compensation is needed, limits the maximum value of the braking torque by using the maximum available torque, thus preventing wheel lock-up during the braking control process and avoiding driving hazards. Meeting the braking compensation conditions indicates that electric braking cannot complete braking control alone; the braking system needs to participate in braking compensation. During braking compensation, the required braking torque needs to be distributed to different drive axles according to the driving mode, and the load condition of different drive axles is determined by determining the over-limit torque of each drive axle. This avoids wheel lock-up during the braking compensation control process, ensuring the safety of the braking compensation process. It achieves braking compensation while avoiding wheel lock-up caused by braking compensation, ensuring both deceleration effect and safety during the braking compensation process.

[0140] In some embodiments, as shown in FIG2, braking compensation control is performed based on the drive mode, rear axle over-limit torque, and front axle over-limit torque, including:

[0141] Step 201: In response to the drive mode being four-wheel drive mode, determine the hydraulic compensation torque requirement based on the maximum available torque and the total regenerative torque requirement.

[0142] In practice, the hydraulic compensation required torque is the torque that the hydraulic braking system needs to compensate for during braking control. If the drive mode is four-wheel drive, braking compensation control needs to be performed separately for the axle drive and rear drive. Before performing braking compensation control, it is necessary to determine the hydraulic compensation required torque output by the braking system during the compensation control process. The process of determining the hydraulic compensation required torque based on the maximum available torque and the total recovery torque is as follows:

[0143] In some embodiments, determining the hydraulic compensation required torque based on the maximum available torque and the total recoverable torque includes:

[0144] Step 2011: In response to the maximum available torque being greater than or equal to the total recovery demand torque, the difference between the total recovery demand torque and the maximum motor recovery torque is determined as the hydraulic compensation demand torque.

[0145] In practical implementation, when the compensation condition is met, it indicates that the maximum motor regenerative torque is less than the total regenerative torque required. If the maximum available torque is determined to be greater than or equal to the total regenerative torque required, then there exists a situation where the maximum available torque ≥ the total regenerative torque required > the maximum motor regenerative torque. This indicates that the motor's output alone cannot meet the total regenerative torque requirement, necessitating hydraulic braking torque compensation from the braking system. Since the maximum available torque is greater than or equal to the total regenerative torque required at this point, braking compensation control based on the total regenerative torque required will not result in wheel lock-up. Therefore, the difference between the total regenerative torque required and the maximum motor regenerative torque is determined as the hydraulic compensation torque requirement, i.e., hydraulic compensation torque requirement = total regenerative torque required - maximum motor regenerative torque. This provides all the braking torque required for braking control, ensuring good braking performance while avoiding wheel lock-up. It also avoids insufficient braking force caused by low battery temperature or insufficient motor capacity, improving the user's driving experience.

[0146] Step 2012: In response to the fact that the maximum available torque is less than the total recovery torque required, the difference between the maximum available torque and the maximum motor recovery torque is determined as the hydraulic compensation torque required.

[0147] In practical implementation, when the compensation condition is met, it indicates that the maximum motor regenerative torque is less than the total regenerative torque required. If the maximum available torque is determined to be less than the total regenerative torque required, then there exists a situation where the total regenerative torque required > the maximum available torque > the maximum motor regenerative torque. This means that the motor's output alone cannot meet the total regenerative torque requirement, necessitating hydraulic braking torque compensation from the braking system. Since the maximum available torque is less than the total regenerative torque required at this point, braking compensation control based on the total regenerative torque would lead to wheel lock-up. Therefore, the difference between the maximum available torque and the maximum motor regenerative torque is defined as the hydraulic compensation required torque, i.e., hydraulic compensation required torque = maximum available torque - maximum motor regenerative torque. Due to anti-lock braking limitations, only a portion of the braking torque required for braking control can be provided at this time. Torque compensation is performed to the maximum extent possible while avoiding wheel lock-up, ensuring the safety of the braking compensation control process, thus guaranteeing both braking effectiveness and safety, and improving the user's driving experience.

[0148] Step 202: Determine the first torque compensation state for the over-limit torque of the front axle and the second torque compensation state for the over-limit torque of the rear axle.

[0149] In practical implementation, the torque compensation state indicates whether the drive axle can apply additional torque. The first torque compensation state includes the torque over-limit state and the torque surplus state. Since the front axle over-limit torque = front axle anti-lock torque - front axle distributed torque, if the front axle over-limit torque is positive, it means that the front drive axle can fully utilize the front axle distributed torque and there is still room for torque compensation or torque transfer. Therefore, the first torque compensation state of the front axle over-limit torque is the torque surplus state. The torque surplus state indicates that there is room for torque compensation or torque transfer, that is, the front axle can apply additional torque.

[0150] If the front axle over-limit torque is negative, it means that the front drive axle cannot fully utilize the torque distributed by the front axle. There is no space for torque compensation or torque transfer. The torque needs to be transferred out or the torque distribution ratio needs to be reduced. The first torque compensation state of the front axle over-limit torque is the torque over-limit state. The torque over-limit state indicates that there is no space for torque compensation or torque transfer, that is, the front axle cannot apply additional torque.

[0151] Similarly, the second torque compensation state also includes the torque over-limit state and the torque surplus state. Since the rear axle over-limit torque = rear axle anti-lock torque - rear axle distribution torque, if the rear axle over-limit torque is positive, it means that the rear drive axle can make full use of the rear axle distribution torque and there is still room for torque compensation or torque transfer. Therefore, the second torque compensation state of the rear axle over-limit torque is the torque surplus state, that is, the rear axle can apply additional torque.

[0152] If the rear axle over-limit torque is negative, it means that the rear drive axle cannot fully utilize the torque distributed by the rear axle, there is no space for torque compensation or torque transfer, and the torque needs to be transferred out or the torque distribution ratio needs to be reduced. Then the second torque compensation state of the rear axle over-limit torque is the torque over-limit state, that is, the rear axle cannot apply additional torque.

[0153] By determining the first torque compensation state of the front axle over-limit torque and the second torque compensation state of the rear axle over-limit torque, the drive axle with torque compensation or torque transfer space is identified, providing data support for torque transfer control and braking compensation control.

[0154] Step 203: In response to the fact that both the first torque compensation state and the second torque compensation state are in a torque surplus state, brake compensation control is performed based on the hydraulic compensation demand torque, the rear axle over-limit torque, and the front axle over-limit torque.

