Vehicle drive slip control method, vehicle, and storage medium

Abstract

This invention discloses a vehicle drive anti-slip control method, a vehicle, and a storage medium. The method identifies the slippage condition of the rear axle drive wheels based on the wheel speed signals of the vehicle's existing ABS system and matches a corresponding drive torque limiting strategy. For the need to escape difficult road conditions, the method is designed with logic to automatically deactivate the drive anti-slip function based on low speed and driver operation, and automatically reactivates the function during the deactivation period by monitoring the drive wheel differential rate to protect the differential. This invention effectively balances driving safety on conventional roads, escape capability in difficult road conditions, and protection of transmission components within a low-cost ABS system architecture.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology. Specifically, this invention relates to a vehicle drive anti-skid control method, a vehicle, and a storage medium. Background Technology

[0002] Currently, commercial vehicles such as light trucks are generally equipped with ABS / ESC systems to achieve anti-lock braking and driving stability control. However, when accelerating rapidly on wet or low-traction surfaces, ABS systems are difficult to prevent drive wheel slippage, which can easily lead to rear axle fishtailing and insufficient stability. While ESC systems can provide comprehensive control, their higher cost limits their widespread adoption.

[0003] To further improve vehicle driving performance, existing technologies actively reduce the output torque of the drive motor when the drive wheels slip, in order to prevent the driving force from exceeding the ground adhesion. However, this method has a significant drawback: in extreme low-traction conditions such as mud and sand where high torque is required for getting out of trouble, the system will continuously suppress torque, resulting in insufficient vehicle driving force and causing the vehicle to become unable to get out of trouble.

[0004] This invention provides a vehicle driving anti-skid control method, specifically how to achieve both driving safety on conventional roads and passability in difficult road conditions while using a low-cost ABS system architecture. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides a vehicle driving anti-skid control method, which aims to achieve both driving safety on conventional road surfaces and passability in difficult road conditions while maintaining a low-cost ABS system architecture.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a vehicle drive anti-slip control method, applied to rear-wheel drive commercial vehicles equipped with an ABS system. The method performs control based on wheel speed signals of the front axle driven wheels and rear axle drive wheels collected by the ABS system, including: Acquire the wheel speed signals of the front axle driven wheel and the rear axle drive wheel in real time from the vehicle's ABS system; Based on the wheel speed signal, the slippage condition of the rear axle drive wheel is identified, and a preset drive anti-slip and torque reduction strategy is matched according to the identified slippage condition to perform corresponding limiting operations on the rear axle drive torque. When the preset conditions for getting out of trouble are met, the traction control function is automatically turned off based on the driver's accelerator pedal operation; when the preset conditions for function recovery are met, the traction control function is automatically turned back on. When the anti-slip function is off, the differential speed of the rear axle drive wheels is calculated in real time. If the differential speed exceeds the preset differential protection threshold, the anti-slip function is automatically restarted and the corresponding torque reduction strategy is executed.

[0007] The slippage conditions of the rear axle drive wheels include single-sided slippage and double-sided slippage; the preset drive anti-slip torque reduction strategy includes a first torque reduction strategy corresponding to the single-sided slippage condition and a second torque reduction strategy corresponding to the double-sided slippage condition.

[0008] The first torque reduction strategy is as follows: when the wheel speed difference between the two rear axle drive wheels is detected to be greater than the preset single-sided slip threshold, the vehicle controller will reset the required torque of the rear axle drive to zero.

[0009] The preset single-sided slip threshold is 30 rpm; when the wheel speed difference between the two rear axle drive wheels is greater than 30 rpm, the required torque for rear axle drive is reset to zero.

[0010] The second torque reduction strategy is as follows: calculate the wheel speed difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driving wheel of the rear axle, divide the wheel speed difference into multiple slip levels, and limit the proportion of the torque required by the rear axle drive according to the slip level. The wheel speed difference is positively correlated with the torque limit range.

[0011] The proportion of rear axle drive torque required that is limited according to slippage level is specifically as follows: When the difference between the average wheel speed of the front axle driven wheel and the average wheel speed of the rear axle driven wheel is ≥121 rpm, the torque demand of the rear axle drive is limited to 0%. When the difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driven wheel of the rear axle is 101 rpm to 120 rpm, the torque demand of the rear axle drive is limited to 30%. When the difference between the average wheel speed of the front axle driven wheel and the average wheel speed of the rear axle driven wheel is 81 rpm to 100 rpm, the torque demand of the rear axle drive is limited to 50%. When the difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driven wheel of the rear axle is 51 rpm to 80 rpm, the torque demand of the rear axle drive is limited to 70%. When the difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driven wheel of the rear axle is 30 rpm to 50 rpm, the torque required for the rear axle drive is limited to 80%.

[0012] The vehicle drive anti-skid control method also includes a torque limit recovery strategy: when the difference between the average wheel speed of the front axle driven wheel and the average wheel speed of the rear axle driven wheel is ≤40rpm, the limitation on the torque required for rear axle drive is lifted.

