Control method of vehicle and vehicle

Abstract

The application discloses a control method of a vehicle and the vehicle, and belongs to the technical field of hybrid vehicle driving control. Through the technical scheme provided by the embodiment of the application, after it is determined that the slipping working condition is a get-out-of-trouble working condition, the engine is actively released from the torque constraint on the front axle electric driving source, so that the front axle electric driving source can independently output torque and jointly provide driving torque with the rear axle driving source, so that the front axle has sufficient torque output capability when it is necessary to increase torque to cooperate with brake intervention to transfer torque. After the front axle electric driving source is in a non-restricted state, brake intervention is applied to the slipping wheel and the front-rear axle torque distribution is adjusted. The phased control logic enables the brake intervention and torque distribution adjustment to be performed in an environment with sufficient driving force support, thereby more effectively transferring driving torque from the slipping wheel to the same axle side wheel attached to one side, fully utilizing the road adhesion, and thereby improving the get-out-of-trouble capability of the vehicle.

Description

Technical Field

[0001] This application relates to the field of hybrid vehicle drive control technology, and more specifically, to a vehicle control method and a vehicle in the field of hybrid vehicle drive control technology. Background Technology

[0002] In power-split hybrid four-wheel drive vehicles, the front axle houses both the engine and the drive motor, while the rear axle has an independent drive motor. In some power modes, the drive motor operates in a torque-limited state, with its torque constrained by the engine, preventing it from independently outputting its maximum torque. When the vehicle slips on complex road surfaces, if the drive motor is in a torque-limited state, even if the front wheels have sufficient traction, the front axle cannot provide the driving torque to match that traction, thus limiting the vehicle's ability to get out of difficult situations.

[0003] In related technologies, when a vehicle slips, the electronic stability control system typically intervenes with braking to suppress wheel slippage and simultaneously reduces the drive torque of the drive axle containing the slipping wheel. However, when the front axle drive source of the vehicle is in a torque-limited state, if it is necessary to transfer drive torque from the slipping wheel to the wheel on the traction side, the front axle cannot increase the drive torque accordingly due to torque limitation, resulting in insufficient driving force for the entire vehicle.

[0004] The aforementioned issues make it difficult for the vehicle to get out of trouble when the torque of the front axle electric drive source is limited and the vehicle is slipping. Summary of the Invention

[0005] This application provides a vehicle control method and a vehicle that can improve the success rate of vehicle extrication when the torque of the front axle electric drive source is limited. The technical solution is as follows: On the one hand, a vehicle control method is provided, the method comprising: When the front axle electric drive source of the vehicle is in a torque-limited state and the vehicle slips, the slipping condition of the vehicle is determined. The torque-limited state is the state in which the torque output of the front axle electric drive source is constrained by the engine. When the slippage condition is a condition that can get out of trouble, the front axle electric drive source of the vehicle is switched from a torque-limited state to an unlimited state, so that the front axle electric drive source and the rear axle drive source of the vehicle jointly provide driving torque. The unlimited state is the state in which the front axle electric drive source outputs torque independently after being decoupled from the engine. When the front axle electric drive source is in the unrestricted state, braking intervention is applied to the slipping wheel of the vehicle, and the front and rear axle torque distribution is adjusted based on the braking intervention to transfer the drive torque from the slipping wheel to the wheel on the coaxial attached side.

[0006] On one hand, a vehicle control device is provided, the device comprising: The slippage condition determination module is used to determine the slippage condition of the vehicle when the front axle electric drive source of the vehicle is in a torque-limited state and the vehicle slips. The torque-limited state is the state in which the torque output of the front axle electric drive source is constrained by the engine. The switching module is used to switch the front axle electric drive source of the vehicle from a torque-limited state to an unlimited state when the slippage condition is a condition that can get out of trouble, so that the front axle electric drive source and the rear axle drive source of the vehicle jointly provide driving torque. The unlimited state is the state in which the front axle electric drive source outputs torque independently after being decoupled from the engine. An intervention control module is used to apply braking intervention to the slipping wheels of the vehicle when the front axle electric drive source is in the unrestricted state, and adjust the front and rear axle torque distribution based on the braking intervention to transfer the driving torque from the slipping wheels to the wheels on the coaxial attached side.

[0007] On one hand, a vehicle is provided, the vehicle including one or more processors and one or more memories, the one or more memories storing at least one piece of program code, the program code being loaded and executed by the one or more processors to implement a control method for the vehicle.

[0008] On one hand, a computer-readable storage medium is provided, wherein at least one piece of program code is stored in the computer-readable storage medium, the program code being loaded and executed by a processor to implement the vehicle control method.

[0009] The technical solution provided in this application, after determining that the slippage condition is a recoverable condition, actively releases the torque constraint of the engine on the front axle electric drive source, allowing it to output torque independently and jointly provide driving torque with the rear axle drive source. This ensures that the front axle has sufficient torque output capability when it needs to increase torque to coordinate with braking intervention for torque transfer, thus avoiding the problem of insufficient driving force caused by the limited torque of the front axle in traditional solutions. Braking intervention is only applied to the slipping wheel and the torque distribution between the front and rear axles is adjusted after the front axle electric drive source is in an unconstrained state. This phased control logic allows braking intervention and torque distribution adjustment to be carried out in an environment with sufficient driving force support, thereby more effectively transferring driving torque from the slipping wheel to the wheel on the coaxial traction side, making full use of road adhesion. This cooperative control strategy not only improves the vehicle's ability to get out of trouble but also optimizes power transmission efficiency and avoids ineffective energy loss. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the implementation environment of a vehicle control method provided in an embodiment of this application; Figure 2This is a flowchart of a vehicle control method provided in an embodiment of this application; Figure 3 This is a flowchart of another vehicle control method provided in an embodiment of this application; Figure 4 This is a flowchart of another vehicle control method provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of a vehicle control device provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application. Detailed Implementation

[0011] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0012] In the following text, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features reflected. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0013] Hybrid vehicles with power split type generally have multiple drive modes, such as pure electric, series, split, and direct drive modes. Pure electric mode means that the electric motor drives the vehicle. Series mode means that the engine and generator generate electricity and drive the electric motor to drive the vehicle. Split mode means that the engine torque is used to generate electricity and drive the vehicle simultaneously through the planetary gear set at a fixed ratio, and the engine speed and vehicle speed are decoupled. Direct drive means that the engine torque is used to drive the vehicle through the transmission at a fixed speed ratio.

[0014] Vehicle extrication: Current new energy vehicles generally have multiple power modes. When the vehicle is driving on complex road surfaces, such as climbing hills, snow, sand, or potholes, and the rear wheels slip and the vehicle cannot get out of trouble, the front axle has limited torque adjustment capability because the front axle has no torque in the series mode or only uses part of the engine torque in the split mode. At the same time, the rear axle torque is reduced under the control of the chassis controller due to the rear wheel slippage, and the whole vehicle continues to slip and cannot get out of trouble. The customer needs to switch driving modes to get out of trouble, resulting in a poor driving experience.

[0015] In related technologies, during the operation of power-split hybrid four-wheel drive vehicles, the front axle electric drive source cannot independently output its maximum torque under torque-limited conditions. Torque-limited conditions refer to the state where the torque output of the front axle electric drive source is constrained by the engine. When the vehicle slips, even if the front wheels have sufficient road traction, the front axle cannot provide driving torque matching the traction, thus limiting the vehicle's ability to get out of trouble. In related technologies, electronic stability control systems suppress wheel slippage and reduce the driving torque of the drive axle containing the slipping wheel through braking intervention. However, when the torque of the front axle electric drive source is limited, it cannot correspondingly increase the driving torque, resulting in insufficient driving force for the entire vehicle, thereby affecting the vehicle's ability to get out of trouble on complex road surfaces.

[0016] For example, when a vehicle is driving on a wet, muddy road, the front wheels slip due to reduced traction. At this point, the front axle electric drive unit is in a torque-limited state and cannot increase torque output to match the road conditions. Although the rear axle drive unit can provide driving force, the insufficient driving torque of the front axle means the overall vehicle driving force is insufficient to meet the needs of getting out of trouble, and the vehicle remains stationary. Furthermore, in this scenario, the braking intervention of the electronic stability control system can only reduce the driving torque of the slipping wheels. However, because the front axle electric drive unit is constrained by the engine and cannot increase torque, the wheels on the coaxial side cannot receive sufficient driving torque compensation, thus exacerbating the problem of insufficient overall vehicle driving force.

[0017] If the above problems are not solved, the vehicle will not be able to effectively utilize the driving potential of the front axle when the torque of the front axle electric drive source is limited and slipping. The escape operation will fail, the problem of insufficient driving force of the whole vehicle will continue, and the vehicle may be in a dangerous environment for a long time, increasing safety risks and operational complexity.

[0018] Based on this, the technical solutions provided in the embodiments of this application are proposed to at least partially solve the above-mentioned technical problems.

[0019] The implementation environment of the embodiments of this application is described below. See also... Figure 1 The implementation environment of the vehicle control method provided in this application embodiment includes a vehicle controller 101, a power controller 102, and a brake controller 103.

[0020] The vehicle controller 101 is a controller installed on the vehicle. The vehicle controller 101 can acquire relevant information and process the acquired parameters. The vehicle controller 101 is communicatively connected to the power controller 102 and the brake controller 103. The instructions generated by the vehicle controller 101 after processing can be executed by the power controller 102 and the brake controller 103. In some embodiments, the vehicle controller 101 can be implemented as a whole vehicle controller or other types of controllers, or it can be implemented as a combination of different controllers; this application embodiment does not limit this.

[0021] After introducing the implementation environment and application scenarios of the embodiments of this application, the technical solutions provided by the embodiments of this application are described below. (See also...) Figure 2 Taking the vehicle controller as the executing entity as an example, the method includes the following steps.

[0022] 201. When the front axle electric drive source of the vehicle is in a torque-limited state and the vehicle slips, the vehicle controller determines the slipping condition of the vehicle. The torque-limited state is the state in which the torque output of the front axle electric drive source is constrained by the engine.

[0023] The term "vehicle" refers to a power-split hybrid four-wheel-drive vehicle. The front axle houses both an engine and a drive motor, while the rear axle has an independent drive motor. This vehicle structure allows for flexible power distribution and drive mode switching under different operating conditions. The front axle electric drive source refers to the drive motor on the front axle that provides driving force. In certain power modes, the torque output of this electric drive source is constrained by the engine. Torque-limited state refers to an operating state where the torque output of the front axle electric drive source is constrained by the engine. In torque-limited state, even if the front axle electric drive source itself has a higher torque output capability, it cannot independently output its maximum torque; its output torque is limited by the current engine operating state or power coupling mode. In some embodiments, the vehicle is in series or split mode in torque-limited state. Slippage refers to a phenomenon where, during driving or braking, there is a significant deviation between the wheel speed and the actual vehicle speed, causing relative slippage between the wheels and the road surface, resulting in a loss of partial or complete traction.

[0024] 202. When the slippage condition is a condition that can get out of trouble, the vehicle controller switches the front axle electric drive source of the vehicle from a torque-limited state to an unlimited state, so that the front axle electric drive source and the rear axle drive source of the vehicle jointly provide driving torque. The unlimited state is the state in which the front axle electric drive source outputs torque independently after being decoupled from the engine.

[0025] Among these, "slippage condition" refers to the specific operating state of a vehicle when it slips, such as front wheel slippage, rear wheel slippage, or slippage of all wheels. "Escape condition" refers to a slippage condition in which the vehicle can effectively escape a difficult situation through specific control strategies and power distribution adjustments. "Unrestricted state" refers to the operating state where the front axle electric drive source is decoupled from the engine and can independently output torque. In the unrestricted state, the front axle electric drive source is no longer constrained by the engine and can output its maximum torque or the required torque according to control needs. The rear axle drive source refers to the motor or mechanical drive device on the rear axle of the vehicle that provides driving force.

[0026] 203. When the front axle electric drive source is in the unrestricted state, the vehicle controller applies braking intervention to the slipping wheel of the vehicle and adjusts the front and rear axle torque distribution based on the braking intervention to transfer the drive torque from the slipping wheel to the wheel on the coaxial attached side.

