Vehicle inter-axle slip limiting method, device, storage medium and program product

Abstract

The application discloses a vehicle inter-axle limited slip method, device, storage medium and program product, relates to the technical field of vehicle control, and discloses a vehicle inter-axle limited slip method, which comprises the following steps: when a differential lock of a vehicle is locked, a target axle to be coordinated is determined, the target axle corresponds to a wheel slip amount greater than a preset threshold value or a positive gradient of the wheel slip amount greater than a preset gradient value; expected torques of each axle are acquired, and wheel end boundary values corresponding to the each axle are acquired, the expected torques of the each axle being pre-assigned wheel end torques; and a target torque of the target axle is determined according to the expected torques of the each axle and the wheel end boundary values. The application transfers the required torque of the target axle, i.e. the expected torque, to other axles with small or no sliding trend, thereby improving the passability of the vehicle.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to vehicle axle slip limiting methods, devices, storage media and program products. Background Technology

[0002] In three-axle, six-wheeled vehicles, the front axle typically has one axle and two wheels, while the rear has two axles and four wheels. Three-axle, six-wheeled vehicles or off-road vehicles often have heavy loads and large dimensions, so they are generally equipped with limited-slip differential systems. For example, they may use a TCS (Traction Control System). The TCS system works by reducing engine torque or braking the slipping wheels to maintain vehicle stability when it detects a loss of traction. However, when the vehicle is at low speeds or trying to get out of a difficult situation, the TCS system cannot control slippage and extricate the vehicle by reducing engine torque or braking the slipping wheels. Summary of the Invention

[0003] The main purpose of this application is to provide a vehicle axle slip limiting method, device, storage medium and program product, which aims to solve the technical problem that when a vehicle enters a low speed or when it is in trouble, the TCS system cannot control the slipping and getting out of trouble by reducing engine torque or braking the slipping wheels.

[0004] To achieve the above objectives, this application proposes a method for limiting inter-axle slip in vehicles, the method comprising:

[0005] When the differential lock of the vehicle is locked, the target shaft of the torque to be coordinated is determined, and the wheel slippage of the target shaft is greater than a preset threshold or the positive gradient of the wheel slippage is greater than a preset gradient value.

[0006] Obtain the desired torque of each shaft and the corresponding wheel end boundary value of each shaft, wherein the desired torque of each shaft is the pre-allocated wheel end torque;

[0007] The target torque of the target shaft is determined based on the desired torque of each shaft and the wheel end boundary value.

[0008] In one embodiment, the wheel-end boundary values ​​include wheel-end positive torque boundaries for torque distribution of each axle. The step of determining the torque of the target axle based on the desired torque of each axle and the wheel-end boundary values ​​includes:

[0009] When the desired torque of each axle of the vehicle is greater than the positive torque boundary of the wheel end for torque distribution of each axle, the target torque of the target axle for inter-axle limited slip coordination is determined according to the desired torque of each axle and the positive torque boundary.

[0010] In one embodiment, the wheel-end boundary values ​​include wheel-end negative torque boundaries for torque distribution on each axle. The step of determining the torque of the target axle based on the desired torque of each axle and the wheel-end boundary values ​​includes:

[0011] When the desired torque of each axle of the vehicle is less than the negative torque boundary of the wheel end for torque distribution of each axle, the target torque of the target axle for inter-axle limited slip coordination is determined based on the desired torque of each axle and the negative torque boundary.

[0012] In one embodiment, the step of determining the target torque of the target shaft based on the desired torque of each shaft and the wheel end boundary value includes:

[0013] Based on the relationship between the expected torque of each shaft and the wheel end boundary value, determine the shaft with limited torque request;

[0014] The target torque of the target shaft is determined based on the motor capacity gap of the shaft with limited torque request.

[0015] In one embodiment, when the vehicle is a three-axle vehicle, the step of determining the target torque of the target axle based on the motor capacity gap of the axle with the limited torque request includes:

[0016] When the shafts with limited torque requests include two other shafts besides the target shaft, determine the absolute value of the sum of the motor capacity gaps of the other two shafts, and determine the minimum value between the motor margin capacity of the target shaft and the absolute value.

[0017] The first coefficient is determined based on the magnitude of the desired torque of the target shaft;

[0018] The target torque of the target shaft is determined based on the desired torque of the target shaft, the minimum value, and the first coefficient.

[0019] In one embodiment, when the vehicle is a three-axle vehicle, the step of determining the target torque of the target axle based on the motor capacity gap of the axle with the limited torque request includes:

[0020] When the torque request of the target shaft is limited, and the torque request of one of the other two shafts is limited, a second coefficient is determined based on the expected torque magnitude of the target shaft.

[0021] The target torque of the target shaft is determined based on the desired torque of the target shaft, the motor capacity gap of the target shaft, and the second coefficient.

[0022] In one embodiment, when the vehicle is a three-axle vehicle, the step of determining the target torque of the target axle based on the motor capacity gap of the axle with the limited torque request includes:

[0023] When the torque request of only the target shaft is limited, a third coefficient is determined based on the expected torque magnitude of the target shaft;

[0024] The target torque of the target shaft is determined based on the desired torque of the target shaft, the motor capacity gap of the target shaft, and the third coefficient.