[0013] The formula for calculating the differential speed of the rear axle drive wheels is: Difference rate = |(N)左 -N 右 )|÷(N 左 +N 右 )×100% Where, N 左 N represents the real-time wheel speed of the left drive wheel on the rear axle. 右 The real-time wheel speed of the right drive wheel of the rear axle; the preset differential protection threshold is 20%.

[0014] The present invention also provides a vehicle, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the vehicle drive anti-skid control method.

[0015] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the vehicle drive anti-skid control method described above.

[0016] The vehicle drive anti-skid control method of the present invention, while using the low-cost ABS system architecture, simultaneously achieves drive anti-skid safety control on conventional roads, ensures the ability to get out of trouble in bad road conditions, and protects the safety of key transmission components, thus achieving a balance between cost control, vehicle driving safety, and adaptability to operating conditions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the torque reduction strategy of the present invention; Figure 2 This is a schematic diagram of the multi-road verification test data for the TCS function of the 65kW model; Figure 3 This is a schematic diagram of the test data for the TCS function under extreme low-adhesion road surface verification in ECO mode of a 65kW model under no-load conditions. Figure 4 This is a schematic diagram of the test data corresponding to the wheel speed. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] The technical concept of this invention includes: Light trucks and other commercial vehicles are widely used in urban distribution, rural and urban logistics, engineering transportation, and other scenarios. Their operating conditions cover complex environments such as paved roads, unpaved roads in urban and rural areas, and muddy construction sites, placing stringent requirements on vehicle driving stability, operating condition adaptability, and overall vehicle cost control. Currently, the braking and driving stability systems of light trucks and other commercial vehicles generally adopt ABS (Anti-lock Braking System) or ESC (Electronic Stability Control System). Among them, the ABS system, with its mature technology and low supporting costs, has become the mainstream standard solution for light truck models. Its function is to prevent wheel lock-up during vehicle braking, avoid vehicle sideslip and loss of control during braking, and ensure braking safety. However, the ABS system only performs closed-loop control for braking conditions and does not have anti-slip control capabilities under driving conditions. When a vehicle accelerates rapidly on low-friction surfaces such as wet, icy, or muddy roads, the rear drive axle is prone to slippage due to the driving force exceeding the road surface adhesion limit, leading to safety hazards such as vehicle fishtailing and loss of steering control, and failing to meet the driving stability requirements under driving conditions. While the ESC system integrates full-condition control functions such as anti-lock braking, traction control, and yaw stability control, and can simultaneously solve wheel slippage and vehicle instability problems under braking and driving conditions, it requires additional hardware such as sensors and actuators, significantly increasing the complexity of the control algorithm. This results in a significantly higher overall vehicle cost compared to the ABS system. For commercial vehicles such as light trucks, where economy is the primary selection criterion, there is a significant cost barrier to large-scale promotion and application.

[0021] To address wheel slippage during driving conditions while maintaining a low-cost ABS system architecture, existing technologies have proposed a drive anti-slip control scheme based on motor torque regulation. This scheme calculates the drive wheel slip ratio by real-time acquisition of the rotational speed signals of the drive wheels and non-drive wheels. When the drive wheel slip ratio exceeds a preset safety threshold, it is determined that the drive wheels are slipping. Subsequently, the vehicle controller reduces the output torque of the drive motor, limiting the driving force of the drive wheels to not exceed the adhesion limit of the current road surface, thereby suppressing drive wheel slippage and ensuring the driving stability of the vehicle during start-up and acceleration.

[0022] However, the existing drive anti-slip control schemes mentioned above have insurmountable technical defects: their control logic adopts a control strategy of reducing torque upon slippage, which cannot distinguish the working condition attributes of drive wheel slippage and cannot adapt to the differentiated control requirements of different driving scenarios. When a vehicle is in a mud pit, deep ditch, or other adverse road conditions and needs to get out of trouble, the driver needs the drive wheels to maintain a certain amount of slippage to obtain sufficient traction and momentum to get out of trouble. However, once the existing control program detects drive wheel slippage, it immediately executes a torque reduction operation, directly resulting in insufficient vehicle driving force. Not only does it fail to get out of trouble, but the continuous reduction in torque may also cause the vehicle to get stuck in the mud pit and unable to drive out, severely limiting the passability and scenario adaptability of light trucks and other commercial vehicles on unpaved roads and in adverse working conditions. The technical solution of the present invention is as follows: In a first aspect, embodiments of the present invention provide a vehicle drive anti-slip control method, applied to a rear-wheel drive commercial vehicle equipped with an ABS system. The method performs control based on wheel speed signals of the driven wheels of the front axle and the drive wheels of the rear axle collected by the ABS system, and includes the following steps: S1. Obtain the wheel speed signals of the front axle driven wheel and the rear axle drive wheel in real time collected by the vehicle's ABS system; S2. Based on the wheel speed signal, identify the slippage condition of the rear axle drive wheel, match the preset drive anti-slip and torque reduction strategy according to the identified slippage condition, and perform corresponding limiting operations on the rear axle drive torque. S3. When the preset conditions for getting out of trouble are met, the drive anti-slip function will be automatically turned off based on the driver's accelerator pedal operation; when the preset conditions for function recovery are met, the drive anti-slip function will be automatically turned back on. S4. When the drive anti-slip function is off, the differential speed of the rear axle drive wheels is calculated in real time. If the differential speed exceeds the preset differential protection threshold, the drive anti-slip function is automatically restarted and the corresponding torque reduction strategy is executed.