[0027] Braking intervention refers to the application of braking torque to specific wheels through the vehicle's braking system. When a vehicle slips, braking intervention is often used to suppress the spinning of the slipping wheel and transfer driving torque to the wheel with better traction. Front and rear axle torque distribution refers to the strategy by which the vehicle control system distributes the total driving torque between the front and rear axles based on current driving conditions and driver intent. Proper torque distribution helps improve the vehicle's traction, stability, and ability to get out of trouble. The wheel on the same axle with better road traction is the wheel on the same drive axle that is opposite the slipping wheel.

[0028] The technical solution provided in this application, after determining that the slippage condition is a recoverable condition, actively releases the torque constraint of the engine on the front axle electric drive source, allowing it to output torque independently and jointly provide driving torque with the rear axle drive source. This ensures that the front axle has sufficient torque output capability when it needs to increase torque to coordinate with braking intervention for torque transfer, thus avoiding the problem of insufficient driving force caused by the limited torque of the front axle in traditional solutions. Braking intervention is only applied to the slipping wheel and the torque distribution between the front and rear axles is adjusted after the front axle electric drive source is in an unconstrained state. This phased control logic allows braking intervention and torque distribution adjustment to be carried out in an environment with sufficient driving force support, thereby more effectively transferring driving torque from the slipping wheel to the wheel on the coaxial traction side, making full use of road adhesion. This cooperative control strategy not only improves the vehicle's ability to get out of trouble but also optimizes power transmission efficiency and avoids ineffective energy loss.

[0029] It should be noted that steps 201-203 above are a simplified description of the vehicle control method provided in the embodiments of this application. The vehicle control method provided in the embodiments of this application will be described in more detail below with some examples. See [link to relevant documentation]. Figure 3 Taking the vehicle controller as the executing entity as an example, the method includes the following steps.

[0030] 301. When the front axle electric drive source of the vehicle is in a torque-limited state and the vehicle slips, the vehicle controller determines the slipping condition of the vehicle. The torque-limited state is the state in which the torque output of the front axle electric drive source is constrained by the engine.

[0031] In one possible implementation, the vehicle controller determines the slip state of each wheel based on the deviation between the wheel speeds of multiple wheels and the vehicle speed. This slip state includes both a gripping state and a slipping state. If at least one front wheel is in a gripping state and at least one rear wheel is in a slipping state, the vehicle controller determines this slipping condition as a condition where the vehicle can escape the entrapment. If all front wheels are in a slipping state, the vehicle controller determines this slipping condition as a condition where escape is not possible or a condition requiring reversing to escape the entrapment.

[0032] Wheel speeds can be acquired in real time using wheel speed sensors installed on each wheel, for example, by detecting pulse signals from the rotating toothed disc using Hall effect sensors or magnetoresistive sensors. Vehicle speed can be obtained in various ways, such as estimation using a Global Positioning System (GPS) module or an Inertial Measurement Unit (IMU), or by weighted averaging of the wheel speeds of all wheels combined with a vehicle motion model. Wheel slippage is a crucial parameter describing the relative motion between the wheel and the road surface, typically categorized as adhesion or slippage. Adhesion indicates good grip between the wheel and the road surface, with the wheel's rotational speed closely matching the vehicle's actual speed. Slippage indicates relative sliding between the wheel and the road surface, with the wheel's rotational speed significantly deviating from the vehicle's actual speed. By comparing the deviation between wheel speed and vehicle speed, this relative motion can be quantified, thus determining whether the wheel is in an adhesion or slippage state. For example, when the deviation between wheel speed and vehicle speed exceeds a certain preset threshold, it can be identified as slippage. A "traffic-free condition" refers to a situation where a vehicle's current slippage can be effectively overcome using a specific control strategy. The determination of a traffic-free condition is based on a real-time assessment of the adhesion distribution between the front and rear axles. When at least one front wheel maintains adhesion to the road surface (i.e., that front wheel has usable traction), while at least one rear wheel is slipping, it indicates that the rear axle's driving force has exceeded the road surface adhesion limit. In this situation, the vehicle has the potential to overcome the obstacle by providing additional driving force through the front axle. This determination mechanism accurately identifies scenarios suitable for the traffic-free strategy proposed in this application, avoiding ineffective operations when the conditions for overcoming the obstacle are not met. A "traffic-free condition" or "reverse-to-traffic-free condition" refers to a situation where the vehicle's current slippage is unsuitable for overcoming the obstacle by providing additional driving force through the front axle. When all the vehicle's front wheels are slipping, it means the front axle cannot provide effective driving force, and even switching the front axle's electric drive source will not provide sufficient adhesion to propel the vehicle forward. In this situation, the vehicle may need to employ other extrication strategies, such as reversing to escape the predicament, which involves using the traction of the rear wheels to attempt to move backward. This assessment can promptly halt inapplicable extrication attempts, avoid unnecessary energy waste, and provide the driver with alternative extrication suggestions.

[0033] By differentiating between traction-capable, traction-uncapable, and reversing-to-traction conditions through the above implementation methods, the switching of the front axle electric drive source and subsequent braking intervention and torque distribution adjustment are only activated in scenarios with traction potential. This avoids ineffective power output and energy waste when traction conditions are not met. Simultaneously, in extreme cases where the front wheels are completely slipping, the system can promptly identify and guide the driver to adopt other traction strategies, improving the vehicle's overall traction capability and driving safety under complex road conditions. This condition determination mechanism makes the vehicle's traction strategy more intelligent and efficient, avoids unnecessary power waste, and improves the vehicle's adaptability to harsh road conditions.

[0034] To provide a clearer explanation of the above embodiments, the embodiments will be described in several parts below.

[0035] Part 1: The vehicle controller determines the slip state of each wheel based on the deviation between the wheel speed of the multiple wheels and the vehicle speed.

[0036] In one possible implementation, for any one of the plurality of wheels, the vehicle controller compares the wheel speed of that wheel with the vehicle speed. If the deviation between the wheel speed and the vehicle speed is less than a calibrated threshold, the vehicle controller determines that the wheel's slip state is an adhesion state. If the deviation between the wheel speed and the vehicle speed is greater than or equal to the calibrated threshold, the vehicle controller determines that the wheel's slip state is a skid state.

[0037] The term "multiple wheels" refers to all the wheels on a vehicle used for driving or support, typically including the front and rear wheels. These wheels generate driving or braking forces through contact with the road surface, and their motion directly reflects the interaction between the vehicle and the road. Wheel speed refers to the rotational speed of a single wheel, and its variation is closely related to the vehicle's acceleration, deceleration, and slippage. Vehicle speed represents the actual motion of the vehicle and is the benchmark for judging whether wheel slippage has occurred. The deviation refers to the difference between the wheel speed and the vehicle speed. This deviation can be expressed as an absolute difference, a relative difference, or a percentage difference. The magnitude of the deviation directly reflects the degree of slippage between the wheel and the road surface and is the core basis for judging the wheel slippage state. The slippage state refers to the relative motion state of the wheel when in contact with the road surface, including adhesion and slippage states. Adhesion refers to the existence of sufficient friction between the wheel and the road surface, with the wheel's rotational speed essentially consistent with the vehicle's actual driving speed, or in other words, no significant relative slippage between the wheel and the road surface. In this state, the wheel can effectively transmit driving or braking forces. Slippage refers to insufficient friction between the wheels and the road surface, causing a significant difference between the wheel's rotational speed and the vehicle's actual speed; in other words, the wheels spin freely or lock up on the road. Slippage reduces the vehicle's driving efficiency and handling stability. The calibration threshold is a preset value used to distinguish between wheel adhesion and slippage. This calibration threshold is determined through experimental testing and engineering calibration based on factors such as vehicle type, tire characteristics, road conditions, and driving experience. For example, the calibration threshold can be a wheel speed difference (e.g., 2 km / h) or a slip ratio percentage (e.g., 5%). The calibration threshold can also be dynamically adjusted, for example, based on real-time parameters such as the road friction coefficient and vehicle load, to adapt to different operating conditions.

[0038] By comparing the wheel speed of each wheel with the vehicle speed and making judgments based on preset calibration thresholds, the adhesion and slippage states of the wheels can be accurately distinguished. This judgment rule avoids misjudgments of slippage states caused by ambiguous judgment boundaries in traditional methods, improving the accuracy and reliability of slippage state identification. Accurate slippage state information is the foundation for subsequent slippage condition judgments (such as the identification of traction-free conditions) and vehicle traction control strategies (such as front axle electric drive source state switching and braking intervention), thereby ensuring that the vehicle can take appropriate traction measures under complex road conditions, improving the vehicle's driving safety and traction capabilities.

[0039] To provide a clearer explanation of the above embodiments, the method of comparing the wheel speed of the wheel with the vehicle speed in the above embodiments will be described below.

[0040] In one possible implementation, the vehicle controller compares the vehicle speed with a minimum calibrated speed. If the vehicle speed is lower than the minimum calibrated speed, the vehicle controller compares the wheel speed of each wheel with a preset wheel speed threshold instead of comparing the wheel speed with the vehicle speed. The preset wheel speed threshold is a wheel speed limit used to determine whether the wheel is in the traction state at low vehicle speeds. If the vehicle speed is greater than or equal to the minimum calibrated speed, the vehicle controller compares the wheel speed of each wheel with the minimum calibrated speed.

[0041] The comparison between vehicle speed and a minimum calibrated speed aims to initially classify operating conditions based on the vehicle's current speed. The minimum calibrated speed is an empirical value or a speed threshold obtained through experimental calibration, used to distinguish between low-speed operating conditions where speed measurement accuracy is affected and regular-speed operating conditions where measurement accuracy is relatively reliable. When the vehicle speed is lower than the minimum calibrated speed, the wheel speed is compared with a preset wheel speed threshold instead of directly comparing the wheel speed with the vehicle speed. The preset wheel speed threshold is a wheel speed limit specifically set for judging wheel slippage under low-speed conditions. Because vehicle speed sensors may have significant errors at low speeds, directly comparing with the vehicle speed would lead to inaccurate judgments. Therefore, the above implementation introduces a preset wheel speed threshold, which can be calibrated through extensive experimental data, simulation analysis, or expert experience to ensure that at low speeds, when the wheel speed exceeds this threshold, it can be reliably determined that the wheel is slipping, without relying on inaccurate real-time vehicle speed. For example, this threshold can be set to 2 km / h or 3 km / h. When the wheel speed exceeds this value, slippage can be effectively identified even if the vehicle speed sensor reading is inaccurate. When the vehicle speed is greater than or equal to the minimum calibrated speed, the wheel speed is compared with the overall vehicle speed. When the vehicle is traveling at medium to high speeds or high speeds, the measurement accuracy of the vehicle speed sensor is usually high, and the speed data accurately reflects the actual motion state of the vehicle. Therefore, under these conditions, directly comparing the wheel speeds of each wheel with the overall vehicle speed allows for the calculation of the wheel speed difference or slip ratio, thereby determining whether the wheels are slipping. This method utilizes the high reliability of vehicle speed data under normal operating conditions, avoids introducing additional judgment logic, and maintains the directness and efficiency of the judgment.

[0042] By implementing the above methods, introducing a minimum calibrated vehicle speed and a preset wheel speed threshold, and dynamically selecting the comparison method based on the vehicle speed range, it is possible to ensure more accurate and reliable judgment of wheel slippage under various vehicle speed conditions, especially at low speeds. This slippage judgment provides a solid foundation for subsequent determination of slippage conditions and traction control, improving the vehicle's ability to get out of trouble and driving safety under complex road conditions, and avoiding control failure or inefficiency caused by misjudgment.

[0043] The second part states that when at least one front wheel among the plurality of wheels is in an traction state and at least one rear wheel among the plurality of wheels is in a slipping state, the vehicle controller determines that the slipping condition is the condition that can get out of trouble.

[0044] In one possible implementation, when at least one front wheel is in an traction state and at least one rear wheel is in a slipping state, the vehicle controller starts timing. If the timing duration exceeds a first timing duration threshold, and the at least one front wheel remains in an traction state while the at least one rear wheel remains in a slipping state, the vehicle controller determines that the slipping condition is the traction-free condition.