[0155] In practical implementation, if both the first torque compensation state and the second torque compensation state are in a torque surplus state, it means that the front drive axle still has room for torque compensation after distributing the torque to the front axle, and the rear drive axle also has room for torque compensation after distributing the torque to the rear axle. In this case, there is no need for torque transfer control, and braking compensation control can be performed directly. The braking compensation control process at this time is as follows:

[0156] In some embodiments, brake compensation control is performed based on the hydraulic compensation demand torque, the rear axle over-limit torque, and the front axle over-limit torque, including:

[0157] Step 2031: Determine the sum of the over-limit torque of the rear axle and the over-limit torque of the front axle as the available compensation torque.

[0158] In practical implementation, since both the first torque compensation state and the second torque compensation state are in a torque surplus state, the over-limit torque of the rear axle and the over-limit torque of the front axle are both positive values. At this time, the over-limit torque of the rear axle represents the maximum value of the hydraulic torque that the rear drive axle can distribute, and the over-limit torque of the front axle represents the maximum value of the hydraulic torque that the front drive axle can distribute. Therefore, the sum of the over-limit torque of the rear axle and the over-limit torque of the front axle is the maximum value of the total hydraulic torque that can be distributed. Thus, the sum of the over-limit torque of the rear axle and the over-limit torque of the front axle is determined as the available compensation torque, which represents the maximum value of the total hydraulic torque that can be distributed.

[0159] Step 2032: In response to the available compensation torque being less than or equal to the hydraulic compensation demand torque, the rear axle over-limit torque is determined as the rear axle hydraulic compensation torque, and the front axle over-limit torque is determined as the front axle hydraulic compensation torque.

[0160] In practical implementation, the rear axle hydraulic compensation torque is the torque that the hydraulic braking system needs to compensate for to the rear drive axle during braking control. The front axle hydraulic compensation torque is the torque that the hydraulic braking system needs to compensate for to the front drive axle during braking control. If the available compensation torque is less than or equal to the hydraulic compensation demand torque, it means that it is impossible to distribute all the hydraulic compensation demand torque at this time. And at this time, the hydraulic compensation demand torque = maximum available torque - maximum motor recovery torque. In this case, the available compensation torque equals the hydraulic compensation demand torque. The rear axle over-limit torque is directly determined as the rear axle hydraulic compensation torque, and the front axle over-limit torque is determined as the front axle hydraulic compensation torque. Braking compensation control is performed using the maximum capacity of the front and rear drive axles to provide the maximum braking torque while ensuring that the front and rear wheels do not lock up, thus ensuring the braking control effect.

[0161] For example, if the anti-lock braking torque of the front axle is 60 Nm and the anti-lock braking torque of the rear axle is 40 Nm, then the maximum available torque is 100 Nm. Since the maximum available torque is greater than the maximum regenerative braking torque, the braking compensation condition is met, requiring the participation of the braking system. At this point, the over-limit torque of the front axle = front axle anti-lock braking torque - front axle distributed torque = 60 - 50 = 10 Nm; the over-limit torque of the rear axle = rear axle anti-lock braking torque - rear axle distributed torque = 40 - 30 = 10 Nm. Therefore, the front drive axle can fully utilize the front axle distributed torque without transferring the over-limit torque, and the rear drive axle can also fully utilize the front axle distributed torque without transferring the over-limit torque. Thus, torque transfer control is unnecessary, and braking compensation control can be performed directly. Since the hydraulic compensation torque required at this time = maximum available torque - maximum motor recovery torque = 100 - 80 = 20 Nm, 10 Nm of the 20 Nm is allocated to the front drive axle, and the remaining 10 Nm of the 20 Nm is allocated to the rear drive axle. Therefore, the hydraulic compensation torque of the rear axle at this time is the over-limit torque of the rear axle, and the over-limit torque of the front axle is determined as the hydraulic compensation torque of the front axle.

[0162] Step 2033: In response to the fact that the available compensation torque is greater than the hydraulic compensation demand torque, the hydraulic compensation demand torque is allocated and compensated according to the ratio of the over-limit torque of the rear axle to the over-limit torque of the front axle.

[0163] In practical implementation, if the available compensation torque is greater than the hydraulic compensation demand torque, it means that all the hydraulic compensation demand torque can be distributed. At this time, the hydraulic compensation demand torque = total recovery demand torque - maximum motor recovery torque. Therefore, the available compensation torque is greater than the hydraulic compensation demand torque. The hydraulic compensation demand torque is distributed and compensated according to the ratio of the rear axle over-limit torque to the front axle over-limit torque. Under the premise of ensuring that the front and rear wheels do not lock up, the possibility of wheel lockup is reduced by reasonably distributing the hydraulic compensation demand torque, thus ensuring driving safety.

[0164] For example, if the front axle anti-lock torque is 60 Nm and the rear axle anti-lock torque is 70 Nm, then the maximum available torque is 130 Nm. Since the maximum available torque is greater than the maximum regenerative braking torque, the braking compensation conditions are met, requiring the braking system to participate. At this point, the front axle over-limit torque = front axle anti-lock torque - front axle distributed torque = 60 - 50 = 10 Nm; the rear axle over-limit torque = rear axle anti-lock torque - rear axle distributed torque = 70 - 30 = 40 Nm. Therefore, the available compensation torque = 10 + 40 = 50 Nm, and the hydraulic compensation required torque = 120 - 80 = 40 Nm. Since the available compensation torque is greater than the hydraulic compensation required torque, there is no need to transfer the rear axle over-limit torque; braking compensation control can be performed directly.

[0165] At this point, the upper limit for torque compensation for the front drive axle is 10 Nm of over-limit torque, and the upper limit for torque compensation for the rear drive axle is 40 Nm of over-limit torque. Within these limits, braking compensation control can be performed according to the hydraulic compensation torque requirement using any allocation method. For example, if the ratio of the over-limit torque of the front axle to the over-limit torque of the rear axle is determined to be 1:4, then the hydraulic compensation torque requirement is allocated according to this 1:4 ratio, resulting in 8 Nm compensation for the front drive axle and 32 Nm compensation for the rear drive axle. Therefore, the final braking torque applied to the front drive axle is 50 + 8 = 58 Nm, and the final braking torque applied to the rear drive axle is 30 + 32 = 62 Nm.