[0025] In one embodiment, when the vehicle is a three-axle vehicle, the step of determining the target torque of the target axle based on the motor capacity gap of the axle with the limited torque request includes:

[0026] When the torque request of one of the two axes other than the target axis is limited, a fourth coefficient is determined based on the expected torque magnitude of the target axis;

[0027] Determine the product of the absolute value of the motor capacity gap of the other two axes and the preset torque axis transfer coordination factor, and determine the motor margin of the target axis and the minimum value of the product;

[0028] The target torque of the target shaft is determined based on the desired torque of the target shaft, the minimum value, and the fourth coefficient.

[0029] In one embodiment, before the step of determining the product of the absolute value of the motor capacity gap of the other two axes and a preset torque shaft transfer coordination factor, the method further includes:

[0030] Determine the slip limit safety factor for each axis, wherein the slip limit safety factor is determined by the rate of change of motor slippage;

[0031] Based on the aforementioned slip-limiting safety factor, determine the slip-limiting safety factor;

[0032] Determine the effective capacity gap ratio, and determine the maximum torque fine-tuning safety factor based on the effective capacity gap ratio and the preset direction sign coefficient;

[0033] Based on the limited-slip safety factor and the maximum torque fine-tuning safety factor, the torque shaft transfer coordination factor is determined.

[0034] In one embodiment, the method includes:

[0035] When the expected torque of each axis is greater than or equal to 0, if the expected torque of any axis is less than or equal to the corresponding positive torque boundary, then the motor margin of any axis is determined based on the difference between the positive torque boundary and the expected torque of any axis.

[0036] If the desired torque of any shaft is greater than the positive torque boundary, then the motor capacity gap of any shaft is determined based on the difference between the positive torque boundary and the desired torque of any shaft.

[0037] In one embodiment, the method includes:

[0038] When the expected torque of each axis is less than 0, if the expected torque of any axis is greater than or equal to the corresponding negative torque boundary, then the motor margin of any axis is determined based on the difference between the negative torque boundary and the expected torque of any axis.

[0039] If the desired torque of any shaft is less than the negative torque boundary, then the motor capacity gap of any shaft is determined based on the difference between the negative torque boundary and the desired torque of any shaft.

[0040] In one embodiment, the step of obtaining the wheel end boundary values ​​corresponding to each shaft includes:

[0041] The pre-slip torque of any shaft is determined based on the difference between the actual torque of the current motor of any shaft and the pre-slip torque reduction of any shaft and the preset closed-loop adjustment amount.

[0042] The wheel end boundary value of any axle is determined by multiplying the difference with the preset limited-slip protection time factor.

[0043] In addition, to achieve the above objectives, this application also proposes a vehicle inter-axle slip limiting device, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the vehicle inter-axle slip limiting method as described above.

[0044] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the vehicle inter-axle limited slip method as described above.

[0045] In addition, to achieve the above objectives, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the vehicle inter-axle limited slip method described above.

[0046] One or more technical solutions proposed in this application have at least the following technical effects:

[0047] When the vehicle's differential lock is engaged, the target axle for the torque to be coordinated is determined, the desired torque of each axle is obtained, and the corresponding wheel end boundary value for each axle is also obtained. Based on the desired torque of each axle and the wheel end boundary value, the target torque of the target axle for inter-axle slip limitation is determined. By coordinating the torque of the target axle, the required torque, i.e., the desired torque, of the target axle is transferred to other axles with low or no slippage tendency. For the entire vehicle, the drive torque is adjusted to the axle with a high coefficient of adhesion, which greatly improves the vehicle's passability, enables slippage and extrication, and enhances its ability to drive under different road conditions, especially its driving performance on complex or harsh road surfaces. Attached Figure Description

[0048] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0049] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a flowchart illustrating an embodiment of the vehicle inter-axle limited slip method of this application.

[0051] Figure 2 A simplified flowchart illustrating Embodiment 1 of the vehicle inter-axle limited slip method of this application;

[0052] Figure 3 This is a flowchart illustrating Embodiment 2 of the vehicle inter-axle limited slip method of this application;

[0053] Figure 4 This is a flowchart illustrating Embodiment 3 of the vehicle inter-axle limited slip method of this application;

[0054] Figure 5 This is a flowchart illustrating Embodiment 4 of the vehicle inter-axle limited slip method of this application;

[0055] Figure 6 This is a flowchart illustrating Embodiment 5 of the vehicle inter-axle limited slip method of this application;

[0056] Figure 7 This is a flowchart illustrating Embodiment Six of the vehicle inter-axle limited slip method of this application;

[0057] Figure 8 This is a flowchart illustrating Embodiment Seven of the inter-axle limited slip method for vehicles in this application;

[0058] Figure 9This is a schematic diagram of item I of the closed-loop control of the reset torque inter-axle transfer coordination factor in the vehicle inter-axle limited slip method of this application;

[0059] Figure 10 A simplified flowchart is provided for Embodiment 7 of the vehicle inter-axle limited slip method of this application;

[0060] Figure 11 This is a flowchart illustrating Embodiment 8 of the vehicle inter-axle limited slip method of this application;

[0061] Figure 12 This is a schematic diagram of the equipment structure of the hardware operating environment involved in the vehicle axle limited slip method in the embodiments of this application.