[0045] The initiation timing mechanism aims to launch a time measurement process to assess the persistence of a specific vehicle state, avoiding decisions based on instantaneous states and thus improving the accuracy and robustness of condition determination. This timing process can be implemented through a timer module within the vehicle controller. When specific conditions are met, the vehicle controller sends a start signal to the timer, causing it to accumulate time from zero. Alternatively, it can be implemented using a software counter. Within each control cycle, if the conditions are continuously met, the counter value increments until the conditions are no longer met or a preset value is reached. The first timing duration threshold is a preset time length used to determine whether a specific vehicle slippage state has sufficient persistence, preventing instantaneous or brief slippage phenomena from being misjudged as stable conditions requiring extrication. This first timing duration threshold can be stored as a system parameter in the non-volatile memory of the vehicle control unit and set during vehicle calibration based on actual test data and experience, for example, set to 0.5 seconds, 1 second, or 2 seconds. Furthermore, the first timing threshold can also be dynamically adjusted, for example, calculated in real time through table lookup or algorithm based on parameters such as the vehicle's current speed and estimated road friction coefficient, to adapt to different driving environments. The concepts of "continuous adhesion" and "continuous slippage" emphasize the stability of wheel slippage over a period of time, rather than its instantaneous nature. During the timing process, the slippage state of the relevant wheels must remain within the preset adhesion or slippage range to ensure the reliability of the condition determination. During the timing process, the vehicle controller continuously monitors the slippage state of each wheel. If, during this period, any front wheel determined to be in an adhesion state briefly enters a slippage state, or any rear wheel determined to be in a slippage state briefly enters an adhesion state, the timer will be reset or stopped, indicating that the continuity condition is not met. The vehicle controller can also set a small tolerance window to allow for very short, slight fluctuations in the state during the continuity determination period. However, if the fluctuation exceeds the preset tolerance range or duration, the continuity is considered interrupted. Determining the slippage condition as a recoverable condition is the final assessment of the vehicle's current driving status. It indicates that the vehicle is in a specific slippage situation where it can effectively escape the predicament by switching the front axle electric drive source to an unrestricted state and adjusting torque distribution. This assessment is a prerequisite for implementing subsequent escape strategies. When the timing duration exceeds a first timing threshold, and during the entire timing period, at least one front wheel remains in an traction state while at least one rear wheel remains in a slippage state, the vehicle control unit sets an internal flag indicating that the current condition is a recoverable condition.

[0046] In the above implementation method, timing begins when at least one front wheel is in an traction state and at least one rear wheel is in a slipping state. Only when the timing duration exceeds a first timing duration threshold, and at least one front wheel remains in an traction state while at least one rear wheel remains in a slipping state, is the slipping condition determined to be a drivable condition. This mechanism, which introduces duration judgment, filters out instantaneous or brief wheel slip states, avoiding unnecessary switching of the front axle electric drive source state due to misjudgment, thereby improving the accuracy and reliability of condition determination. By ensuring that control strategy adjustments are only made when the vehicle is indeed in a stable and continuous drivable state, frequent operation and wear of power transmission components are reduced, unnecessary energy consumption is lowered, and the vehicle's driving stability under complex road conditions is further guaranteed.

[0047] For example, the vehicle controller continuously receives data from wheel speed sensors and, combined with the vehicle's speed information, calculates the slip ratio of each wheel in real time to determine whether the slip state is one of traction or slippage. For instance, when the vehicle controller detects that the left front wheel is in a traction state while the right rear wheel is slipping, a timer module inside the controller is activated and begins accumulating time. During this timing process, the vehicle controller continuously monitors the slip state of all wheels. If, during this period, the left front wheel remains in a traction state and the right rear wheel remains in a slipping state, and the accumulated time of the timer reaches a preset first timing threshold (e.g., set to 1.5 seconds), then the vehicle controller will send a signal confirming the current slippage condition as a condition suitable for escaping trouble. Conversely, if the left front wheel briefly slips or the right rear wheel briefly regains traction during the timing process, the timer will be reset, and the timing will only restart once the conditions are met again. This mechanism ensures that subsequent escaping control strategies are only triggered when the vehicle's slippage state is stable and continuously meets the escaping conditions.

[0048] Optionally, the vehicle controller can also perform the following steps.

[0049] In one possible implementation, when the slippage condition is a reversing escape condition, the vehicle controller generates a reversing escape prompt message. The vehicle controller outputs this reversing escape prompt message to guide the driver to switch to reverse gear and use the rear wheel traction to escape the situation.

[0050] The "reversing to escape a stuck situation" refers to a specific condition where a vehicle can escape a stuck situation by reversing. This typically occurs when both the front wheels of the vehicle are slipping, and reversing allows the rear wheels to maintain traction and extricate the vehicle from the predicament. For example, a vehicle may be stuck in mud or snow, with the front wheels losing traction, but the road conditions behind it are better; in this case, reversing can provide an opportunity to escape. Generating a reversing to escape prompt information means automatically creating or selecting a message based on the current vehicle status and conditions to inform the driver that reversing is the appropriate action to escape the situation. This prompt information can be in various forms, such as text, graphics, or voice commands. For example, it can generate a text prompt like "Please engage reverse gear and slowly reverse to escape the stuck situation," or play a corresponding voice prompt. Another approach is to pre-set multiple prompt templates for different reversing to escape scenarios. When a specific reversing to escape situation is identified, the appropriate template is selected and filled to generate the final prompt information. Outputting this reversing to escape prompt information means presenting the generated prompt information to the driver through the vehicle's human-machine interface (HMI). This can be achieved in several ways, such as displaying text or graphic information on the vehicle's dashboard or central control screen; playing voice prompts through the in-car audio system; or using other sensory cues such as vibration and lights. The goal is to ensure that the driver receives timely and clear guidance on how to get out of trouble. Guiding the driver to switch to reverse gear to utilize the rear wheel traction for extrication means using the aforementioned prompts to help the driver understand the vehicle's current predicament and the correct extrication strategy, and then follow the instructions. In certain slippery conditions, the front wheels may completely lose traction. However, when reversing, the vehicle's center of gravity and the direction of driving force may change, allowing the rear wheels to gain better traction and provide sufficient driving force to help the vehicle escape the predicament. For example, when the front wheels are stuck in a pothole, reversing can use the traction of the rear wheels to pull the vehicle out of the pothole.

[0051] Through the above implementation method, by generating and outputting clear reversing and getting out of trouble prompts, drivers can quickly understand the current predicament of their vehicle and the correct get-out strategy, avoiding blind attempts or missing the best time to get out of trouble. This not only improves the efficiency and success rate of getting out of trouble under specific slippery conditions, but also optimizes the driver's user experience, enabling them to cope more calmly in complex road conditions.

[0052] For example, when a vehicle is driving on a wet or muddy road, if all the front wheels experience severe slippage and the vehicle cannot extricate itself using forward drive, the system will determine that it is in a reversing mode to escape the predicament based on preset logic. For instance, the vehicle controller might detect that the deviation between the front wheel speed and the vehicle speed consistently exceeds a certain calibrated threshold, and the overall vehicle speed is low or stationary. Once this condition is confirmed, the vehicle controller generates a reversing warning message. This message can be displayed as text on the vehicle's central control screen, such as "Front wheels are slipping severely, please engage reverse gear and slowly extricate yourself," while simultaneously playing a voice prompt through the vehicle's audio system: "Please note that the front wheels are slipping. We recommend shifting to reverse gear and using the rear wheel traction to extricate yourself." Upon receiving these clear prompts, the driver will shift the transmission to reverse gear as instructed and attempt to reverse slowly. Because the vehicle's center of gravity and the direction of driving force may change when reversing, the rear wheels may gain sufficient traction on surfaces with relatively better grip, thus helping the vehicle successfully escape the predicament.

[0053] Optionally, before the vehicle controller determines the vehicle's slip condition, it can also acquire the vehicle's accelerator pedal opening and vehicle speed. If the accelerator pedal opening is greater than a pedal opening threshold and the vehicle speed is less than a vehicle speed threshold, the step of determining the vehicle's slip condition is executed.

[0054] The vehicle speed threshold can be calibrated based on vehicle type, chassis tuning, tire characteristics, and typical off-road scenarios. For example, for a typical family hybrid SUV, the speed threshold can be calibrated to 10 km / h or 15 km / h; for a rugged off-road vehicle, the speed threshold can be appropriately relaxed to 20 km / h. The pedal opening threshold can be calibrated to 30%, 40%, or 50%, representing a clear acceleration request from the driver. The joint judgment logic of the two conditions is an "AND" relationship, meaning that the subsequent slippage condition judgment process is only allowed when both the vehicle speed is low and the driver has a strong acceleration intention.

[0055] Through the above implementation method, it is possible to identify low-speed, high-throttle scenarios where the driver has a clear need to get out of trouble, while effectively excluding scenarios that should not trigger the get-out-of-trouble function, such as high-speed slippage and non-active acceleration. This avoids the false triggering of the intelligent get-out-of-trouble function, reduces unnecessary computational burden and energy consumption, and more importantly, eliminates the safety hazards that may be caused by switching power modes under excessive vehicle speed or non-active acceleration.

[0056] 302. When the slippage condition is a condition that can be overcome, the vehicle controller switches the front axle electric drive source of the vehicle from a torque-limited state to an unlimited state, so that the front axle electric drive source and the rear axle drive source of the vehicle jointly provide driving torque. The unlimited state is the state in which the front axle electric drive source outputs torque independently after being decoupled from the engine.

[0057] In situations where the vehicle can escape difficult conditions, the vehicle controller will control the vehicle to enter the intelligent escape mode / intelligent escape condition. When the front axle electric drive source and the rear axle drive source of the vehicle jointly provide drive torque, the vehicle is actually switched to electric four-wheel drive mode (EV four-wheel drive mode).

[0058] In one possible implementation, when the slippage condition is a recoverable condition, the vehicle controller disconnects the power transmission path between the vehicle's engine and the front axle electric drive source, thereby decoupling the front axle electric drive source from the engine. The vehicle controller then engages the drive path from the front axle electric drive source to the front wheels, allowing the front axle electric drive source to independently drive the front wheels in this unrestricted state.

[0059] Disconnecting the power transmission path between the vehicle's engine and the front axle electric drive source aims to completely sever the engine's torque constraint on the front axle electric drive source, allowing it to output torque independently. In some embodiments, this can be achieved by controlling the engine to stop torque output and disengaging the first clutch between the engine and the front axle electric drive source. Alternatively, the vehicle controller can send a command to the engine management system (EMS) to put the engine into idle or shut-off mode, while simultaneously controlling clutch disengagement via hydraulic or electromagnetic actuators. Furthermore, a separable gear set or planetary gear mechanism can be used, disengaging it via an electronically controlled actuator to disconnect the power transmission. Engaging the drive path from the front axle electric drive source to the front wheels ensures that the torque independently output by the front axle electric drive source can be effectively transmitted to the front wheels. In some embodiments, this can be achieved by controlling the front axle electric drive source to enter a torque output preparation state and then closing the second clutch between the front axle electric drive source and the front wheels. Alternatively, the vehicle controller can activate the power electronics module of the front axle electric drive source to prepare it for torque output and control clutch engagement via electromagnetic or hydraulic actuators. If the vehicle uses an integrated electric drive axle, the motor controller can be directly activated to output torque.

[0060] Through the above implementation method, and by clearly defining the decoupling and engagement steps, the problems of unclear switching processes in traditional solutions, which may lead to decoupling failure or ineffective torque transmission, are solved. This allows the front axle electric drive source to smoothly release torque constraints and reliably enter an unrestricted state of independent torque output. This ensures that, under vehicle slippage conditions, the front axle electric drive source can work in conjunction with the rear axle drive source to provide sufficient driving torque, improving the vehicle's ability to get out of trouble and enhancing driving safety.

[0061] To provide a clearer explanation of the above embodiments, the embodiments will be described in several parts below.

[0062] Part 1: The vehicle controller disconnects the power transmission path between the vehicle's engine and the front axle electric drive source.

[0063] In one possible implementation, the vehicle controller controls the engine to stop torque output. When the engine stops outputting torque, the vehicle controller releases a first clutch between the engine and the front axle electric drive source, thereby disconnecting the power transmission path between the engine and the front axle electric drive source.