[0166] Step 204: In response to the difference between the first torque compensation state and the second torque compensation state, torque transfer control is performed based on the over-limit torque of the rear axle and the over-limit torque of the front axle to obtain the torque transfer result, and braking compensation control is performed based on the torque transfer result and the hydraulic compensation torque requirement.

[0167] In practice, if the first torque compensation state and the second torque compensation state are different, it means that one of the over-limit torque of the rear axle and the over-limit torque of the front axle is positive and the other is negative. That is, there is a drive axle that needs to transfer torque out, and another drive axle can transfer torque in. Therefore, it is necessary to first perform torque transfer control based on the over-limit torque of the rear axle and the over-limit torque of the front axle to obtain the torque transfer result, and then perform braking compensation control based on the torque transfer result and the hydraulic compensation torque requirement.

[0168] When performing brake compensation, the required braking torque needs to be distributed to different drive axles according to the driving mode. The load condition of different drive axles is determined by determining the over-limit torque of each drive axle. This provides data support for brake torque compensation under different driving modes, avoids wheel lock-up of any drive axle, ensures the safety of the brake compensation process, and achieves brake compensation while avoiding wheel lock-up caused by brake compensation. This ensures both deceleration effect and safety of the brake compensation process.

[0169] In some embodiments, as shown in Figure 3, torque transfer control is performed based on the over-limit torque of the rear axle and the over-limit torque of the front axle to obtain torque transfer results, including:

[0170] Step 301: In response to the first torque compensation state being an over-limit state and the second torque compensation state being a remaining state, the front axle anti-lock torque is determined as the front axle motor requested torque, the absolute value of the front axle over-limit torque is transferred to the rear drive axle, and the sum of the absolute values ​​of the rear axle distributed torque and the front axle over-limit torque is determined as the rear axle motor requested torque, thus obtaining the first torque transfer result.

[0171] In specific implementation, for example, if the front axle anti-lock torque is 40 Nm and the rear axle anti-lock torque is 60 Nm, then the maximum available torque is 100 Nm. At this point, the maximum available torque is greater than the maximum motor recovery torque, thus satisfying the braking compensation condition and requiring the participation of the braking system. However, at this time, the front axle over-limit torque = front axle anti-lock torque - front axle distributed torque = 40 - 50 = -10 Nm, so the first torque compensation state is an over-limit state; the rear axle over-limit torque = rear axle anti-lock torque - rear axle distributed torque = 60 - 30 = 30 Nm, so the second torque compensation state is a residual state. The torque transfer control involves transferring 10 Nm to the rear drive axle, resulting in a front axle distributed torque of 50 Nm and a rear axle distributed torque of 40 Nm. The front axle anti-lock torque is then determined as the front axle motor requested torque, and the sum of the absolute values ​​of the rear axle distributed torque and the front axle over-limit torque is determined as the rear axle motor requested torque, thus obtaining the first torque transfer result.

[0172] Step 302: In response to the first torque compensation state being the remaining state and the second torque compensation state being the over-limit state, the rear axle anti-lock torque is determined as the rear axle motor requested torque, the absolute value of the rear axle over-limit torque is transferred to the front drive axle, and the sum of the absolute values ​​of the front axle distributed torque and the rear axle over-limit torque is determined as the front axle motor requested torque, thus obtaining the second torque transfer result.

[0173] In specific implementation, for example, if the front axle anti-lock torque is 70 Nm and the rear axle anti-lock torque is 20 Nm, then the maximum available torque is 90 Nm. At this point, the maximum available torque is greater than the maximum motor recovery torque, thus satisfying the braking compensation condition and requiring the participation of the braking system. However, at this time, the front axle over-limit torque = front axle anti-lock torque - front axle distributed torque = 70 - 50 = 20 Nm, so the first torque compensation state is the residual state; the rear axle over-limit torque = rear axle anti-lock torque - rear axle distributed torque = 20 - 30 = -10 Nm, so the second torque compensation state is the over-limit state. The torque transfer control involves transferring 10 Nm to the front drive axle, resulting in a front axle distributed torque of 60 Nm and a rear axle distributed torque of 30 Nm. The rear axle anti-lock torque is then determined as the rear axle motor requested torque, and the sum of the absolute values ​​of the front axle distributed torque and the rear axle over-limit torque is determined as the front axle motor requested torque, thus obtaining the second torque transfer result.

[0174] Torque transfer is used to avoid wheel lock-up caused by unreasonable motor torque distribution and to provide a basis for brake compensation control after torque transfer.

[0175] In some embodiments, as shown in FIG4, braking compensation control is performed based on the torque transfer result and the hydraulic compensation required torque, including:

[0176] Step 401: Determine the sum of the over-limit torque of the front axle and the over-limit torque of the rear axle as the available remaining torque.

[0177] In practice, since the first torque compensation state and the second torque compensation state are different, the sum of the over-limit torque of the front axle and the over-limit torque of the rear axle is the available remaining torque that can be applied by the receiving party after the torque transfer.

[0178] Step 402: In response to the torque transfer result being the first torque transfer result, and the available remaining torque being less than or equal to the hydraulic compensation demand torque, the available remaining torque is determined as the first hydraulic request torque to be compensated to the rear axle.

[0179] In practice, the torque transfer result is the first torque transfer result, indicating that the front drive axle can no longer perform torque compensation, and only the rear drive axle can be compensated. If the available remaining torque is less than or equal to the hydraulic compensation requirement torque, it means that the space available for torque compensation is insufficient to compensate the total braking torque to the total recovery requirement torque. Only the available remaining torque that can be applied to the rear drive axle after the transfer can be used for compensation. That is, when the available remaining torque is less than or equal to the hydraulic compensation requirement torque, the available remaining torque is determined as the first hydraulic request torque to be compensated to the rear axle, ensuring that the rear wheels will not lock up after the braking compensation control, thus ensuring driving safety.

[0180] Step 403: In response to the torque transfer result being the first torque transfer result, and the available remaining torque being greater than the hydraulic compensation demand torque, the hydraulic compensation demand torque is determined as the first hydraulic request torque to be compensated to the rear axle.

[0181] In practice, the torque transfer result is the first torque transfer result, which means that the front drive axle can no longer perform torque compensation and can only compensate the rear drive axle separately. If the available remaining torque is greater than the hydraulic compensation requirement torque, it means that the space available for torque compensation at this time can compensate the total braking torque to the total recovery requirement torque. In order to achieve the best compensation effect, when the available remaining torque is greater than the hydraulic compensation requirement torque, the hydraulic compensation requirement torque is determined as the first hydraulic request torque to be compensated to the rear axle to meet the braking control requirements.