[0023] Specifically, the target vehicle applicable to this embodiment of the invention is a rear-wheel-drive pure electric light truck. The vehicle is equipped with a standard ABS system, eliminating the need for additional ESC system hardware. The vehicle control architecture is as follows: The vehicle controller communicates with the ABS system via the vehicle's CAN bus, and can acquire in real-time four wheel speed pulse signals from the ABS system: the left driven wheel of the front axle, the right driven wheel of the front axle, the left drive wheel of the rear axle, and the right drive wheel of the rear axle. The vehicle controller and the drive motor controller interact in real-time via the CAN bus. The vehicle controller can send torque commands to the drive motor controller, adjusting the output torque of the drive motor to achieve the limiting, clearing, and restoration control of the rear axle drive torque. The drive motor drives the two rear axle drive wheels, namely the left and right rear axle drive wheels, and the two front axle driven wheels, namely the left and right front axle driven wheels.

[0024] In this embodiment of the invention, the wheel speed signals of the front axle driven wheel and the rear axle driving wheel collected by the ABS system, which is standard equipment in mass-produced commercial vehicles, can be directly reused as the control basis. There is no need to add an ESC system. Without increasing the overall vehicle cost, the complete anti-slip control (TCS) function is realized. This completely solves the problems in the prior art where the ABS system cannot cover anti-slip control under driving conditions and the ESC system hardware cost is too high to be widely used in economic light trucks and other commercial vehicles. This greatly improves the mass production adaptability and economy of the solution.

[0025] In this embodiment of the invention, the slippage condition of the rear axle drive wheels is identified by wheel speed signals, and a corresponding anti-slip and torque reduction strategy is matched to execute differentiated torque limiting operations. This allows for torque control based on different degrees of drive wheel slippage, effectively suppressing excessive drive wheel slippage during rapid acceleration on low-friction surfaces such as wet, snowy, and muddy roads. It fundamentally avoids vehicle instability phenomena such as rear axle slippage, fishtailing, and sideslipping, significantly improving the vehicle's driving stability and handling safety under various road surface conditions such as wet cement, wet asphalt, and low-friction basalt, including starting, acceleration, steering, and lane changing. Real vehicle testing has verified that this solution can quickly and effectively suppress tire slippage under various low-friction road surface conditions, ensuring vehicle body stability and directional controllability.

[0026] In this embodiment of the invention, an automatic activation and deactivation logic for the drive anti-slip function under traction conditions is configured. This logic can effectively identify severe driving conditions such as vehicle traction in mud pits. When the preset traction triggering conditions are met, the drive anti-slip function is automatically deactivated based on the driver's accelerator pedal operation. This completely avoids the technical defects of insufficient vehicle driving force and inability to escape traction caused by the single closed-loop control logic of slippage leading to torque reduction in the prior art. It ensures that the vehicle can obtain sufficient traction and momentum to escape traction under severe conditions through reasonable slippage of the drive wheels. This significantly improves the passability and adaptability of light trucks and other commercial vehicles in complex road conditions such as unpaved roads and muddy construction sites.

[0027] In this embodiment of the invention, even with the anti-slip function disabled, the differential speed of the rear axle drive wheels can still be monitored in real time. When the differential speed exceeds a preset differential protection threshold, the anti-slip function is automatically reactivated and a corresponding torque reduction strategy is executed, forming a complete safety protection closed loop. This design not only ensures the vehicle's passability under difficult conditions but also effectively avoids the problem of overload damage to the planetary gears of the rear axle differential caused by excessive wheel speed difference between the two sides of the drive wheels during the escape process. It balances adaptability to extreme working conditions with the service life of key transmission components, significantly improving the overall reliability and durability of the vehicle.

[0028] In this embodiment of the invention, in step S1 above, after the vehicle is powered on and started, the vehicle controller defaults to activating the drive anti-slip control function and acquires the real-time wheel speed signals of the four wheels collected by the ABS system via the CAN bus. Then, in step S2, based on the acquired wheel speed signals, the vehicle controller calculates two important judgment parameters to identify the slippage condition of the rear axle drive wheels and matches a preset drive anti-slip torque reduction strategy according to the identified slippage condition. Specifically, the slippage condition of the rear axle drive wheels includes single-sided slippage and double-sided slippage; the preset drive anti-slip torque reduction strategy includes a first torque reduction strategy corresponding to the single-sided slippage condition and a second torque reduction strategy corresponding to the double-sided slippage condition.