[0064] Controlling the engine to stop torque output refers to sending a command to the engine through the vehicle's powertrain control system (such as the engine control unit) to stop or significantly reduce torque output. This can be achieved in several ways. For example, the engine can be controlled to enter a fuel cut-off mode, i.e., fuel injection is suspended, allowing the engine to gradually stop outputting torque under inertia. Alternatively, parameters such as the engine's throttle opening and ignition timing can be adjusted to reduce the output torque to a preset extremely low level, thereby eliminating the load on the power transmission path. Releasing the first clutch between the engine and the front axle electric drive source means disengaging the first clutch through a clutch actuator, thus physically disconnecting the power connection between the engine and the front axle electric drive source. For example, a hydraulically driven clutch actuator can be used, controlling the hydraulic circuit to cause the clutch release fork to push the pressure plate and driven plate apart. Alternatively, an electric actuator can be used, with a motor driving a mechanical structure to achieve the clutch disengagement operation.

[0065] By implementing the above method, first controlling the engine to stop torque output and then releasing the first clutch, the first clutch disengages under no-load or very low-load conditions, improving the smoothness of the power switching process and avoiding impact and damage to transmission components, thereby extending the service life of the first clutch and related transmission components. This allows the front axle electric drive source to switch from a torque-limited state to an unlimited state more smoothly and reliably, providing a solid foundation for the vehicle to get out of trouble under slippery conditions, and improving the overall vehicle's ability to get out of trouble and the user experience.

[0066] For example, when it is determined that the front axle electric drive source needs to be switched from a torque-limited state to an unlimited state, the vehicle controller sends a command to the engine control unit, requesting the engine to stop outputting torque. Upon receiving the command, the engine control unit executes a fuel cut-off strategy, stopping fuel injection into the engine cylinders, causing the engine to stop generating drive torque for a short period due to the loss of power input. After confirming that the engine torque output has dropped to zero or a preset extremely low value, the vehicle controller further sends a disengagement command to the actuator of the first clutch. For example, if the first clutch is hydraulically controlled, the hydraulic actuator will drive the clutch disengagement fork, completely disengaging the pressure plate and driven plate of the first clutch, thereby completely disconnecting the mechanical connection between the engine and the front axle electric drive source.

[0067] Part Two: The vehicle controller engages the front axle electric drive source with the drive path to the front wheels.

[0068] In one possible implementation, the vehicle controller controls the front axle electric drive source to enter a torque output preparation state. After the front axle electric drive source enters the torque output preparation state, the vehicle controller closes a second clutch disposed between the front axle electric drive source and the front wheel to engage the drive path between the front axle electric drive source and the front wheel.

[0069] The control of the front axle electric drive source into a torque output preparation state aims to ensure that the electric drive source is in optimal operating condition before engaging with the front wheels, thereby avoiding excessive shock during engagement of the power transmission path. This can include the vehicle controller sending commands to the electric drive source controller to pre-activate its internal power electronics (such as the inverter) and pre-excite the motor windings, positioning the rotor to be ready to respond to torque commands. Furthermore, key parameters such as motor temperature and insulation status can be monitored to ensure they are within safe ranges, and necessary pre-charging, preheating, or self-test procedures can be performed. Alternatively, this preparation state can be achieved by adjusting the electric drive source's control parameters, such as current, voltage, or frequency, to enter a low-torque output or standby mode, preparing for smooth engagement. Closing the second clutch located between the front axle electric drive source and the front wheels establishes a mechanical connection between them, enabling efficient power transmission. This second clutch can be a hydraulically controlled clutch, using a hydraulic pump and valves to precisely control the engagement and disengagement of the clutch pressure plate for smooth torque transmission. Alternatively, the second clutch can be an electromagnetically controlled clutch, which uses an electromagnetic coil to generate magnetic force to attract or release the clutch plates, thereby engaging the drive path. Furthermore, a mechanical clutch can be used, where an actuator (such as a small motor or cable) drives a shift fork to control clutch engagement.

[0070] By implementing the above method, first putting the front axle electric drive source into torque output preparation state before engaging the second clutch, the smoothness and reliability of the power transmission path engagement are ensured. This not only protects the transmission components from excessive impact and extends their service life, but also ensures that the front axle electric drive source can output torque stably and efficiently, providing a solid and stable power foundation for the vehicle to effectively get out of trouble under slippery conditions, thus improving the vehicle's ability to get out of trouble and the smoothness of driving.

[0071] Optionally, the vehicle controller can also perform the following steps.

[0072] In one possible implementation, the vehicle controller obtains the remaining battery power of the vehicle. The vehicle controller compares the remaining battery power with a first power threshold. If the remaining battery power is lower than the first power threshold, the vehicle controller limits the duration of the front axle electric drive source in the unrestricted state to no more than a preset duration.

[0073] Obtaining the vehicle's remaining battery power refers to real-time monitoring and acquisition of the currently available electrical energy reserves in the vehicle's power battery. This ensures that subsequent power management decisions are based on the accurate current battery state. One implementation involves the vehicle's Battery Management System (BMS) collecting real-time battery operating data through voltage, current, and temperature sensors integrated within the battery pack. This data, combined with a pre-defined battery model and algorithm, estimates the battery's State of Charge (SOC), typically expressed as a percentage. Another implementation involves the vehicle controller directly reading the remaining battery power data reported by the BMS through a communication interface. This data can be in the form of a percentage of charge, available energy value, or driving range. Comparing the remaining battery power with a first power threshold involves comparing the real-time acquired remaining battery power with a pre-set threshold value. The purpose of this comparison is to determine whether the current battery power is sufficient to safely support the front axle electric drive source in an unconstrained state for an extended period. When the remaining battery charge is below a first charge threshold, limiting the duration of the front axle electric drive unit's unrestricted state to no more than a preset duration means that when the battery charge is below a preset threshold, the time the front axle electric drive unit operates in an unrestricted state is forcibly limited. This limitation aims to prevent over-discharge of the battery, protect battery life, and ensure that it can still provide short-term off-road capability when the battery charge is low. One implementation is that when the vehicle controller detects that the remaining battery charge is below the first charge threshold and the front axle electric drive unit is switched to an unrestricted state, it starts an internal timer. This timer continuously records the time the front axle electric drive unit is in the unrestricted state. Once the timer reaches the preset duration (e.g., 60 seconds), the vehicle controller will forcibly instruct the front axle electric drive unit to switch from the unrestricted state back to the torque-limited state, or reduce its output power to a safe level to avoid over-discharge of the battery. Another implementation is that the vehicle controller dynamically adjusts the maximum output power or energy limit of the front axle electric drive unit in the unrestricted state based on the remaining battery charge and the preset duration, so that its total output energy does not exceed a certain safe value within the preset duration, thereby indirectly limiting the duration.

[0074] By intelligently limiting the duration of the front axle electric drive source in an unrestricted state, the system avoids prolonged high-power output from the battery when its charge is low, thereby extending battery life and improving vehicle reliability. Simultaneously, because short periods of unrestricted output are still permitted, the vehicle can still obtain the necessary driving force during emergency escape maneuvers, ensuring the effectiveness of the escape function and achieving a good balance between battery protection and vehicle traction performance.

[0075] For example, if a vehicle skids on a complex road surface, the vehicle controller determines it's a situation where it can get out of trouble and switches the front axle electric drive unit from a torque-limited state to an unlimited state. At this time, the vehicle's battery management system continuously monitors the state of charge (SOC) of the battery pack and reports the remaining battery charge to the vehicle controller in real time. For example, the current remaining battery charge is 30%. The vehicle controller has a preset first charge threshold of 35%. After receiving the 30% remaining battery charge data, the PCU compares it with 35% and determines that the current remaining battery charge is below the first charge threshold. Because the remaining battery charge is below 35%, the vehicle controller activates a duration-limiting strategy. If the front axle electric drive unit is switched to an unlimited state for extrication, the vehicle controller starts an internal timer that records the time the front axle electric drive unit is in the unlimited state. The preset duration is set to, for example, 60 seconds. Once the timer reaches 60 seconds, the vehicle controller will forcibly instruct the front axle electric drive unit to switch back from the unlimited state to the torque-limited state, or reduce its output power to prevent excessive battery discharge.

[0076] Optionally, based on the above implementation method, the following steps can also be performed.

[0077] In one possible implementation, the vehicle controller compares the remaining battery charge with a second charge threshold, which is less than the first charge threshold. If the remaining battery charge is lower than the second charge threshold, the vehicle controller switches the front axle electric drive source from the unrestricted state back to the torque-restricted state.

[0078] The comparison of the remaining battery charge with a second charge threshold aims to monitor and evaluate the vehicle's battery status in real time to determine whether a critical point has been reached requiring stricter charge management measures. The second charge threshold is a preset charge value lower than the first charge threshold, representing an extremely low battery charge level. This characteristic of the second charge threshold being lower than the first charge threshold clarifies the relative magnitude of the two thresholds; that is, the second charge threshold is a lower charge threshold. The first charge threshold is typically used to trigger strategies that limit the duration of the unrestricted state, while the second charge threshold is used to trigger more urgent charge protection strategies. For example, the first charge threshold can be set at 20% of the total battery capacity, while the second charge threshold can be set at 10% or 5% of the total battery capacity. This tiered threshold setting allows the vehicle to adopt differentiated management strategies based on different battery charge levels, thereby balancing the need for getting out of trouble with maximizing battery safety and the vehicle's basic functions. When the remaining battery charge is below the second charge threshold, switching the front axle electric drive source from the unrestricted state back to the torque-limited state is a core protective measure taken when the battery charge reaches an extremely low level. When the remaining battery charge is below the second charge threshold, it indicates that the battery is on the verge of severe depletion. Continuing to maintain the unrestricted state of the front axle electric drive source (i.e., independent high-power torque output) will cause irreversible damage to the battery and may lead to vehicle breakdown. Therefore, a switching operation is performed to forcibly switch the front axle electric drive source from the unrestricted state of independent torque output back to the torque-limited state where torque is constrained by the engine. This switching can be achieved by controlling the power output mode of the front axle electric drive source, disconnecting its independent drive path from the front wheels (e.g., by releasing the second clutch), and re-establishing a power transmission path with the engine (e.g., by engaging the first clutch and controlling the engine output torque). Another implementation is to directly limit the maximum output torque of the front axle electric drive source, preventing it from independently providing high torque output, thereby simulating the torque-limited state and reducing power consumption.

[0079] Through the above implementation method, by introducing a second battery power threshold and setting it to be lower than the first battery power threshold, a more refined and secure battery power classification management mechanism is established. When the remaining battery power is lower than the second battery power threshold, the front axle electric drive source can be switched from a high-energy-consuming unrestricted state to a torque-limited state in a timely and decisive manner, thereby quickly terminating high-power power consumption. This strategy not only avoids deep battery discharge and protects battery life, but also prioritizes the limited battery power for the vehicle's basic driving functions and critical electrical systems, preventing the vehicle from breaking down due to battery depletion and improving the vehicle's operational reliability and safety under extremely low battery conditions.

[0080] For example, after receiving the remaining battery charge, the vehicle controller compares it with a pre-stored first and second charge threshold. The first threshold is set to 20% of the total battery capacity, and the second threshold to 8%. When the remaining battery charge drops from 25% to 18% (below the first threshold but above the second), the vehicle controller starts a timer and limits the maximum continuous operating time of the front axle electric drive unit in the unrestricted state, for example, to 5 minutes. During this period, if the vehicle successfully escapes the obstacle, it returns to normal mode. If it fails to escape and the timer expires, the front axle electric drive unit switches back to torque-limited mode. If the remaining battery charge further decreases during the escape process, for example, from 18% to 7% (below the second threshold), the vehicle controller will issue a command to forcibly switch the front axle electric drive unit from the unrestricted state back to the torque-limited state. For example, the vehicle controller can send a command to the powertrain control unit, requesting it to disengage the second clutch between the front axle electric drive unit and the front wheels, and control the engine to re-engage the first clutch, so that the torque output of the front axle electric drive unit is again constrained by the engine. At the same time, the power output of the front axle electric drive source will be limited to a low level to minimize power consumption.

[0081] Optionally, the vehicle controller can also perform the following steps.