[0182] Step 404: In response to the torque transfer result being the second torque transfer result, and the available remaining torque being less than or equal to the hydraulic compensation demand torque, the available remaining torque is determined as the second hydraulic request torque to be compensated to the front axle.

[0183] In practice, the torque transfer result is the second torque transfer result, indicating that the rear drive axle can no longer perform torque compensation and can only compensate the front drive axle separately. If the available remaining torque is less than or equal to the hydraulic compensation requirement torque, it means that the space available for torque compensation is insufficient to compensate the total braking torque to the total recovery requirement torque. Compensation can only be performed using the available remaining torque that the front drive axle can apply after the transfer. That is, when the available remaining torque is less than or equal to the hydraulic compensation requirement torque, the available remaining torque is determined as the second hydraulic request torque to be compensated to the front axle, ensuring that the front wheels will not lock up after braking compensation control and ensuring driving safety.

[0184] Step 405: In response to the torque transfer result being the second torque transfer result, and the available remaining torque being greater than the hydraulic compensation demand torque, the hydraulic compensation demand torque is determined as the second hydraulic request torque to be compensated to the front axle.

[0185] In practice, the torque transfer result is the second torque transfer result, which means that the front drive axle can no longer be compensated for torque and can only be compensated separately. If the available remaining torque is greater than the hydraulic compensation required torque, it means that the space available for torque compensation at this time can compensate the total braking torque to the total recovery required torque. In order to achieve the best compensation effect, when the available remaining torque is greater than the hydraulic compensation required torque, the hydraulic compensation required torque is determined as the first hydraulic request torque to be compensated to the front axle to meet the braking control requirements.

[0186] In some embodiments, as shown in FIG5, determining whether the braking compensation condition is met based on the maximum motor regenerative torque and the maximum available torque includes:

[0187] Step 501: In response to the maximum available torque being less than or equal to the maximum motor recovery torque, it is determined that the braking compensation condition is not met.

[0188] In practice, when the maximum available torque is less than or equal to the maximum motor recovery torque, it indicates that the motor's output capacity exceeds the anti-lock limit. When performing braking control, it is impossible to distribute all of the maximum motor recovery torque. There will be a certain surplus when distributing the maximum motor recovery torque. The maximum motor recovery torque itself exceeds the braking capacity of the front and rear drive axles. That is, the braking torque provided by the motor is greater than the maximum required braking torque under the anti-lock limit. Therefore, there is no need to use the braking system to compensate for the braking torque, and it is determined that the braking compensation condition is not met.

[0189] Step 502: In response to the maximum available torque being greater than the maximum motor recovery torque, determine that the braking compensation condition is met.

[0190] In practice, if the maximum available torque is greater than the maximum motor recovery torque, it means that the motor's output capacity has not exceeded the anti-lock limit. When braking control is performed, all of the maximum motor recovery torque can be distributed. However, if the braking demand cannot be met after distributing all of the maximum motor recovery torque, that is, the braking torque provided by the motor is less than the maximum required braking torque under the anti-lock limit, then the braking system needs to be used to compensate for the braking torque to ensure that the braking compensation conditions are met.

[0191] By determining whether the braking compensation conditions are met, it can be determined whether there is a need for the braking system to participate under the constraint of lock-up conditions, thus avoiding ineffective braking compensation control.

[0192] In one embodiment, the method for controlling braking torque further includes:

[0193] In response to the failure to meet the braking compensation conditions, the front axle anti-lock braking torque is determined as the torque requested by the front axle motor, and the rear axle anti-lock braking torque is determined as the torque requested by the rear axle motor.

[0194] In practice, if the braking compensation conditions are not met, it means that the braking torque provided by the motor is greater than the maximum required braking torque under the anti-lock braking limit. In this case, there is no need to use the braking system to compensate for the braking torque. At this time, the front axle anti-lock torque is determined as the torque requested by the front axle motor, and the rear axle anti-lock torque is determined as the torque requested by the rear axle motor. This provides the vehicle with the maximum braking torque and maximizes the braking control effect while avoiding wheel lock-up.

[0195] In some embodiments, as shown in FIG6, the braking compensation control based on the driving mode, the rear axle over-limit torque, and the front axle over-limit torque further includes:

[0196] Step 601: In response to the drive mode being dual drive mode, determine the active drive axle and the driven drive axle in the front drive axle and the rear drive axle, determine the target over-limit torque of the active drive axle in the over-limit torque of the rear axle and the over-limit torque of the front axle, and determine the target torque compensation state of the target over-limit torque.

[0197] In practice, dual-drive modes include rear-wheel drive and front-wheel drive. Front-wheel drive is a drive mode in which the front drive axle is the active drive axle and the rear drive axle is the driven drive axle; rear-wheel drive is a drive mode in which the front drive axle is the driven drive axle and the rear drive axle is the active drive axle.

[0198] When the drive mode is determined to be dual-drive mode, it can be understood that the torque allocated to the driven axle is set to 0, and the maximum motor recovery torque is allocated to the driving axle. Therefore, the target over-limit torque = driving axle anti-lock torque - maximum motor recovery torque (in dual-drive mode, this is the maximum driving axle motor recovery torque), and the driven axle over-limit torque = driven axle anti-lock torque - 0 = driven axle anti-lock torque. If the driving axle anti-lock torque is greater than the maximum motor recovery torque, the target over-limit torque is positive, and the target torque compensation state is in the residual state; if the driving axle anti-lock torque is less than the maximum motor recovery torque, the target over-limit torque is negative, and the target torque compensation state is in the over-limit state. The target axle over-limit torque represents the maximum torque that can still be allocated to the main drive axle after applying the maximum motor recovery torque, without exceeding the main drive axle anti-lock torque limit.

[0199] Step 602: In response to the target torque compensation state being in an over-limit state, torque compensation control is performed on the driven axle based on the target anti-lock torque and total recovery torque demand of the active drive axle.

[0200] In practice, torque compensation control is performed on the driven axle based on the target anti-lock torque and total regenerative braking torque of the active drive axle, including:

[0201] The difference between the total required recovery torque and the anti-lock braking torque of the active drive axle is determined as the dual-drive braking compensation torque.