[0029] The first torque reduction strategy is as follows: when the wheel speed difference between the two rear axle drive wheels is detected to be greater than the preset single-sided slip threshold, the vehicle controller will reset the required torque for the rear axle drive to zero.

[0030] In this embodiment of the invention, the preset single-sided slip threshold is 30 rpm; when the wheel speed difference ΔN between the two rear axle drive wheels... 单 When the speed exceeds 30 rpm, a torque reset operation is triggered, resetting the required torque for the rear axle drive to zero. The wheel speed difference ΔN between the two rear axle drive wheels is... 单 The calculation formula is as follows: ΔN 单 =|(N 左后 -N 右后 )| Where, N 左后 This refers to the real-time wheel speed of the left drive wheel on the rear axle, in rpm; N 右后 This represents the real-time wheel speed of the right drive wheel on the rear axle, in rpm.

[0031] When the vehicle controller detects ΔN 单 When the preset single-sided slip threshold is exceeded, the vehicle is determined to have entered a single-sided slip condition of the rear drive axle, and the first torque reduction strategy is immediately executed: the vehicle controller sends a torque zeroing command to the drive motor controller, directly setting the required torque of the rear axle drive to 0%, and quickly suppressing excessive slippage of the single-sided drive wheel.

[0032] See the implementation results of this strategy. Figure 2 The test data for the single-wheel pressure condition shown is as follows: Under the condition of single-wheel low-friction on wet asphalt pavement, when the vehicle accelerates rapidly, the single-wheel drive wheel quickly enters a slipping state, and the speed difference between the left and right rear wheels exceeds 30 rpm. After the vehicle controller triggers the torque zeroing operation, the single-wheel slippage is effectively suppressed, the vehicle does not deviate or sideslip, and the direction is completely controllable, which completely solves the risk of vehicle loss of control when accelerating on a single-wheel low-friction pavement.

[0033] The second torque reduction strategy is as follows: calculate the wheel speed difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driving wheel of the rear axle, divide the wheel speed difference into multiple slip levels, and limit the proportion of torque required by the rear axle drive according to the slip level. The wheel speed difference is positively correlated with the torque limit.

[0034] In this embodiment of the invention, the proportion of rear axle drive torque demand is limited according to the slippage level, specifically as follows: The difference ΔN between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driving wheel of the rear axle. 双 At ≥121 rpm, the rear axle drive torque requirement is limited to 0%; The difference ΔN between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driving wheel of the rear axle. 双 When the speed is between 101 rpm and 120 rpm, the torque required for rear axle drive is limited to 30%. The difference ΔN between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driving wheel of the rear axle. 双 When the speed is between 81 rpm and 100 rpm, the torque required for rear axle drive is limited to 50%. The difference ΔN between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driving wheel of the rear axle. 双 When the speed is between 51 rpm and 80 rpm, the torque required for rear axle drive is limited to 70%. The difference ΔN between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driving wheel of the rear axle. 双 When the speed is 30rpm~50rpm, the torque required for rear axle drive is limited to 80%.

[0035] ΔN 双 ΔN is the difference between the average wheel speed of the rear axle drive wheels and the average wheel speed of the front axle driven wheels. 双 The calculation formula is as follows: ΔN 双 =(N 左后 +N 右后 ) / 2-(N 左前 +N 右前 ) / 2 Where, N 左后 This refers to the real-time wheel speed of the left drive wheel on the rear axle, in rpm; N 右后 This refers to the real-time wheel speed of the right drive wheel on the rear axle, in rpm; N 左前 This is the real-time wheel speed of the left driven wheel on the front axle, in rpm; N 右前 This is the real-time wheel speed of the right driven wheel of the front axle, in rpm; only when ΔN 双 When the value is greater than 0, the determination and subsequent control of the double-sided slippage condition are executed.

[0036] When the vehicle controller detects ΔN 双When the torque is greater than 0 and exceeds the preset double-sided slippage initiation threshold of 30 rpm, the vehicle is determined to have entered a double-sided slippage condition on the rear drive axle, and the second torque reduction strategy is executed: based on ΔN 双 The numerical value is used to divide slippage into multiple gradient levels, and a graded rear axle drive torque limit ratio is set according to the different slippage levels, where ΔN 双 The larger the value, the lower the corresponding torque limiting ratio and the stronger the torque limiting force.