[0082] In one possible implementation, the vehicle controller monitors the vehicle's sensor and communication status. Upon detecting a sensor malfunction or communication interruption, the vehicle controller disables the switching of the front axle electric drive source from the torque-limited state to the unlimited state. After disabling the switching, the vehicle controller reverts to the vehicle's electronic stability control system's basic traction control mode, which is a control mode that does not coordinate the braking intervention with the front-to-rear axle torque distribution.

[0083] Monitoring the vehicle's sensor and communication status involves real-time checks on the operation of various sensors (such as wheel speed sensors, steering angle sensors, acceleration sensors, and torque sensors) used to perceive the environment and the vehicle's own operational status, ensuring the accuracy and reliability of their data output. Real-time checks are also conducted on data transmission links between control units within the vehicle or between the vehicle and external systems to ensure timely, complete, and error-free data transmission. As a specific implementation method, sensor malfunctions can be determined by periodically reading diagnostic fault codes (DTCs) from sensors or by comparing the consistency of data measured by different sensors (redundant sensors) for the same physical quantity. For example, wheel speed sensors can be assessed for anomalies by comparing the reasonableness of the wheel speed signals from all four wheels. Furthermore, the health of the communication link can be evaluated by monitoring parameters such as data frame loss rate, error frame rate, and bus load rate on the vehicle's internal communication bus (e.g., CAN bus, FlexRay bus, Ethernet). For example, if a control unit fails to receive the expected data frame within a specified time, it can be considered a communication interruption. In the event of a detected sensor malfunction or communication interruption, the switching of the front axle electric drive source from a torque-limited state to an unlimited state is disabled. This is intended to prevent the execution of complex control logic that could lead to loss of vehicle control or unsafe conditions when system information is unreliable or control commands cannot be effectively transmitted. Disabling the switching means that even if the conditions for escaping a difficult situation are met, the front axle electric drive source will not switch from an engine-constrained torque-limited state to an independently output torque-unlimited state. As one specific implementation, upon detecting a fault, the vehicle controller can send a "disable switching" command to the actuator responsible for switching the front axle electric drive source state (e.g., the clutch controller), or directly prevent the logic conditions that trigger the switching. Alternatively, a fault flag can be set at the software level; once this flag is set, the control module associated with the front axle electric drive source state switching will stop operating or be bypassed, thereby preventing the state switching from occurring. After disabling the switching, reverting to the basic traction control mode of the vehicle's electronic stability control system provides a safe retreat mechanism. When advanced traction control fails due to abnormal conditions, the vehicle can revert to a well-proven, relatively simple, and reliable basic control mode to maintain basic vehicle controllability. As one implementation, the vehicle controller can preset a priority mechanism that automatically lowers the priority of the currently operating traction control mode and activates the preset basic traction control (TCS) mode in the Electronic Stability Control (ESC) system when a sensor or communication failure is detected. Alternatively, a specific command can be sent to the ESC controller to switch it from the advanced intelligent traction control mode to the basic TCS mode.This command triggers the mode-switching logic within the ESC controller, enabling basic braking intervention and torque limiting strategies. This basic traction control mode is one that does not coordinate braking intervention with front-to-rear axle torque distribution, clearly defining its characteristics: it does not involve complex coordination strategies for braking intervention and front-to-rear axle torque distribution. This mode typically only applies braking to slipping wheels and may reduce the torque output of the entire drive axle, but it does not actively perform cross-axle or intra-axle torque transfer. Its control logic is relatively simple, and it has lower requirements for sensor data and communication reliability.

[0084] Through the above implementation methods, when the vehicle is in trouble-free control, abnormal situations such as sensor malfunctions or communication interruptions can be detected and responded to in a timely manner. This avoids executing complex trouble-free strategies when information is inaccurate or control commands cannot be effectively transmitted, thereby effectively preventing driving safety risks caused by control logic disorder, torque output errors, or improper braking actions. The above implementation methods provide a reliable safety retreat mechanism, ensuring that when advanced trouble-free functions are limited, the vehicle can still return to a basic and stable traction control mode, improving the vehicle's safety and reliability under complex operating conditions.

[0085] For example, when a power-split hybrid four-wheel-drive vehicle skids on an icy or snowy road, the vehicle controller, based on information from wheel speed sensors and vehicle speed sensors, determines that the situation is conducive to getting out of trouble and prepares to switch the front axle electric drive source from a torque-constrained state (where torque is limited by the engine) to an unconstrained state (where torque is independently output), in order to coordinate with braking intervention and front-to-rear axle torque distribution to extricate the vehicle from the predicament. Before executing this switch, the vehicle controller continuously monitors the status of each sensor and the CAN bus communication status. If the vehicle controller detects an abnormality in a wheel speed sensor signal (e.g., signal loss or output value exceeding a reasonable range), or if the error frame rate on the CAN bus suddenly increases, indicating a communication interruption or instability, the vehicle controller determines that the system is in an abnormal state. The vehicle controller sends a command to the vehicle controller (HCU) to disable the state switching of the front axle electric drive source, preventing it from transitioning from a torque-limited state to an unconstrained state. The vehicle controller then sends a command to the electronic stability control (ESC) system to switch it back from advanced traction control mode (involving braking intervention and coordinated front-to-rear axle torque distribution) to basic traction control (TCS) mode. In this basic TCS mode, the ESC system only applies braking to the slipping wheels and may reduce total torque output through the engine management system (EMS), but it does not execute complex front and rear axle torque distribution strategies. In this way, even if advanced traction control is not possible, the vehicle can still obtain basic traction control, avoiding loss of control due to erroneous control.

[0086] 303. The vehicle controller adjusts the gears of the vehicle's front axle transmission.

[0087] In one possible implementation, the vehicle controller obtains the current gear of the vehicle's front axle transmission. If the current gear is not the target gear, the vehicle controller shifts the front axle transmission to the target gear, which is the gear that provides the front wheels with a higher wheel-side torque output than the current gear. If the current gear is the target gear, the vehicle controller maintains the current gear.

[0088] The current gear position of the front axle transmission is the basis for subsequent judgments on whether the current gear meets the requirements for getting out of trouble and whether a gear shift is necessary. In some embodiments, this can be obtained via the vehicle's Controller Area Network (CAN) bus, where the vehicle controller sends a query command to the unit responsible for controlling the front axle transmission (e.g., the transmission control unit, TCU) to receive and parse the current gear position data. Alternatively, a position sensor or encoder can be installed inside the front axle transmission to directly detect the meshing state of the transmission gear set and transmit the detected electrical signal to the vehicle controller for processing to determine the current gear position. Shifting the front axle transmission to the target gear means that when it is determined that the current gear does not meet the torque output requirements for getting out of trouble, the front axle transmission is actively adjusted to a gear that can provide better drive torque. In some embodiments, the vehicle controller can send a specific shift command to the transmission control unit (TCU). After receiving the command, the TCU changes the meshing relationship of the gears inside the transmission through its internal hydraulic actuators, solenoid valves, or motors, thereby achieving gear shifting. For some highly integrated electric drive axle systems, the controller of the electric drive source can directly manage its internal multi-speed reducer or transmission, achieving gear switching by controlling the matching of motor speed and reduction ratio. The target gear is not a fixed value, but a dynamically determined gear designed to optimize the front-wheel drive torque output. Typically, in situations requiring high torque output for getting out of trouble, the target gear will be a low gear with a large gear ratio (e.g., first or second gear), because a lower gear can amplify the torque output from the front axle electric drive source through the mechanical transmission system, thereby generating greater wheel-side drive torque. The vehicle controller can pre-store a mapping table of gears and corresponding wheel-side torque output capabilities. During runtime, it looks up the table based on the current gear and selects a gear that can provide greater wheel-side torque as the target. Alternatively, the vehicle controller can calculate the wheel-side torque output capability of the current gear in real time and compare it with a preset minimum wheel-side torque threshold required for getting out of trouble, selecting a gear that meets or exceeds that threshold as the target gear. Maintaining the current gear aims to avoid unnecessary gear shifts when the current gear in the front axle transmission already meets the torque output requirements for escaping difficult situations. This helps maintain the smoothness and continuity of vehicle power output, reduces mechanical wear and shock in the transmission system, and simplifies control logic. This can be achieved by incorporating a control strategy in the vehicle controller that, when it determines the current gear meets the target gear requirements, either refrains from sending any shift command to the front axle transmission control unit (TCU) or sends an explicit command to maintain the current gear.

[0089] Through the above implementation method, by obtaining the current gear of the front axle transmission and determining whether to switch to a target gear that can provide greater wheel-side torque output based on the need for getting out of trouble, it is ensured that the front axle electric drive source can fully utilize its driving potential. This allows the front axle to provide strong driving torque that matches the road surface adhesion under slipping conditions, improving the vehicle's ability to get out of trouble. At the same time, when the current gear meets the requirements, the gear remains unchanged, avoiding unnecessary gear shifting operations, ensuring the smoothness and continuity of power output, and reducing shock and wear in the transmission system.

[0090] For example, when the front axle electric drive source is detected to have switched from a torque-limited state to an unlimited state, and the drive path from the front axle electric drive source to the front wheels has been successfully engaged, the vehicle controller executes a gear check and adjustment process. For instance, the vehicle controller sends a request to the front axle transmission control unit (TCU) via the vehicle's CAN bus to obtain the current gear information of the front axle transmission, such as 3rd gear. The vehicle controller has a preset target gear strategy for traction situations, which typically sets 1st or 2nd gear as the target gear because these lower gears have a larger gear ratio, amplifying the torque of the electric drive source and providing greater wheel-side torque. If the VCU sets 1st gear as the target gear, it will find that the current gear (3rd gear) does not match the target gear (1st gear). The vehicle controller sends a shift command to the TCU, instructing the TCU to shift the front axle transmission from 3rd gear to 1st gear. After receiving the command, the TCU completes the gear shift through its internal hydraulic or electromagnetic actuators. After the switch is complete, the front axle electric drive unit can output wheel-side torque far greater than that in third gear through the first gear ratio, thus providing the vehicle with powerful traction for getting out of trouble. Conversely, if the vehicle controller detects that the current gear is already first gear, which matches the target gear, the vehicle controller will not send any shift command, but will keep the current first gear unchanged, ensuring that the front axle electric drive unit continues to operate at its maximum torque output capacity, avoiding unnecessary power interruption.

[0091] 304. When the front axle electric drive source is in the unrestricted state, the vehicle controller applies braking intervention to the slipping wheel of the vehicle and adjusts the front and rear axle torque distribution based on the braking intervention to transfer the drive torque from the slipping wheel to the wheel on the coaxial attached side.

[0092] In one possible implementation, the vehicle controller applies braking intervention to the slipping wheel, generating a braking torque opposite to the direction of the drive torque to alter the torque distribution between the slipping wheel and the wheel on the coaxial side, such that the drive torque of the slipping wheel is at least partially transferred to the wheel on the coaxial side. Based on the amount of this drive torque transfer, the vehicle controller adjusts the front and rear axle torque distribution.

[0093] Applying braking intervention to a slipping wheel refers to using the vehicle's braking system to apply braking torque to a specific wheel to actively control its rotation. The core of applying braking intervention lies in applying a braking torque to the slipping wheel that is opposite in direction to the current driving torque; its basic function is to suppress excessive wheel spin. As one possible implementation, the vehicle's Electronic Stability Control (ESC) or Traction Control System (TCS) can utilize its integrated brake actuator, such as a hydraulic braking unit, to apply braking pressure to the brakes of the slipping wheel according to control commands, thereby generating the required braking torque. As another possible implementation, the vehicle can be equipped with a brake-by-wire system, which can directly receive commands from the vehicle controller and control the brakes with high precision and rapid response to achieve braking intervention on the slipping wheel. This involves changing the torque distribution between the slipping wheel and the wheel on the same axle, so that the driving torque of the slipping wheel is at least partially transferred to the wheel on the same axle, describing the redistribution of driving torque between the left and right wheels on the same axle through braking intervention. The basic principle is based on the characteristics of a vehicle differential. When the speed of one wheel (the slipping wheel) decreases due to braking, the differential transfers more drive torque to the other wheel on the same axle (the traction wheel). As one possible implementation, when the vehicle is equipped with an open differential, braking intervention reduces the speed of the slipping wheel, and the differential mechanism naturally transfers more torque to the traction wheel on the same axle, which has a higher speed. Another possible implementation is with advanced differentials such as limited-slip differentials (LSD) or electronic differential locks (EDL). These devices, in conjunction with braking intervention, can more actively and effectively transfer drive torque from the slipping wheel to the traction wheel on the same axle with better traction. Adjusting the front and rear axle torque distribution based on this transfer of drive torque means dynamically adjusting the proportion of total drive torque borne by the front and rear axles according to the actual amount of drive torque transferred from the slipping wheel to the traction wheel on the same axle. This ensures that the vehicle's driving force matches the current road surface traction conditions. One possible implementation is that the vehicle controller acquires information on the drive torque transfer in real time, recalculates the target torque output of the front axle electric drive source and the rear axle drive source according to a preset control algorithm, and sends corresponding control commands to them. Another possible implementation is that the vehicle controller presets a series of torque distribution strategy maps, looks up the new front and rear axle torque distribution ratio based on the real-time detected drive torque transfer, and controls the torque output of the front axle electric drive source and the rear axle drive source accordingly.