[0202] In response to the fact that the dual-drive braking compensation torque is greater than the driven drive axle anti-lock torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque.

[0203] In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0204] The target anti-lock braking torque represents the maximum braking torque that can be applied to the main drive axle before the corresponding wheel locks up. If the target torque compensation state is in an over-limit state, it means that the active drive axle can only output the active drive axle anti-lock braking torque (less than the maximum motor recovery torque) before locking up. In this case, the required dual-drive braking compensation torque = total recovery torque demand - active drive axle anti-lock braking torque. If the dual-drive braking compensation torque is greater than the driven drive axle anti-lock braking torque, it means that the driven drive axle cannot compensate for all the dual-drive braking compensation torque to the driven drive axle before locking up, and the driven drive axle anti-lock braking torque is determined as the driven hydraulic request torque. If the dual-drive braking compensation torque is less than or equal to the driven drive axle anti-lock braking torque, it means that the driven drive axle can compensate for all the dual-drive braking compensation torque to the driven drive axle before locking up, and the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0205] Step 603: In response to the target torque compensation state being in the remaining state, torque compensation control is performed on the driven drive axle and / or the active drive axle based on the total required torque and the maximum motor recovery torque.

[0206] In practice, torque compensation control is performed on the driven drive axle and / or the active drive axle based on the total required recovery torque and the maximum motor recovery torque, including:

[0207] The difference between the total required recovery torque and the maximum motor recovery torque is determined as the dual-drive braking compensation torque.

[0208] In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0209] In response to the dual-drive braking compensation torque being greater than the driven drive axle anti-lock torque and less than or equal to the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the difference between the dual-drive braking compensation torque and the driven drive axle anti-lock torque is determined as the active hydraulic compensation torque.

[0210] In response to the fact that the dual-drive braking compensation torque is greater than the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the target over-limit torque is determined as the active hydraulic compensation torque.

[0211] If the target torque compensation state is in the remaining state, it means that the active drive axle can output all the maximum motor recovery torque before locking up, and there is still a part of compensation remaining. At this time, the dual-drive braking compensation torque that needs to be compensated is equal to the total recovery torque demanded minus the maximum motor recovery torque.

[0212] If the dual-drive braking compensation torque is less than or equal to the driven drive axle anti-lock torque, it means that the driven drive axle can compensate all the dual-drive braking compensation torque to the driven drive axle before locking up. The dual-drive braking compensation torque is then determined as the driven hydraulic request torque.

[0213] If the dual-drive braking compensation torque is greater than the driven axle anti-lock torque and less than or equal to the sum of the driven axle anti-lock torque and the target over-limit torque, it means that the remaining parts of the driven and active axles can compensate for all dual-drive braking compensation torque before the wheels lock up. In order to reduce the impact on driving control, torque compensation is given to the driven axle first to avoid the driven axle from locking up. The driven axle anti-lock torque is determined as the driven hydraulic request torque, and the difference between the dual-drive braking compensation torque and the driven axle anti-lock torque is determined as the active hydraulic compensation torque to realize the distribution of dual-drive braking compensation torque.

[0214] If the dual-drive braking compensation torque is greater than the sum of the driven axle anti-lock torque and the target over-limit torque, it means that the remaining parts of the driven and active axles cannot compensate for all the dual-drive braking compensation torque before the wheels lock up. In order to avoid the driven and active axles from locking up, the driven axle anti-lock torque is determined as the driven hydraulic request torque, and the target over-limit torque is determined as the active hydraulic compensation torque. Under the limitation that braking compensation control will not cause wheel lockup, the braking torque is provided to the maximum extent possible to ensure safety and improve the driving experience.

[0215] Furthermore, if the user depresses the brake pedal deeply for an extended period during the braking compensation control process, it is assumed that the user has a parking control requirement. In this case, the motor output braking torque is stopped, and the braking system is directly controlled to output a preset parking hydraulic torque for parking braking control. If the braking system outputs parking hydraulic torque for a longer period than a preset time threshold, it indicates that parking cannot be completed by relying solely on the braking system, and the parking control is abnormal. At the same time, an alarm is triggered, and the electronic parking system is activated to perform parking control.

[0216] It should be noted that the method of this disclosure embodiment can be executed by a single device, such as a computer or server. The method of this embodiment can also be applied to a distributed scenario, where multiple devices cooperate to complete the task. In such a distributed scenario, one of these devices may execute only one or more steps of the method of this disclosure embodiment, and the multiple devices will interact with each other to complete the method described.

[0217] It should be noted that the above description describes some embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0218] Based on the same inventive concept, corresponding to any of the above-described embodiments, this disclosure also provides a braking torque control device.

[0219] Referring to Figure 7, the braking torque control device includes a processor, wherein the processor is configured to execute the following program modules stored in a memory:

[0220] The condition judgment module 10 is configured to: in response to the difference between the total demand torque and the maximum motor recovery torque satisfying the compensation state condition, determine the maximum available torque based on the front axle anti-lock torque and the rear axle anti-lock torque, and determine whether the braking compensation condition is met based on the maximum motor recovery torque and the maximum available torque.

[0221] The torque distribution module 20 is configured to determine the front axle distribution torque and the rear axle distribution torque based on the drive mode and the maximum motor regenerative torque in response to the satisfaction of braking compensation conditions.

[0222] The over-limit calculation module 30 is configured to: determine the over-limit torque of the front axle based on the front axle distribution torque and the front axle anti-lock torque, and determine the over-limit torque of the rear axle based on the rear axle distribution torque and the rear axle anti-lock torque;

[0223] The torque compensation module 40 is configured to perform brake compensation control based on the drive mode, rear axle over-limit torque, and front axle over-limit torque.

[0224] Optionally, the torque compensation module 40 is also configured to:

[0225] In response to the drive mode being four-wheel drive, the hydraulic compensation torque requirement is determined based on the maximum available torque and the total regenerative torque requirement.

[0226] Determine the first torque compensation state for the front axle over-limit torque and the second torque compensation state for the rear axle over-limit torque;

[0227] In response to both the first torque compensation state and the second torque compensation state being in a torque surplus state, braking compensation control is performed based on the hydraulic compensation demand torque, the rear axle over-limit torque, and the front axle over-limit torque.

[0228] In response to the difference between the first torque compensation state and the second torque compensation state, torque transfer control is performed based on the over-limit torque of the rear axle and the over-limit torque of the front axle to obtain the torque transfer result, and braking compensation control is performed based on the torque transfer result and the hydraulic compensation torque requirement.