[0037] like Figure 2 As shown, for typical low-adhesion working conditions such as wet cement and wet asphalt pavements with adhesion coefficients μ=0.3~0.6, a large gradient, gradually limiting torque-based slippage level classification control logic is adopted, and a corresponding torque limiting recovery strategy is set. The specific parameters are set as follows: When ΔN 双 When the speed is ≥121rpm, it is judged as severe slippage, and the torque required for rear axle drive is limited to 0%. In this wheel speed difference range, the average wheel speed of the rear axle drive wheel is much higher than that of the front axle driven wheel, and it enters a pure slipping and idling state. At this time, the drive torque is directly cleared to zero, the power input is cut off instantly, and the idling drive wheel is allowed to decelerate quickly, restore effective contact friction with the ground, and terminate severe slippage from the root.

[0038] When ΔN 双 At 101rpm~120rpm, it is determined to be severe slippage, and the torque required for rear axle drive is limited to 30%. At this time, the adhesion of the drive wheel has dropped sharply, and the drive wheel is on the verge of severe free spin. The slippage is still rapidly intensifying, but it has not yet entered a completely unstable state. The slippage trend is quickly suppressed with extremely strong torque limiting force to prevent the slippage from escalating into severe instability. At the same time, 30% of the basic drive torque is retained to balance driving stability and driving smoothness.

[0039] When ΔN 双 When the speed is between 81 rpm and 100 rpm, it is determined to be moderate slippage, and the torque required for rear axle drive is limited to 50%. At this time, the tire grip of the drive wheels drops significantly, and slippage continues to develop, but the vehicle body is completely under control. By limiting the drive torque with moderate force, the slip ratio of the drive wheels is pulled back to the optimal range of peak grip, which not only prevents slippage from worsening, but also maximizes the balance between vehicle acceleration performance and driving stability, and avoids insufficient power caused by excessive torque limitation.

[0040] When ΔN 双When the speed is between 51 rpm and 80 rpm, it is considered to be a slight slippage, and the torque required for rear axle drive is limited to 70%. At this time, the drive wheel tires can still provide maximum ground adhesion, the vehicle body is completely stable, and only the initial signs of slippage appear. By intervening in the slippage trend in advance with a very slight torque limiting force, the slip ratio is stabilized in the optimal adhesion range, preventing slippage from escalating into moderate / severe slippage. At the same time, most of the 70% drive torque is retained, which has almost no impact on the normal acceleration performance of the vehicle.

[0041] When ΔN 双 When the speed is between 30 rpm and 50 rpm, it is considered a slight slippage, and the torque required for rear axle drive is limited to 80%. As the minimum intervention threshold for drive anti-slip function, only the slightest torque constraint is applied. Extremely slight intervention is made when slippage just occurs to prevent the slippage rate from continuing to rise. At the same time, almost all of the 80% drive torque is retained, which does not affect the normal starting and acceleration of the vehicle at all. The driver cannot feel the torque limiting intervention at all.

[0042] Torque limit recovery strategy: when ΔN 双 When the speed is ≤40rpm, it is determined that the drive wheel slippage has been eliminated, and the vehicle controller releases the limitation on the torque required for the rear axle drive, and outputs the drive torque completely according to the driver's accelerator pedal opening requirement.

[0043] See the implementation effect of this embodiment. Figure 2 The test data shown for conventional low-friction surfaces is as follows: Under all operating conditions, including rapid acceleration in a straight line, rapid acceleration during 90° / 180° turns, and double lane change at 60kph, the graded torque limiting logic can quickly suppress drive wheel slippage. After the TCS function intervenes, the vehicle body posture is stable without sideslip, and the power connection has only a slight, subjectively acceptable jerk, which fully meets the stability and drivability requirements of commercial vehicles under normal driving conditions.

[0044] In this embodiment of the invention, in step S3 above, the vehicle controller monitors the vehicle's driving status and driver's operation commands in real time. When the conditions for triggering the traction-free condition are met, the vehicle is determined to have entered the traction-free condition. The preset conditions for triggering the traction-free condition include: when the driver presses the accelerator pedal to perform acceleration, the average speed of the left and right driven wheels of the front axle is less than 5 km / h, and the traction control function has been triggered. The traction control function is automatically turned off according to the driver's accelerator pedal operation. Specifically, when the driver fully releases the accelerator pedal and the accelerator pedal opening is 0, the traction control function is actively turned off.

[0045] When all the above conditions are met, the vehicle controller actively shuts down the drive anti-slip function and enters the traction control mode. In the traction control mode, the vehicle controller no longer executes the drive anti-slip torque reduction strategy, but outputs drive torque entirely according to the driver's accelerator pedal opening command, allowing the drive wheels to generate a reasonable amount of slippage, providing sufficient driving force and impulse for the vehicle to get out of trouble, and completely avoiding the defects of existing technology that cause insufficient vehicle driving force and inability to drive out of mud due to forced torque reduction.