[0094] By applying braking torque in the opposite direction to the driving torque to the slipping wheel, the excess driving torque of the slipping wheel can be precisely counteracted, suppressing its spinning. Utilizing the inherent characteristics of the vehicle's differential mechanism, the driving torque is at least partially transferred from the slipping wheel to the wheel with traction on the same axle. This mechanism ensures that driving torque that might otherwise be wasted due to slippage is effectively utilized and transferred to the wheel with traction, thus fully exploiting the traction potential of each wheel. Adjusting the front and rear axle torque distribution based on the actual amount of driving torque transfer ensures that the total driving torque required by each axle is matched. This avoids insufficient or excessive torque output, ensuring that the front axle electric drive source and the rear axle drive source can work together to output the optimal driving torque that matches the current road surface traction. Especially when the front axle electric drive source is in an unrestricted state, its independent torque output capability can be fully utilized, ensuring that the total driving force of the vehicle meets the requirements for getting out of trouble.

[0095] To provide a clearer explanation of the above embodiments, the embodiments will be described in several parts below.

[0096] Part 1: The vehicle controller applies braking intervention to the slipping wheel.

[0097] In one possible implementation, the vehicle controller acquires the real-time slip ratio of the slipping wheel. If the real-time slip ratio is greater than a target slip ratio, the vehicle controller increases the braking torque corresponding to the slipping wheel. If the real-time slip ratio is less than or equal to the target slip ratio, the vehicle controller decreases the braking torque corresponding to the slipping wheel.

[0098] Real-time slip ratio reflects the relative motion between the wheel and the road surface and is the basis for dynamically adjusting braking torque. Real-time slip ratio can be obtained in several ways. For example, it can be measured using wheel speed sensors (such as Hall effect sensors or photoelectric encoders) and combined with the vehicle's actual speed (which can be estimated using GPS, IMU, or the speed of non-driving wheels). The specific formula is: Slip ratio = (Wheel linear velocity - Vehicle speed) / Vehicle speed. Alternatively, it can be estimated more accurately using the algorithm module within the vehicle's Electronic Stability Control (ESC) or Traction Control System (TCS) by fusing data from multiple sensors (such as wheel speed, acceleration, and yaw rate). When the real-time slip ratio exceeds the target slip ratio, the braking torque corresponding to the slipping wheel needs to be increased. The principle is that when the wheel slip exceeds a preset target value, it indicates that the current braking intervention is insufficient to effectively suppress wheel slip. In this case, the braking intervention needs to be increased to more effectively transfer the driving torque to the wheel on the coaxial side. Increasing braking torque can be achieved by controlling the vehicle's braking system. For example, controlling the actuators in a hydraulic braking system or brake-by-wire system can increase the brake fluid pressure or the brake motor current, thereby increasing the clamping force of the brake calipers on the brake discs and thus increasing the braking torque. Another approach is to use a tiered increase strategy, increasing the braking torque proportionally or in segments based on the difference between the real-time slip ratio and the target slip ratio, to achieve more precise control. When the real-time slip ratio is less than or equal to the target slip ratio, the braking torque corresponding to the slipping wheel needs to be reduced. The principle is that when the wheel slippage is effectively controlled or has fallen below the preset target value, braking intervention should be appropriately reduced to avoid excessive braking that causes unnecessary power waste and vehicle instability. Reducing braking torque can also be achieved by controlling the vehicle's braking system actuators. For example, reducing the brake fluid pressure or the brake motor current can reduce the clamping force of the brake calipers on the brake discs and thus reduce the braking torque. As another approach, a gradual reduction strategy can be adopted, progressively reducing the braking torque until the minimum braking torque required to maintain the target slip ratio is reached, or the braking intervention can be completely released when slippage is completely eliminated.

[0099] Through the above implementation method, the applied braking torque can be dynamically adjusted according to the actual degree of slippage of the slipping wheel, solving the problems of excessive braking torque leading to power waste or insufficient braking torque failing to effectively suppress slippage in traditional solutions. By controlling braking intervention, the driving torque can be efficiently and smoothly transferred from the slipping wheel to the wheel on the coaxial side, thereby improving the vehicle's ability to get out of trouble in complex road conditions, while optimizing energy utilization efficiency and avoiding unnecessary power loss.

[0100] For example, the vehicle controller continuously receives real-time data from the wheel speed sensors of each wheel. Based on this wheel speed data and the estimated vehicle speed, the vehicle controller calculates the real-time slip ratio of each wheel. If the preset target slip ratio is 10%, when the vehicle controller detects that the real-time slip ratio of a slipping wheel (e.g., the left front wheel) reaches 15% (greater than the target slip ratio of 10%), it sends a command to the vehicle's braking system (e.g., the anti-lock braking system ABS or the electronic stability control system ESC module) to increase the braking torque of the left front wheel. This can be achieved by controlling a solenoid valve in the braking system to increase the brake fluid pressure flowing to the left front wheel brake caliper. As the braking torque increases, the slip ratio of the left front wheel begins to decrease. When the vehicle controller detects that the real-time slip ratio of the left front wheel has decreased to 8% (less than or equal to the target slip ratio of 10%), it again sends a command to the braking system to reduce the braking torque of the left front wheel, for example, by reducing the opening of the solenoid valve to reduce the brake fluid pressure, in order to avoid over-braking and maintain the slip ratio within the target range.

[0101] Part Two: The vehicle controller adjusts the front and rear axle torque distribution based on the amount of drive torque transfer.

[0102] In one possible implementation, the vehicle controller, based on the amount of drive torque transfer, increases the torque distribution ratio of the drive axle containing the coaxially attached wheel and correspondingly decreases the torque distribution ratio of the drive axle containing the slipping wheel. Based on the adjusted front and rear axle torque distribution, the vehicle controller controls the front axle electric drive source and the rear axle drive source of the vehicle to output corresponding torques.

[0103] The amount of drive torque transferred refers to the amount of drive torque originally allocated to the slipping wheel that is suppressed due to braking intervention and thus made available to the coaxial traction wheel after braking intervention. This transfer amount can be estimated or calculated in real time by monitoring parameters such as the braking torque of the slipping wheel, changes in wheel slip ratio, and the increase in drive torque of the coaxial traction wheel. For example, the braking torque can be estimated based on the braking pressure or current applied by the braking system, combined with the brake characteristic curve, and then the amount of transferred drive torque can be calculated. Another method is to determine this by comparing the decrease in drive torque of the slipping wheel before and after braking with the increase in drive torque of the coaxial traction wheel. The torque distribution ratio of the drive axle containing the traction wheel on the coaxial side refers to the proportion of torque in the total vehicle drive torque allocated to the drive axle containing the traction wheel. Increasing this torque distribution ratio aims to fully utilize the road adhesion of the traction wheel, which can be achieved by issuing a higher torque demand command to the drive source of that drive axle. The torque distribution ratio of the drive axle containing the slipping wheel refers to the proportion of torque in the total vehicle drive torque allocated to the drive axle containing the slipping wheel. The purpose of reducing the torque distribution ratio is to avoid providing excessive drive torque to the slipping wheels, thereby suppressing the exacerbation of slippage and providing more torque distribution space for the wheels with coaxial adhesion. This can be achieved by issuing a lower torque demand command to the drive source of the drive axle. The adjusted front-to-rear axle torque distribution refers to the recalculation and determination of the respective share of drive torque that the front and rear axles should bear based on the amount of drive torque transfer. This distribution result reflects the optimal torque distribution strategy under the current road adhesion conditions and the vehicle's extrication needs. Controlling the output torque of the front axle electric drive source and the vehicle's rear axle drive source means sending specific torque commands to the vehicle's front axle electric drive source and rear axle drive source based on the adjusted front-to-rear axle torque distribution result. The front axle electric drive source will output the corresponding electromagnetic torque according to the command and transmit it to the front wheels through the transmission system. The rear axle drive source will also output the corresponding mechanical or electromagnetic torque according to the command and transmit it to the rear wheels through the transmission system.

[0104] The above implementation provides torque distribution adjustment rules that match actual torque transfer requirements. This not only ensures sufficient torque distribution to the drive axle where the attached wheels are located, preventing insufficient vehicle driving force and thus preventing slippage caused by unreasonable torque distribution exceeding the road surface adhesion capacity of the attached wheels, but also fully utilizes the adhesion of each wheel to improve the vehicle's ability to get out of trouble.

[0105] To provide a clearer explanation of the above embodiments, the following describes the method in which, based on the amount of transfer of the driving torque, the torque distribution ratio of the drive axle containing the coaxially attached wheel is increased, and the torque distribution ratio of the drive axle containing the slipping wheel is correspondingly decreased.

[0106] In one possible implementation, the vehicle controller determines the increase in the torque distribution ratio of the drive axle containing the coaxially attached wheel based on the amount of drive torque transfer and the real-time adhesion of the wheel on the coaxially attached side. The vehicle controller increases the torque distribution ratio of the drive axle containing the coaxially attached wheel by the increase, and decreases the torque distribution ratio of the drive axle containing the slipping wheel by a corresponding decrease, the decrease being equal to the increase.

[0107] The method involves determining the increase in torque distribution ratio of the drive axle containing the coaxially attached wheel based on the amount of driving torque transfer and the real-time adhesion force of the wheel on the coaxial side. The aim is to calculate how much the torque distribution of the drive axle containing the coaxially attached wheel should increase during torque transfer. The core principle is to comprehensively consider the actual amount of torque to be transferred and the actual ground adhesion force that the attached wheel can withstand, ensuring that the increased torque meets the requirements for getting out of trouble without exceeding the limits of the attached wheel and avoiding secondary slippage. In some embodiments, the vehicle controller acquires the amount of driving torque transfer caused by braking intervention, which is typically calculated by the braking system or traction control system. The vehicle controller obtains dynamic information about the vehicle through wheel speed sensors, acceleration sensors, suspension sensors, etc., and combines this with a road surface friction coefficient estimation model to estimate the current adhesion force of the coaxially attached wheel in real time. The vehicle controller inputs these two parameters into a preset control algorithm, which determines a reasonable increase in torque distribution ratio based on the relationship between the two parameters. Alternatively, this can be achieved using a lookup table method or fuzzy control. One or more lookup tables are pre-stored in the vehicle controller. These lookup tables preset corresponding torque distribution ratio increases based on different drive torque transfer amounts and real-time adhesion ranges. In actual operation, the vehicle controller acquires the drive torque transfer amount and real-time adhesion in real time, and then quickly determines the required torque distribution ratio increase through table lookup or fuzzy logic reasoning. Increasing the torque distribution ratio of the drive axle containing the wheel on the coaxial side of the wheel with the specified increase is based on the increase determined in the previous step. The actual adjustment of the torque output of the drive axle on the coaxial side of the wheel with the specified increase aims to effectively distribute the drive torque transferred due to wheel slippage braking to the wheel with good adhesion, thereby improving the vehicle's driving capability and helping the vehicle get out of trouble. After determining the increase, the vehicle controller can send a command to the front axle electric drive source or the rear axle drive source (depending on the drive axle containing the wheel on the coaxial side of the wheel with the specified increase), requesting it to output additional torque corresponding to the increase on top of the original torque distribution. This is usually achieved by adjusting parameters such as the current and voltage of the drive motor or the engine throttle opening and fuel injection quantity. Alternatively, it can be achieved through a torque manager. Upon receiving the increase, the torque manager recalculates the target torque for the drive axle and coordinates the output of the new target torque from the drive source on that axle. The torque distribution ratio of the drive axle containing the slipping wheel is reduced by a corresponding decrease, simultaneously with the increase in the torque distribution ratio on the traction side. The aim is to maintain the balance of the vehicle's total drive torque while transferring drive torque from the slipping wheel to the traction wheel, avoiding sudden changes in total torque due to torque distribution adjustments, thereby maintaining vehicle stability and control accuracy. The corresponding decrease is equal to the increase, ensuring a "conservative" transfer of torque.While increasing the torque distribution ratio of the attached drive axle, the vehicle controller can send a command to the drive source of the drive axle containing the slipping wheel, requesting it to reduce its torque output by an amount equal to the original torque distribution. This is also achieved by adjusting the control parameters of the drive motor or the engine. Alternatively, when recalculating the target torque for the attached drive axle, the vehicle controller will simultaneously calculate the new target torque for the drive axle containing the slipping wheel. Since the reduction is equal to the increase, this means the torque output of the drive axle containing the slipping wheel will decrease accordingly to ensure overall torque balance.