[0229] Optionally, the torque compensation module 40 is also configured to:

[0230] The sum of the over-limit torque of the rear axle and the over-limit torque of the front axle is determined as the available compensation torque;

[0231] In response to the available compensation torque being less than or equal to the hydraulic compensation demand torque, the rear axle over-limit torque is determined as the rear axle hydraulic compensation torque, and the front axle over-limit torque is determined as the front axle hydraulic compensation torque.

[0232] In response to the fact that the available compensation torque is greater than the hydraulic compensation required torque, the hydraulic compensation required torque is allocated and compensated according to the ratio of the over-limit torque of the rear axle to the over-limit torque of the front axle.

[0233] Optionally, the torque compensation module 40 is also configured to:

[0234] In response to the first torque compensation state being an over-limit state and the second torque compensation state being a remaining state, the anti-lock braking torque of the front axle is determined as the torque requested by the front axle motor, the absolute value of the over-limit torque of the front axle is transferred to the rear drive axle, and the sum of the absolute values ​​of the rear axle distributed torque and the over-limit torque of the front axle is determined as the torque requested by the rear axle motor, thus obtaining the first torque transfer result.

[0235] In response to the first torque compensation state being a residual state and the second torque compensation state being an over-limit state, the rear axle anti-lock torque is determined as the rear axle motor requested torque, the absolute value of the rear axle over-limit torque is transferred to the front drive axle, and the sum of the absolute values ​​of the front axle distributed torque and the rear axle over-limit torque is determined as the front axle motor requested torque, thus obtaining the second torque transfer result.

[0236] Optionally, the torque compensation module 40 is also configured to:

[0237] The sum of the over-limit torque of the front axle and the over-limit torque of the rear axle is determined as the available remaining torque;

[0238] In response to the torque transfer result being the first torque transfer result, and the available remaining torque being less than or equal to the hydraulic compensation demand torque, the available remaining torque is determined as the first hydraulic request torque to be compensated to the rear axle;

[0239] In response to the torque transfer result being the first torque transfer result, and the available remaining torque being greater than the hydraulic compensation demand torque, the hydraulic compensation demand torque is determined as the first hydraulic request torque to be compensated to the rear axle;

[0240] In response to the torque transfer result being the second torque transfer result, and the available remaining torque being less than or equal to the hydraulic compensation demand torque, the available remaining torque is determined as the second hydraulic request torque to be compensated to the front axle;

[0241] In response to the torque transfer result being the second torque transfer result, and the available remaining torque being greater than the hydraulic compensation demand torque, the hydraulic compensation demand torque is determined as the second hydraulic request torque to be compensated to the front axle.

[0242] Optionally, the torque compensation module 40 is also configured to:

[0243] In response to the maximum available torque being greater than or equal to the total recovery demand torque, the difference between the total recovery demand torque and the maximum motor recovery torque is determined as the hydraulic compensation demand torque.

[0244] In response to the maximum available torque being less than the total required recovery torque, the difference between the maximum available torque and the maximum motor recovery torque is determined as the hydraulic compensation required torque.

[0245] Optionally, the condition judgment module 10 is also configured as follows:

[0246] In response to the differential torque being greater than or equal to a preset first torque threshold, it is determined that the compensation state condition is met.

[0247] In response to the differential torque being less than a preset second torque threshold, it is determined that the compensation state condition is not met;

[0248] Among them, the first torque threshold is greater than the second torque threshold.

[0249] Optionally, the condition judgment module 10 is also configured as follows:

[0250] In response to a differential torque being less than a preset first torque threshold and greater than or equal to a preset second torque threshold, the historical change type of the differential torque is determined;

[0251] If the historical change type changes from less than the second torque threshold to greater than or equal to the second torque threshold, it is determined that the compensation state condition is not met.

[0252] In response to a historical change type that changes from being greater than or equal to a first torque threshold to being less than a first torque threshold, it is determined that the compensation state condition is met.

[0253] Optionally, the condition judgment module 10 is also configured as follows:

[0254] The maximum motor recovery torque is the minimum of the equivalent torque corresponding to the maximum battery recovery power and the equivalent torque corresponding to the maximum motor power generation.

[0255] Optionally, the condition judgment module 10 is also configured as follows:

[0256] If the maximum available torque is less than or equal to the maximum motor recovery torque, it is determined that the braking compensation condition is not met.

[0257] The braking compensation condition is determined to be met when the maximum available torque is greater than the maximum motor recovery torque.

[0258] Optionally, the torque compensation module 40 is also configured to:

[0259] In response to the dual-drive mode, the active drive axle and the driven drive axle are determined in the front drive axle and the rear drive axle. The target over-limit torque of the active drive axle is determined in the over-limit torque of the rear axle and the over-limit torque of the front axle, and the target torque compensation state of the target over-limit torque is determined.

[0260] In response to the target torque compensation state being in an over-limit state, torque compensation control is performed on the driven axle based on the target anti-lock torque and total recovery torque demand of the active drive axle.

[0261] In response to the target torque compensation state being in the residual state, torque compensation control is performed on the driven drive axle and / or the active drive axle based on the total required torque and the maximum motor recovery torque.

[0262] Optionally, the torque compensation module 40 is also configured to:

[0263] The difference between the total required recovery torque and the anti-lock braking torque of the active drive axle is determined as the dual-drive braking compensation torque.

[0264] In response to the fact that the dual-drive braking compensation torque is greater than the driven drive axle anti-lock torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque.

[0265] In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0266] Optionally, the torque compensation module 40 is also configured to:

[0267] The difference between the total required recovery torque and the maximum motor recovery torque is determined as the dual-drive braking compensation torque.

[0268] In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

[0269] In response to the dual-drive braking compensation torque being greater than the driven drive axle anti-lock torque and less than or equal to the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the difference between the dual-drive braking compensation torque and the driven drive axle anti-lock torque is determined as the active hydraulic compensation torque.

[0270] In response to the fact that the dual-drive braking compensation torque is greater than the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the target over-limit torque is determined as the active hydraulic compensation torque.

[0271] Optionally, the torque distribution module 20 is also configured to:

[0272] In response to the failure to meet the braking compensation conditions, the front axle anti-lock braking torque is determined as the torque requested by the front axle motor, and the rear axle anti-lock braking torque is determined as the torque requested by the rear axle motor.