[0046] To avoid the driving safety risks caused by prolonged disabling of the traction control function in off-road mode, the vehicle controller is equipped with three levels of automatic recovery conditions. When any of the following conditions are met, the vehicle controller will immediately and automatically reactivate the traction control function and restore the normal traction control logic: (1) After the vehicle completes the key on-off operation of power-on and power-off, the vehicle controller will activate the drive anti-slip function by default; (2) The vehicle controller detects in real time that the average speed of the left and right driven wheels of the front axle is ≥10km / h, determines that the vehicle has left the traction condition, and automatically restores the drive anti-skid function; (3) If the average speed of the left and right driven wheels of the front axle is ≥5km / h and the duration of this state is ≥15s, it is determined that the vehicle has entered a stable low-speed driving state and the drive anti-skid function is automatically restored.

[0047] In this embodiment of the invention, in step S4 above, in the traction control mode where the anti-slip function is off, the vehicle controller continuously collects the real-time wheel speed signals of the left and right drive wheels of the rear axle and calculates the rear axle differential rate δ in real time. The formula for calculating the differential rate δ of the rear axle drive wheels is: Difference rate δ=|(N 左 -N 右 )|÷(N 左 +N 右 )×100% Where, N 左 N represents the real-time wheel speed of the left drive wheel on the rear axle. 右 This represents the real-time wheel speed of the right drive wheel on the rear axle.

[0048] The magnitude of the differential rate δ directly reflects the relative speed difference between the left and right drive wheels of the rear axle. The larger the differential rate, the higher the relative speed of the planetary gears of the rear axle differential, the greater the impact load it bears, and the higher the risk of failure.

[0049] In this embodiment of the invention, the preset differential protection threshold is 20%. When the vehicle controller detects δ > 20%, it determines that the planetary gears of the rear axle differential are at risk of overload damage and immediately and automatically reactivates the drive anti-slip function. Based on the currently identified slippage condition, it executes the corresponding torque reduction strategy to quickly reduce the wheel speed difference between the two drive wheels, keeping the differential speed within a safe threshold. This strategy, while ensuring the vehicle's ability to get out of trouble, effectively avoids failures such as gear grinding and burning of the planetary gears of the rear drive axle differential due to excessive speed difference and excessive load, significantly improving the reliability and service life of the entire vehicle transmission system.

[0050] like Figure 4 As shown, when the vehicle controller drives the anti-slip function normally, under the condition of low friction on one side of a flat road, the maximum speed difference between the left and right drive wheels of the rear axle during vehicle acceleration is 3 rpm, corresponding to a maximum differential rate of only 1.2%, which is always within the 20% safety threshold, and there is no risk of overload in the differential planetary gear mechanism. like Figure 4 As shown, when one drive wheel is completely slipping and there is no drive anti-slip intervention, the speed difference between the left and right drive wheels of the rear axle can reach 394 rpm, and the corresponding differential rate can reach up to 88.3%~100%, which far exceeds the rated load range of the differential planetary gear mechanism. Irreversible damage such as tooth surface wear, planetary gear shaft deformation, and tooth breakage can occur in a short time.

[0051] like Figure 4 As shown, a single-sided slippage test was conducted. Throughout the test, the vehicle controller's anti-slip function remained normally activated. Test data and control response at three key points during the slippage process were recorded, as detailed below: 1. Slippage Initiation Point: In the initial stage of the test, the left drive wheel of the rear axle completely loses traction and is in a stationary spinning state with a real-time wheel speed of 0 rpm, while the right drive wheel of the rear axle maintains traction and is in contact with the ground with a real-time wheel speed of 43 rpm. Calculations show that the wheel speed difference between the left and right drive wheels of the rear axle is 43 rpm, and the rear axle differential rate is 100.0%. At this point, the wheel speed difference has exceeded the preset 30 rpm single-sided slippage threshold of this invention, and the vehicle controller immediately triggers the single-sided slippage torque reduction strategy, sending a command to the drive motor controller to clear the rear axle drive torque to zero.

[0052] 2. Actual Response Point of the Strategy: During the execution of the torque reduction command by the vehicle controller, the left drive wheel of the rear axle remains completely stationary and spinning freely, with a real-time wheel speed of 0 rpm, while the real-time wheel speed of the right drive wheel of the rear axle rises to 225 rpm. Calculations show that the wheel speed difference between the left and right drive wheels of the rear axle is 225 rpm, and the rear axle differential rate is 100.0%. This node is the actual effective response point of the vehicle controller's torque reduction strategy. After the torque zeroing command is executed, the slippage trend of the drive wheels is quickly suppressed, preventing further slippage that could lead to vehicle deviation, fishtailing, and instability.

[0053] 3. Maximum Slippage Point: During the test, the extreme slippage point was reached when the real-time wheel speed of the left rear axle drive wheel was 26 rpm and the real-time wheel speed of the right rear axle drive wheel was 420 rpm. Calculations showed a wheel speed difference of 394 rpm between the left and right rear axle drive wheels, with a rear axle differential rate of 88.3%. At this point, the differential rate far exceeded the preset 20% differential protection threshold of this invention, verifying the necessity of triggering the differential protection strategy of this invention. If the drive anti-slip function is off, the differential planetary gears will bear extremely high impact loads under this condition, leading to irreversible damage such as tooth surface wear and tooth breakage within a short time. However, with the drive anti-slip function of this invention on, the wheel speed difference between the two drive wheels can be quickly reduced through torque zeroing, bringing the differential rate back below the safe threshold and effectively protecting the transmission components.