[0108] Through the above implementation method, by determining the increase amount based on the transfer amount of driving torque and the real-time adhesion force of the wheel on the coaxial side, the increased torque can fully utilize the adhesion force provided by the attached road surface to meet the driving force required for the vehicle to get out of trouble, while avoiding excessive torque increase that could cause the wheel on the attached side to slip again. At the same time, by reducing the torque distribution ratio of the drive axle where the slipping wheel is located by a corresponding decrease equal to the increase amount, the balance of the total driving torque of the vehicle is ensured, avoiding sudden changes or insufficient total torque during torque adjustment, and maintaining the stability of vehicle driving.

[0109] To provide a clearer explanation of the above embodiments, the following describes how the increase in the torque distribution ratio of the drive axle containing the coaxially attached wheel is determined based on the amount of the transfer of the driving torque and the real-time adhesion of the wheel on the coaxially attached side.

[0110] In one possible implementation, the vehicle controller determines the adhesion margin of the wheel on the coaxially attached side based on the difference between the real-time adhesion force of the wheel on the coaxially attached side and the currently allocated drive torque of the wheel on the coaxially attached side. If the amount of drive torque transferred is less than or equal to the adhesion margin, the vehicle controller determines this increase as the amount of drive torque transferred. If the amount of drive torque transferred is greater than the adhesion margin, the vehicle controller determines this increase as the adhesion margin.

[0111] Determining the adhesion margin of the wheel on the coaxial side refers to calculating the maximum additional driving torque that the wheel can withstand under current road conditions, beyond the already allocated driving torque. Real-time adhesion can be estimated based on parameters such as the vehicle's vertical load and the road surface friction coefficient. For example, the vertical load can be obtained from the vehicle's suspension sensors or acceleration sensors, while the road surface friction coefficient can be estimated in real-time based on data from wheel speed sensors, acceleration sensors, and steering angle sensors, combined with the vehicle's dynamics model. Alternatively, real-time adhesion can be calculated using a tire model, comprehensively considering parameters such as the vehicle's longitudinal acceleration, lateral acceleration, and wheel slip ratio. The currently allocated driving torque of the wheel on the coaxial side can be directly obtained from the vehicle's powertrain controller (e.g., engine controller or motor controller), which outputs torque commands to each wheel in real-time. Alternatively, it can be obtained by monitoring the actual output torque sensor data of the wheel, or calculated inversely using parameters such as the drive motor or engine speed and current combined with the transmission ratio. The adhesion margin is determined by subtracting the currently allocated driving torque from the real-time adhesion. When the amount of driving torque transferred is less than or equal to the adhesion margin, the increase is determined as the amount of driving torque transferred. This means that when the amount of torque that the slipping wheel needs to transfer is within the tolerance range of the attached wheel, all the transfer amount will be allocated to the attached wheel. This can be achieved by setting conditional judgment logic in the vehicle controller. When the condition is met, the calculated amount of driving torque transferred is directly assigned to the increase variable used to adjust the torque distribution ratio. When the amount of driving torque transferred is greater than the adhesion margin, the increase is determined as the adhesion margin. This means that when the amount of torque that the slipping wheel needs to transfer exceeds the tolerance capacity of the attached wheel, the vehicle controller will allocate the maximum additional torque that the attached wheel can withstand (i.e., the adhesion margin) to it. This can also be achieved by setting conditional judgment logic in the vehicle controller. When the condition is met, the calculated adhesion margin is directly assigned to the increase variable used to adjust the torque distribution ratio.

[0112] Through the above implementation method, the increase in driving torque can be dynamically adjusted according to the actual adhesion capability of the wheel on the coaxial side. This avoids the risk of the wheel slipping due to the torque allocated to the attached wheel exceeding its adhesion limit during torque transfer. Therefore, the above implementation method makes the transfer of driving torque reliable and efficient, enabling the vehicle to continuously obtain maximum available driving force under slipping conditions, improving the vehicle's ability to get out of trouble and driving stability, while avoiding secondary slippage caused by improper torque distribution.

[0113] For example, the vehicle controller continuously acquires information such as wheel speed, longitudinal acceleration, lateral acceleration, and steering angle of each wheel, and combines this information with a preset tire model and road friction coefficient estimation algorithm to calculate the real-time adhesion force of the wheel on the coaxial side. Simultaneously, the vehicle controller obtains the driving torque currently allocated to the wheel on the coaxial side from the torque output commands of the front axle electric drive source and the rear axle drive source. For instance, if the right front wheel slips while the left front wheel remains taut, the vehicle controller calculates the real-time adhesion force of the left front wheel and obtains the current driving torque allocated to it. If the real-time adhesion force of the left front wheel is 2000 Nm and the currently allocated driving torque is 800 Nm, then the remaining adhesion force of the left front wheel is 1200 Nm. At this point, if the amount of drive torque that needs to be transferred to the right front wheel due to braking intervention is 1000 Nm, since 1000 Nm is less than 1200 Nm, the vehicle controller determines the increase in the front axle torque distribution ratio to be 1000 Nm, so that all 1000 Nm of drive torque is transferred to the left front wheel. If the amount of drive torque that needs to be transferred to the right front wheel is 1500 Nm, since 1500 Nm is greater than 1200 Nm, the vehicle controller limits the increase in the front axle torque distribution ratio to 1200 Nm to prevent the left front wheel from slipping due to torque overload.

[0114] Optionally, after step 304, the following steps can also be performed.

[0115] In one possible implementation, the vehicle controller monitors the wheel speed differences between multiple wheels of the vehicle and the relative wheel speed differences between the rear wheels. When the wheel speed differences recover to below a first exit threshold and the relative wheel speed differences between the rear wheels recover to below a second exit threshold, the vehicle controller starts timing. When the timing duration reaches a second timing duration threshold, the vehicle controller switches the front axle electric drive source from the unrestricted state back to the torque-restricted state.

[0116] The monitoring of wheel speed differences between multiple wheels and the relative wheel speed difference of the rear wheels aims to assess the slippage state of the vehicle's wheels in real time. Wheel speed difference typically refers to the difference between the maximum and minimum wheel speeds of all wheels, or the difference between each wheel speed and the vehicle's reference speed (such as the speed calculated by an inertial measurement unit or GPS), used to comprehensively determine the overall degree of vehicle slippage. The relative wheel speed difference of the rear wheels focuses more on the slippage of the rear axle wheels, such as the wheel speed difference between the left and right rear wheels, or the difference between the rear wheel speed and the vehicle's reference speed. This is specifically useful for determining whether the rear wheels have gained traction. Monitoring the relative wheel speed difference of the rear wheels involves real-time acquisition of wheel speed signals from each wheel using the vehicle's wheel speed sensors, which are then calculated by the vehicle controller. For example, the wheel speed difference can be calculated as the difference between the maximum and minimum wheel speeds of all wheels, or as the maximum absolute value of the difference between each wheel speed and the vehicle's reference speed. The relative wheel speed difference of the rear wheels can be calculated as the absolute value of the difference between the left and right rear wheel speeds. In addition, wheel speed information of each wheel can be obtained through the vehicle's CAN bus, and combined with data from the vehicle's longitudinal acceleration sensor, lateral acceleration sensor and yaw rate sensor, a more accurate vehicle reference speed can be estimated through a fusion algorithm, and then the slip ratio of each wheel can be calculated. Based on the slip ratio, the wheel speed difference and the relative wheel speed difference of the rear wheels can be calculated.

[0117] When the wheel speed difference recovers to below the first exit threshold and the rear wheel relative wheel speed difference recovers to below the second exit threshold, it indicates that the vehicle has escaped the slippage state. Once the vehicle is out of trouble, the wheels regain normal adhesion to the road surface, and the degree of wheel slippage will significantly decrease, manifested as a reduction in the wheel speed difference and the rear wheel relative wheel speed difference. Setting the first and second exit thresholds is to define the slippage range of "normal" or "out of trouble," avoiding misjudgments due to minor fluctuations. Meeting both conditions simultaneously improves the accuracy and robustness of the judgment. The rear wheel relative wheel speed difference is continuously monitored and calculated, and compared with the pre-calibrated first and second exit thresholds. The first and second exit thresholds can be empirically set based on factors such as vehicle type, tire characteristics, and road conditions, or optimized through experimental data. Furthermore, the first and second exit thresholds can also be dynamically adjusted, for example, adaptively adjusted based on the vehicle's current speed, driving mode (such as Sport mode, Snow mode), or estimated road friction coefficient, to better adapt to different driving environments and ensure accurate judgment of the out-of-trouble state under various conditions. After the conditions for escaping entrapment are met, the vehicle controller begins timing, aiming to introduce continuous verification over time. This avoids misjudgments caused by instantaneous changes in road conditions or brief fluctuations in sensor signals, ensuring that the vehicle is indeed stably in an entrapment state, rather than experiencing a brief, unstable recovery. The vehicle controller can integrate a timing function; when both the wheel speed difference and the rear wheel relative wheel speed difference meet the exit conditions, an internal timer is started to accumulate time. Timing can also be implemented through software logic; for example, within each control cycle, a counter increments if the exit conditions are continuously met. If the conditions are not met, the counter is reset to zero. When the counter reaches a preset value, the required timing duration is considered met. A second timing threshold is set, requiring the vehicle to maintain this state for a certain period after meeting the entrapment conditions before final confirmation of entrapment. This further enhances the reliability of the judgment, preventing premature exit from the intelligent entrapment mode due to a brief recovery of traction, which could cause the vehicle to slip again. The accumulated time of the timer is compared with the preset second timing threshold. The second timing threshold can be set empirically, for example, from 0.5 to 2 seconds, to balance response speed and judgment accuracy. It can also be dynamically adjusted based on vehicle speed, road surface adhesion coefficient, etc. For example, at high speeds, a shorter response time may be needed, while at low speeds or in complex road conditions, a longer duration may be required to ensure stability. Once it is confirmed that the vehicle has stably escaped the entrapment, the front axle electric drive source no longer needs to output torque independently in an unrestricted state; at this point, the front axle electric drive source is switched from unrestricted to torque-limited mode.Switching back to torque-limited mode, i.e., restoring the engine-constrained mode, reduces energy consumption, minimizes unnecessary system losses, and allows the vehicle to return to its original power mode, meeting the economic and stability requirements of normal vehicle operation. Upon receiving the intelligent escape mode exit command, the vehicle controller executes a series of operations. For example, it re-engages the first clutch between the engine and the front axle electric drive source and may adjust the engine's torque output strategy, causing the front axle electric drive source to be constrained by the engine again. This can also be achieved through switching control strategies. When the exit conditions are met, the vehicle controller switches from "intelligent escape mode" back to "normal driving mode" or "energy-saving mode." In "normal driving mode" or "energy-saving mode," the torque output logic of the front axle electric drive source will automatically follow the torque-limited state constraints, for example, by adjusting the operating parameters of the motor controller or the clutch engagement state.