[0273] For ease of description, the above apparatus is described in terms of its functions, divided into various modules. Of course, in implementing this disclosure, the functions of each module can be implemented in one or more software and / or hardware.

[0274] The apparatus of the above embodiments is used to implement the corresponding braking torque control method in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0275] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this disclosure also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the braking torque control method described in any of the above embodiments.

[0276] Figure 8 shows a more specific hardware structure diagram of an electronic device provided in this embodiment. The device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, memory 1020, input / output interface 1030, and communication interface 1040 are interconnected within the device via the bus 1050.

[0277] The processor 1010 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0278] The memory 1020 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0279] The input / output interface 1030 is used to connect input / output modules to realize information input and output. Input / output modules can be configured as components within the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touchscreens, microphones, various sensors, etc., while output devices may include displays, speakers, vibrators, indicator lights, etc.

[0280] The communication interface 1040 is used to connect a communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0281] Bus 1050 includes a pathway for transmitting information between various components of the device, such as processor 1010, memory 1020, input / output interface 1030, and communication interface 1040.

[0282] It should be noted that although the above-described device only shows the processor 1010, memory 1020, input / output interface 1030, communication interface 1040, and bus 1050, in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the embodiments of this specification, and not necessarily all the components shown in the figures.

[0283] The electronic devices described above are used to implement the corresponding braking torque control method in any of the foregoing embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0284] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this disclosure also provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to execute the braking torque control method as described in any of the above embodiments.

[0285] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0286] The computer instructions stored in the storage medium of the above embodiments are used to cause the computer to execute the braking torque control method as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0287] Based on the same inventive concept, corresponding to any of the above embodiments, this disclosure also provides a vehicle, including the electronic equipment or braking torque control device of the above embodiments, and executes the braking torque control method as described in any of the above embodiments through the electronic equipment or braking torque control device of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0288] It is understood that before using the technical solutions of the various embodiments in this disclosure, users will be informed of the type, scope of use, and usage scenarios of the personal information involved in an appropriate manner, and user authorization will be obtained.

[0289] For example, upon receiving a user's active request, a prompt message is sent to the user to explicitly inform them that the requested operation will require the acquisition and use of the user's personal information. This allows the user to independently choose, based on the prompt message, whether to provide personal information to the software or hardware such as electronic devices, applications, servers, or storage media performing the operations of this disclosed technical solution.

[0290] As an optional but not limited implementation, in response to a user's active request, sending a prompt message to the user can be done via a pop-up window, where the prompt message can be presented in text format. Furthermore, the pop-up window can also include a selection control allowing the user to choose "agree" or "disagree" to provide personal information to the electronic device.

[0291] It is understood that the above notification and user authorization process are merely illustrative and do not constitute a limitation on the implementation of this disclosure. Other methods that comply with relevant laws and regulations may also be applied to the implementation of this disclosure.

[0292] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure is limited to these examples; within the framework of this disclosure, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this disclosure as described above, which are not provided in detail for the sake of brevity.

[0293] Additionally, to simplify the description and discussion, and to avoid obscuring the embodiments of this disclosure, the provided drawings may or may not show well-known power / ground connections to integrated circuit (IC) chips and other components. Furthermore, the apparatus may be shown in block diagram form to avoid obscuring the embodiments of this disclosure, and this also takes into account the fact that the details of implementation of these block diagram apparatuses are highly dependent on the platform on which the embodiments of this disclosure will be implemented (i.e., these details should be fully understood by those skilled in the art). While specific details (e.g., circuitry) have been set forth to describe exemplary embodiments of this disclosure, it will be apparent to those skilled in the art that the embodiments of this disclosure may be implemented without these specific details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0294] Although this disclosure has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0295] The embodiments disclosed herein are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the claims of this disclosure. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for controlling braking torque, wherein, include: In response to the torque difference between the total demand torque and the maximum motor recovery torque satisfying the compensation state condition, the maximum available torque is determined based on the front axle anti-lock torque and the rear axle anti-lock torque, and it is determined whether the braking compensation condition is met based on the maximum motor recovery torque and the maximum available torque. In response to satisfying the braking compensation condition, the front axle distribution torque and the rear axle distribution torque are determined based on the drive mode and the maximum motor regenerative torque. The over-limit torque of the front axle is determined based on the front axle distribution torque and the front axle anti-lock torque, and the over-limit torque of the rear axle is determined based on the rear axle distribution torque and the rear axle anti-lock torque. Braking compensation control is performed based on the driving mode, the rear axle over-limit torque, and the front axle over-limit torque.

2. The braking torque control method according to claim 1, wherein, The braking compensation control based on the driving mode, the rear axle over-limit torque, and the front axle over-limit torque includes: In response to the drive mode being four-wheel drive mode, the hydraulic compensation torque requirement is determined based on the maximum available torque and the total regenerative torque requirement. Determine the first torque compensation state of the front axle over-limit torque and the second torque compensation state of the rear axle over-limit torque; In response to both the first torque compensation state and the second torque compensation state being in a torque surplus state, the braking compensation control is performed based on the hydraulic compensation demand torque, the rear axle over-limit torque, and the front axle over-limit torque; In response to the difference between the first torque compensation state and the second torque compensation state, torque transfer control is performed based on the over-limit torque of the rear axle and the over-limit torque of the front axle to obtain the torque transfer result, and braking compensation control is performed based on the torque transfer result and the hydraulic compensation required torque.

3. The braking torque control method according to claim 2, wherein, The braking compensation control based on the hydraulic compensation demand torque, the rear axle over-limit torque, and the front axle over-limit torque includes: The sum of the over-limit torque of the rear axle and the over-limit torque of the front axle is determined as the available compensation torque; In response to the available compensation torque being less than or equal to the hydraulic compensation required torque, the rear axle over-limit torque is determined as the rear axle hydraulic compensation torque, and the front axle over-limit torque is determined as the front axle hydraulic compensation torque; In response to the available compensation torque being greater than the hydraulic compensation required torque, the hydraulic compensation required torque is allocated and compensated according to the ratio of the rear axle over-limit torque to the front axle over-limit torque.