[0054] like Figure 4 As shown, a 0% single-sided low-adhesion test was conducted on a flat road with no slope. The vehicle drove on a flat paved road surface. Throughout the test, the vehicle controller's anti-slip function remained normally activated. Test data and control response at three key points during vehicle acceleration were recorded, as follows: 1. Test starting point: At the initial stage of vehicle start-up from a standstill, both the left and right drive wheels of the rear axle are in good grip and the real-time wheel speed is 53 rpm. After calculation, the wheel speed difference between the left and right drive wheels of the rear axle is 0 rpm, the rear axle differential speed is 0%, there is no effective slippage, the vehicle controller does not perform torque reduction intervention, and fully responds to the driver's accelerator pedal torque demand.

[0055] 2. Actual Strategy Response Point: During vehicle acceleration, one wheel enters the low-friction zone. The real-time wheel speed of the left rear axle drive wheel is 119 rpm, and the real-time wheel speed of the right rear axle drive wheel is 122 rpm. Calculations show that the absolute value of the wheel speed difference between the left and right rear axle drive wheels is 3 rpm, and the absolute value of the rear axle differential rate is 1.2%. At this point, the wheel speed difference between the two drive wheels is far below the preset 30 rpm single-sided slip threshold of this invention, and the differential rate is far below the 20% differential protection threshold. The vehicle controller determines this as a minor fluctuation in wheel speed under normal driving conditions and does not execute torque reduction intervention, effectively avoiding false triggering of the strategy under normal driving conditions and ensuring normal vehicle acceleration performance.

[0056] 3. Maximum Acceleration Point: The peak wheel speed point during vehicle acceleration. The real-time wheel speed of the left rear axle drive wheel was 163 rpm, and the real-time wheel speed of the right rear axle drive wheel was 161 rpm. Calculations show that the wheel speed difference between the left and right rear axle drive wheels is 2 rpm, and the rear axle differential rate is 0.6%. Throughout the acceleration process, the wheel speed difference between the two drive wheels remained at an extremely low level, and the differential rate did not exceed the 20% safety threshold. The vehicle controller did not erroneously trigger intervention, there was no power interruption during vehicle acceleration, the vehicle body posture remained stable, and there was no sideslip.

[0057] Based on the above real vehicle test data, the protection threshold was set at 20%. This threshold not only provides sufficient margin for the difference in speed between the left and right wheels to help the vehicle get out of trouble and meet the slippage requirements of the extrication condition, but also allows for timely intervention when the differential speed exceeds the safe range, eliminating the risk of differential overload damage, thus balancing extrication capability and transmission system reliability.

[0058] The vehicle drive anti-skid control method of this invention has been verified through full-condition real-vehicle testing on a 65kW unloaded pure electric light truck. Figure 2 and Figure 3 As shown, the tests covered all scenarios of low-friction driving conditions, including slippery cement roads, slippery asphalt roads, slippery basalt roads, and single-wheel split-type roads. The test conditions included rapid acceleration in a straight line while stationary, rapid acceleration while turning, double lane change, acceleration after docking, and split-type braking, encompassing all driving scenarios for commercial vehicles. Test results show that this method, through software control logic optimization alone, can achieve complete drive anti-slip control functions while maintaining the existing ABS system architecture. It effectively suppresses drive wheel slippage and rear axle fishtailing during acceleration on low-friction surfaces, ensuring vehicle stability. Simultaneously, it can effectively identify traction problems, solving the problem of vehicles getting out of difficult conditions such as mud pits. It balances driving safety on conventional roads, passability in adverse conditions, and overall vehicle cost control, fully adapting to the multi-scenario and complex operating needs of light trucks and other commercial vehicles.

[0059] in, Figure 2 This diagram illustrates the multi-road surface verification test data of the TCS function for the 65kW model. Presented as a test comparison table, it shows the comparative test results of the 65kW test vehicle with the TCS function enabled and disabled on three types of low-adhesion road surfaces: wet and slippery cement road, wet and slippery asphalt road, and wet and slippery asphalt pavement. The test covers all operating conditions, including rapid acceleration in a straight line, rapid acceleration while turning at 90° / 180°, double lane change, straight-line braking, and single-wheel lane-crossing acceleration and lane change. It clearly records the vehicle's sideslip, instability, and subjective evaluation of control performance under different operating conditions.

[0060] Figure 3 This diagram illustrates the test data for the TCS function under extreme low-adhesion road surface verification in ECO mode and no-load condition for a 65kW vehicle. Presented as a test comparison table, the diagram shows the comparative test results of the 65kW test vehicle in ECO mode (Ecology, Conservation, and Optimization, also known as Economy mode) and no-load condition on a wet, slippery basalt road surface with an extreme low-adhesion coefficient. It covers test conditions such as slow acceleration, rapid acceleration, coasting, split braking, and braking, clearly recording the vehicle's sideslip, instability, and control performance evaluation at different test speeds.