[0118] By employing two parameters—wheel speed difference and rear wheel relative wheel speed difference—as the basis for judgment, the current slip and adhesion state of the wheels can be more accurately reflected, indicating whether the vehicle has truly overcome slippage and completed the escape. This method is more accurate than using only a single parameter and avoids misjudgments. Timing is only initiated when the wheel speed difference recovers to below the first exit threshold and the rear wheel relative wheel speed difference also recovers to below the second exit threshold. Requiring both conditions to be met simultaneously before entering the judgment process avoids erroneous exits caused by only one condition being met, ensuring that the slippage state is truly eliminated before exiting the escape intervention mode. Adding a timing duration judgment step, where the switching operation is only performed if the state continuously meets the exit conditions for a set duration, avoids erroneous switching caused by brief fluctuations in wheel speed difference during vehicle operation, ensuring the stability of the vehicle's operating state. Only when the state remains consistently stable within the normal range is the escape confirmed as complete. Once the vehicle is confirmed to be free from trouble, switching the front axle electric drive source from the unrestricted state back to the original torque-restricted state allows the power system to return to its original operating mode in a timely manner. This avoids the extra energy consumption caused by the front axle electric drive source maintaining an unrestricted independent operating state for a long time, and also reduces unnecessary wear and tear on the power system, meeting the power operation requirements for normal vehicle operation.

[0119] To provide a clearer explanation of the technical solutions provided in the embodiments of this application, the following is combined with... Figure 4 The technical solutions provided in the embodiments of this application will be described.

[0120] See Figure 4When the accelerator pedal opening exceeds a threshold, the vehicle speed exceeds a threshold, the front axle electric drive unit is in a torque-limited state (series or split mode), at least one front wheel is in a gripping state, at least one rear wheel is in a slipping state, and this condition characteristic continuously exceeds a first timing duration threshold, the slipping condition is determined to be a recoverable condition. Upon determining that the slipping condition is recoverable, the vehicle controller switches the front axle electric drive unit from a torque-limited state to an unlimited state, allowing the front and rear axle electric drive units to jointly provide drive torque; that is, activating the intelligent recovery mode and switching the vehicle to electric four-wheel drive mode. The torque-limited state refers to the front axle electric drive unit's torque output being constrained by the engine; the unlimited state refers to the front axle electric drive unit independently outputting torque after decoupling from the engine. This switching includes disconnecting the power transmission path between the engine and the front axle electric drive unit, and engaging the drive path from the front axle electric drive unit to the front wheels. The system determines whether the current gear of the front axle transmission is the target gear. If not, it switches the front axle transmission to the target gear, which provides the front wheels with a higher wheel-side torque output than the current gear. If so, it maintains the current gear. The vehicle controller applies braking intervention to the slipping wheel, generating braking torque opposite to the direction of the driving torque to change the torque distribution between the slipping wheel and the wheel on the same axle, ensuring that the driving torque of the slipping wheel is at least partially transferred to the wheel on the same axle. Based on the amount of driving torque transfer, the front and rear axle torque distribution is adjusted. The vehicle controller continuously monitors the wheel speed difference of multiple wheels and the relative wheel speed difference of the rear wheels. When the wheel speed difference recovers to less than the first exit threshold and the relative wheel speed difference of the rear wheels recovers to less than the second exit threshold, and these conditions are continuously met for a second timing duration threshold, the front axle electric drive source is switched from an unrestricted state to a torque-restricted state, exiting the intelligent traction control mode and reverting to the normal power mode (basic traction control mode).

[0121] Figure 5 This is a schematic diagram of the structure of a vehicle control device provided in an embodiment of this application. See also... Figure 5 The device includes: The slippage condition determination module 501 is used to determine the slippage condition of the vehicle when the front axle electric drive source of the vehicle is in a torque-limited state and the vehicle slips. The torque-limited state is the state in which the torque output of the front axle electric drive source is constrained by the engine.

[0122] The switching module 502 is used to switch the front axle electric drive source of the vehicle from a torque-limited state to an unlimited state when the slippage condition is a condition that can get out of trouble, so that the front axle electric drive source and the rear axle drive source of the vehicle jointly provide driving torque. The unlimited state is the state in which the front axle electric drive source outputs torque independently after being decoupled from the engine.

[0123] The intervention control module 503 is used to apply braking intervention to the slipping wheel of the vehicle when the front axle electric drive source is in the unrestricted state, and adjust the front and rear axle torque distribution based on the braking intervention to transfer the drive torque from the slipping wheel to the wheel on the coaxial attached side.

[0124] It should be noted that the vehicle control device provided in the above embodiments is only illustrated by the division of the above functional modules when controlling the vehicle. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device can be divided into different functional modules to complete all or part of the functions described above. In addition, the vehicle control device and the vehicle control method embodiments provided in the above embodiments belong to the same concept, and the specific implementation process can be found in the method embodiments, which will not be repeated here.

[0125] This application also provides a vehicle. Figure 6 This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application.

[0126] Typically, vehicle 600 includes one or more processors 601 and one or more memories 602.

[0127] Processor 601 may include one or more processing cores, such as a quad-core processor, a hexa-core processor, etc. Processor 601 may be implemented using at least one hardware form selected from DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). Processor 601 may also include a main processor and a coprocessor. The main processor, also known as a CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, processor 601 may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, processor 601 may also include an AI (Artificial Intelligence) processor, which is used to handle computational operations related to machine learning.

[0128] The memory 602 may include one or more computer-readable storage media, which may be non-transitory. The memory 602 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In some embodiments, the non-transitory computer-readable storage media in the memory 602 are used to store at least one computer program, which is executed by the processor 601 to implement the vehicle control method provided in the method embodiments of this application.

[0129] Those skilled in the art will understand that Figure 6 The structure shown does not constitute a limitation on vehicle 600 and may include more or fewer components than shown, or combine certain components, or use different component arrangements.

[0130] In addition, the device provided in the embodiments of this application may specifically be a chip, component or module. The chip may include a connected processor and a memory. The memory is used to store instructions. When the processor calls and executes the instructions, the chip can execute a vehicle control method provided in the above embodiments.

[0131] This embodiment also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer, the computer executes the above-described method steps to implement a vehicle control method provided in the above embodiment.

[0132] This embodiment also provides a computer program product that, when run on a computer, causes the computer to perform the aforementioned steps to implement a vehicle control method provided in the above embodiment.

[0133] In this embodiment, the device, computer-readable storage medium, computer program product, or chip are all used to execute the corresponding methods provided above. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0134] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0135] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0136] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for controlling a vehicle, characterized in that, The method includes: When the front axle electric drive source of the vehicle is in a torque-limited state and the vehicle slips, the slipping condition of the vehicle is determined. The torque-limited state is the state in which the torque output of the front axle electric drive source is constrained by the engine. When the slippage condition is a condition that can get out of trouble, the front axle electric drive source of the vehicle is switched from a torque-limited state to an unlimited state, so that the front axle electric drive source and the rear axle drive source of the vehicle jointly provide driving torque. The unlimited state is the state in which the front axle electric drive source outputs torque independently after being decoupled from the engine. When the front axle electric drive source is in the unrestricted state, braking intervention is applied to the slipping wheel of the vehicle, and the front and rear axle torque distribution is adjusted based on the braking intervention to transfer the drive torque from the slipping wheel to the wheel on the coaxial attached side.

2. The method according to claim 1, characterized in that, Determining the vehicle's slippage condition includes: Based on the deviation between the wheel speeds of multiple wheels of the vehicle and the vehicle speed, the slip state of each wheel is determined, and the slip state includes the adhesion state and the slipping state. If at least one front wheel among the plurality of wheels is in an traction state and at least one rear wheel among the plurality of wheels is in a slipping state, then the slipping condition is determined to be the escapable condition. If all front wheels are in a slipping state, the slipping condition is determined to be either an unavoidable situation or a reversing situation.

3. The method according to claim 2, characterized in that, When at least one front wheel among the plurality of wheels is in an traction state and at least one rear wheel among the plurality of wheels is in a slipping state, determining the slipping condition as the escapable condition includes: Timing begins when at least one front wheel is in a state of traction and at least one rear wheel is in a state of slippage. If the duration of the timing exceeds the first timing duration threshold, and the slip state of at least one front wheel remains in the attached state, and the slip state of at least one rear wheel remains in the slipping state, then the slipping condition is determined to be the escapable condition.

4. The method according to claim 1, characterized in that, Switching the front axle electric drive source of the vehicle from a torque-limited state to an unlimited state includes: Disconnect the power transmission path between the vehicle's engine and the front axle electric drive source to decouple the front axle electric drive source from the engine; The drive path from the front axle electric drive source to the front wheels is engaged so that the front axle electric drive source can independently drive the front wheels in the unrestricted state.

5. The method according to claim 4, characterized in that, Disconnecting the power transmission path between the vehicle's engine and the front axle electric drive source includes: Control the engine to stop outputting torque; When the engine stops outputting torque, the first clutch disposed between the engine and the front axle electric drive source is released to disconnect the power transmission path between the engine and the front axle electric drive source.

6. The method according to claim 4, characterized in that, The drive path connecting the front axle electric drive source to the front wheels includes: Control the front axle electric drive source to enter the torque output preparation state; After the front axle electric drive source enters the torque output preparation state, the second clutch disposed between the front axle electric drive source and the front wheel is closed to engage the drive path between the front axle electric drive source and the front wheel.

7. The method according to claim 1, characterized in that, The step of applying braking intervention to the slipping wheels of the vehicle and adjusting the front and rear axle torque distribution based on the braking intervention includes: Apply braking intervention to the slipping wheel, the braking intervention generating a braking torque opposite to the direction of the driving torque on the slipping wheel, so as to change the torque distribution relationship between the slipping wheel and the wheel on the coaxial side, so that the driving torque of the slipping wheel is at least partially transferred to the wheel on the coaxial side. The front and rear axle torque distribution is adjusted based on the amount of drive torque transferred.

8. The method according to claim 7, characterized in that, The braking intervention applied to the slipping wheel includes: Obtain the real-time slip rate of the slipping wheel; If the real-time slip ratio is greater than the target slip ratio, increase the braking torque corresponding to the slipping wheel; If the real-time slip ratio is less than or equal to the target slip ratio, the braking torque corresponding to the slipping wheel is reduced.

9. The method according to claim 7, characterized in that, Adjusting the front and rear axle torque distribution based on the amount of drive torque transfer includes: Based on the amount of driving torque transfer, the torque distribution ratio of the drive axle containing the coaxially attached wheel is increased, and the torque distribution ratio of the drive axle containing the slipping wheel is correspondingly decreased. Based on the adjusted front and rear axle torque distribution, the front axle electric drive source and the rear axle drive source of the vehicle are controlled to output corresponding torques.

10. The method according to claim 9, characterized in that, The method of increasing the torque distribution ratio of the drive axle containing the coaxially attached wheel and correspondingly decreasing the torque distribution ratio of the drive axle containing the slipping wheel, based on the transfer amount of the driving torque, includes: Based on the amount of the transfer of the driving torque and the real-time adhesion of the wheel on the coaxial side, the increase in the torque distribution ratio of the drive axle where the wheel on the coaxial side is located is determined. The torque distribution ratio of the drive axle containing the coaxially attached wheel is increased by the increase amount, and the torque distribution ratio of the drive axle containing the slipping wheel is decreased by a corresponding decrease amount, wherein the corresponding decrease amount is equal to the increase amount.

11. The method according to claim 1, characterized in that, After applying braking intervention to the slipping wheels of the vehicle and adjusting the front and rear axle torque distribution based on the braking intervention, the method further includes: Monitor the wheel speed difference between multiple wheels of the vehicle and the relative wheel speed difference between the rear wheels; Timing begins when the wheel speed difference recovers to less than the first exit threshold and the relative wheel speed difference of the rear wheels recovers to less than the second exit threshold. When the timing duration reaches the second timing duration threshold, the front axle electric drive source is switched from the unrestricted state back to the torque-restricted state.

12. The method according to claim 1, characterized in that, The method further includes: Obtain the remaining battery power of the vehicle; The remaining battery power is compared with a first power threshold. When the remaining battery power is lower than the first power threshold, the duration for which the front axle electric drive source remains in the unrestricted state is limited to a preset duration.

13. A vehicle, characterized in that, The vehicles include: Memory, used to store executable program code; A processor is configured to call and run the executable program code from the memory, causing the vehicle to perform the vehicle control method as described in any one of claims 1 to 12.

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