4. The braking torque control method according to claim 2, wherein, The torque transfer control based on the over-limit torque of the rear axle and the over-limit torque of the front axle, to obtain the torque transfer result, includes: In response to the first torque compensation state being an over-limit state and the second torque compensation state being a remaining state, the front axle anti-lock torque is determined as the front axle motor requested torque, the absolute value of the front axle over-limit torque is transferred to the rear drive axle, and the sum of the rear axle distributed torque and the absolute value of the front axle over-limit torque is determined as the rear axle motor requested torque, thus obtaining the first torque transfer result; In response to the first torque compensation state being a residual state and the second torque compensation state being an over-limit state, the rear axle anti-lock torque is determined as the rear axle motor requested torque, the absolute value of the rear axle over-limit torque is transferred to the front drive axle, and the sum of the absolute values ​​of the front axle distributed torque and the rear axle over-limit torque is determined as the front axle motor requested torque, thus obtaining the second torque transfer result.

5. The braking torque control method according to claim 4, wherein, The braking compensation control based on the torque transfer result and the hydraulic compensation demand torque includes: The sum of the over-limit torque of the front axle and the over-limit torque of the rear axle is determined as the available remaining torque; In response to the torque transfer result being the first torque transfer result, and the available remaining torque being less than or equal to the hydraulic compensation demand torque, the available remaining torque is determined as the first hydraulic request torque to be compensated to the rear axle; In response to the torque transfer result being the first torque transfer result, and the available remaining torque being greater than the hydraulic compensation required torque, the hydraulic compensation required torque is determined as the first hydraulic request torque to be compensated to the rear axle; In response to the torque transfer result being the second torque transfer result, and the available remaining torque being less than or equal to the hydraulic compensation demand torque, the available remaining torque is determined as the second hydraulic request torque to be compensated to the front axle; In response to the torque transfer result being the second torque transfer result, and the available remaining torque being greater than the hydraulic compensation demand torque, the hydraulic compensation demand torque is determined as the second hydraulic request torque to be compensated to the front axle.

6. The braking torque control method according to claim 2, wherein, The step of determining the hydraulic compensation torque requirement based on the maximum available torque and the total recovery torque requirement includes: In response to the maximum available torque being greater than or equal to the total recovery torque demand, the difference between the total recovery torque demand and the maximum motor recovery torque is determined as the hydraulic compensation torque demand. In response to the maximum available torque being less than the total recovery torque required, the difference between the maximum available torque and the maximum motor recovery torque is determined as the hydraulic compensation torque required.

7. The braking torque control method according to claim 1, wherein, Determining whether the compensation state condition is met based on the difference torque between the maximum motor recovery torque and the total recovery demand torque includes: In response to the differential torque being greater than or equal to a preset first torque threshold, it is determined that the compensation state condition is met; In response to the difference torque being less than a preset second torque threshold, it is determined that the compensation state condition is not met; Wherein, the first torque threshold is greater than the second torque threshold.

8. The braking torque control method according to claim 1, wherein, Determining whether the compensation state condition is met based on the difference torque between the maximum motor recovery torque and the total recovery demand torque includes: In response to the differential torque being less than a preset first torque threshold and greater than or equal to a preset second torque threshold, the historical change type of the differential torque is determined; In response to the historical change type being a change from less than the second torque threshold to greater than or equal to the second torque threshold, it is determined that the compensation state condition is not met; In response to the historical change type changing from greater than or equal to the first torque threshold to less than the first torque threshold, it is determined that the compensation state condition is met.

9. The braking torque control method according to claim 1, wherein, The maximum motor recovery torque is the minimum of the equivalent torque corresponding to the maximum battery recovery power and the equivalent torque corresponding to the maximum motor power generation.

10. The braking torque control method according to claim 1, wherein, The step of determining whether the braking compensation condition is met based on the maximum motor recovery torque and the maximum available torque includes: In response to the maximum available torque being less than or equal to the maximum motor recovery torque, it is determined that the braking compensation condition is not met; In response to the maximum available torque being greater than the maximum motor recovery torque, it is determined that the braking compensation condition is met.

11. The method for controlling braking torque according to claim 1, wherein, The braking compensation control based on the driving mode, the rear axle over-limit torque, and the front axle over-limit torque further includes: In response to the dual-drive mode, the active drive axle and the driven drive axle are determined in the front drive axle and the rear drive axle, the target over-limit torque of the active drive axle is determined in the over-limit torque of the rear axle and the over-limit torque of the front axle, and the target torque compensation state of the target over-limit torque is determined. In response to the target torque compensation state being in an over-limit state, torque compensation control is performed on the driven axle based on the target anti-lock torque of the active drive axle and the total recovery torque demand. In response to the target torque compensation state being in the remaining state, torque compensation control is performed on the driven drive axle and / or the active drive axle based on the total required recovery torque and the maximum motor recovery torque.

12. The braking torque control method according to claim 11, wherein, Torque compensation control of the driven axle is performed based on the target anti-lock torque of the active drive axle and the total regenerative braking torque requirement, including: The difference between the total required torque for recovery and the anti-lock torque of the active drive axle is determined as the dual-drive braking compensation torque. In response to the dual-drive braking compensation torque being greater than the driven drive axle anti-lock torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque; In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque.

13. The braking torque control method according to claim 11, wherein, Torque compensation control is performed on the driven drive axle and / or the driving drive axle based on the total required recovery torque and the maximum motor recovery torque, including: The difference between the total required recovery torque and the maximum motor recovery torque is determined as the dual-drive braking compensation torque; In response to the dual-drive braking compensation torque being less than or equal to the driven drive axle anti-lock torque, the dual-drive braking compensation torque is determined as the driven hydraulic request torque. In response to the dual-drive braking compensation torque being greater than the driven drive axle anti-lock torque and less than or equal to the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the difference between the dual-drive braking compensation torque and the driven drive axle anti-lock torque is determined as the active hydraulic compensation torque. In response to the fact that the dual-drive braking compensation torque is greater than the sum of the driven drive axle anti-lock torque and the target over-limit torque, the driven drive axle anti-lock torque is determined as the driven hydraulic request torque, and the target over-limit torque is determined as the active hydraulic compensation torque.

14. The braking torque control method according to claim 1, wherein, Also includes: In response to the failure to meet the braking compensation conditions, the front axle anti-lock torque is determined as the front axle motor requested torque, and the rear axle anti-lock torque is determined as the rear axle motor requested torque.

15. A vehicle including electronic equipment, wherein, The electronic device includes a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the method as described in any one of claims 1 to 14.

Images