[0061] Secondly, embodiments of the present invention also provide a vehicle, which is an electric commercial vehicle, comprising: a memory, a communication interface, a processor, and a computer program stored in the memory and executable on the processor. The processor, the communication interface, and the memory communicate with each other via a communication bus. When the processor executes the program, it implements the vehicle drive anti-skid control method provided in the above embodiments.

[0062] The aforementioned communication bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc.

[0063] The memory may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0064] The processor can be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

[0065] Thirdly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the vehicle drive anti-skid control method provided in the above embodiments.

[0066] According to embodiments of the present invention, the computer-readable storage medium may be a non-volatile computer-readable storage medium, such as including, but not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In the present invention, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0067] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A vehicle drive anti-skid control method, applied to rear-wheel drive commercial vehicles equipped with an ABS system, characterized in that, include: Acquire the wheel speed signals of the driven wheel of the front axle and the drive wheel of the rear axle; Based on the wheel speed signal, the slippage condition of the rear axle drive wheel is identified, and a preset drive anti-slip and torque reduction strategy is matched according to the identified slippage condition to perform corresponding limiting operations on the rear axle drive torque. When the preset conditions for getting out of trouble are met, the drive anti-slip function will be automatically turned off based on the driver's operation of the accelerator pedal. When the preset function recovery conditions are met, the anti-slip function will be automatically restarted. When the anti-slip function is off, the differential speed of the rear axle drive wheels is calculated in real time. If the differential speed exceeds the preset differential protection threshold, the anti-slip function is automatically restarted and the corresponding torque reduction strategy is executed.

2. The vehicle drive anti-skid control method according to claim 1, characterized in that, The slippage conditions of the rear axle drive wheels include single-sided slippage and double-sided slippage; the preset drive anti-slip torque reduction strategy includes a first torque reduction strategy corresponding to the single-sided slippage condition and a second torque reduction strategy corresponding to the double-sided slippage condition.

3. The vehicle drive anti-skid control method according to claim 2, characterized in that, The first torque reduction strategy is as follows: when the wheel speed difference between the two rear axle drive wheels is detected to be greater than the preset single-sided slip threshold, the vehicle controller will reset the required torque of the rear axle drive to zero.

4. The vehicle drive anti-skid control method according to claim 3, characterized in that, The preset single-sided slip threshold is 30 rpm; when the wheel speed difference between the two rear axle drive wheels is greater than 30 rpm, the required torque for rear axle drive is reset to zero.

5. The vehicle drive anti-skid control method according to claim 2, characterized in that, The second torque reduction strategy is as follows: calculate the wheel speed difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driving wheel of the rear axle, divide the wheel speed difference into multiple slip levels, and limit the proportion of the torque required by the rear axle drive according to the slip level. The wheel speed difference is positively correlated with the torque limit range.

6. The vehicle drive anti-skid control method according to claim 5, characterized in that, The proportion of rear axle drive torque required that is limited according to slippage level is specifically as follows: When the difference between the average wheel speed of the front axle driven wheel and the average wheel speed of the rear axle driven wheel is ≥121 rpm, the torque demand of the rear axle drive is limited to 0%. When the difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driven wheel of the rear axle is 101 rpm to 120 rpm, the torque demand of the rear axle drive is limited to 30%. When the difference between the average wheel speed of the front axle driven wheel and the average wheel speed of the rear axle driven wheel is 81 rpm to 100 rpm, the torque demand of the rear axle drive is limited to 50%. When the difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driven wheel of the rear axle is 51 rpm to 80 rpm, the torque demand of the rear axle drive is limited to 70%. When the difference between the average wheel speed of the driven wheel of the front axle and the average wheel speed of the driven wheel of the rear axle is 30 rpm to 50 rpm, the torque required for the rear axle drive is limited to 80%.

7. The vehicle drive anti-skid control method according to claim 6, characterized in that, It also includes a torque limit recovery strategy: when the difference between the average wheel speed of the front axle driven wheel and the average wheel speed of the rear axle driven wheel is ≤40rpm, the limit on the torque required for the rear axle drive is lifted.

8. The vehicle drive anti-skid control method according to claim 1, characterized in that, The formula for calculating the differential speed of the rear axle drive wheels is: Difference rate = |(N) 左 -N 右 )|÷(N 左 +N 右 )×100% Where, N 左 N represents the real-time wheel speed of the left drive wheel on the rear axle. 右 The real-time wheel speed of the right drive wheel of the rear axle; the preset differential protection threshold is 20%.

9. A vehicle, characterized in that, include: The device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the vehicle drive anti-skid control method as described in any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the vehicle drive anti-skid control method as described in any one of claims 1 to 8.

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