[0062] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0063] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0064] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0065] The main solution of this application embodiment is: when the differential lock of the vehicle is locked, the target shaft of the torque to be coordinated is determined, the expected torque of each shaft is obtained, and the wheel end boundary value corresponding to each shaft is obtained; based on the expected torque of each shaft and the wheel end boundary value, the target torque of the target shaft for inter-axle slip limitation is determined.

[0066] In this embodiment, for ease of description, the following description uses the vehicle inter-axle limited slip device as the main execution subject.

[0067] This application provides a solution that, by coordinating the torque of the target shaft, transfers the required torque, i.e. the desired torque, of the target shaft to other shafts with low or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the shaft with a high coefficient of adhesion, which greatly improves the vehicle's passability, enables slippage and escape, and improves its ability to drive under different road conditions, especially its driving performance on complex or harsh roads.

[0068] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or an electronic device capable of performing the above functions, such as a vehicle inter-axle slip limiting device. For example, the vehicle inter-axle slip limiting device is a vehicle infotainment system or controller. The following uses a vehicle inter-axle slip limiting device as an example to describe this embodiment and the following embodiments.

[0069] Based on this, embodiments of this application provide a method for limiting inter-axle slip in vehicles, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the vehicle inter-axle limited slip method of this application.

[0070] In this embodiment, the vehicle inter-axle slip limiting method includes steps S10 to S30:

[0071] Step S10: When the differential lock of the vehicle is locked, the target shaft of the torque to be coordinated is determined, wherein the wheel slippage of the target shaft is greater than a preset threshold or the positive gradient of the wheel slippage is greater than a preset gradient value.

[0072] It should be noted that the target axle is the axle corresponding to the slipping wheel, and the target axle is the axle to be coordinated in the inter-axle limited slip strategy. Optionally, this application is applied to multi-axle vehicles, such as two-axle or three-axle vehicles. Optionally, when the vehicle is a three-axle vehicle, the target axle can be the front axle, the middle axle, or the rear axle.

[0073] Inter-axle limited-slip control is controlled from the drive end, achieving inter-axle slip by transferring the required drive torque. During vehicle acceleration, when the speed of one axle motor translates to a wheel-end speed exceeding the preset thresholds of two other corresponding signals, the inter-axle limited-slip control activates. This involves transferring the required torque from the slipping axle to the axle with less or no slippage among the other two axles. Moreover, this applies regardless of the presence or absence of an inter-wheel differential lock. Thus, for the entire vehicle, adjusting the drive torque to the axle with a high coefficient of friction significantly improves the vehicle's passability and its ability to operate under various road conditions, particularly its performance on complex or harsh surfaces such as mud, sand, snow, and steep slopes. As a complementary function to TCS (Traction Control System), the inter-axle limited-slip control achieves inter-axle slippage in scenarios where TCS cannot be activated, such as when an inter-wheel differential lock is present. The inter-axle limited-slip control is adaptive, autonomous, flexible, and independent of the chassis supplier. It can quickly transfer slippage from one axle to another axle with less slippage. The inter-axle limited slip strategy not only considers slippage transfer, but also the optimization problem of maximizing the transfer amount.

[0074] Optionally, when preset conditions are simultaneously met, the inter-axle limited slip function is enabled, with InterLimSlipEna = 1. The preset conditions include: the differential lock is locked; the driving mode is Sport mode or another mode requiring inter-axle limited slip; the vehicle is in drive mode; and the TCS (Traction Control System) is not activated.

[0075] It should be noted that when the inter-axle limited slip function is enabled, the wheel slip linear velocity of the target axle is determined based on the motor speed, the transmission ratio of the target axle, and the effective radius of the wheel; the wheel slip amount of the target axle is determined based on the difference between the minimum wheel slip linear velocity of the target axle and the wheel slip linear velocities of the other two axles.

[0076] For example, taking the target axle as the front axle, the calculation of wheel slippage is as follows: Front axle wheel slippage = Front axle wheel slippage linear velocity - Min(Middle axle wheel slippage linear velocity, Rear axle wheel slippage linear velocity); Conversely, front axle wheel slippage = 0; Wherein, the calculation of wheel slippage linear velocity is as follows: Wheel slippage linear velocity = Motor speed / Shaft transmission ratio * 2 * pi / 60 * Effective wheel radius.

[0077] Optionally, when a preset activation condition is met, the inter-axle slip limiting function is activated; after the inter-axle slip limiting function is activated, step S10 is executed; wherein, meeting the preset activation condition includes at least one of the following: the wheel slippage of the target axle is greater than a preset threshold and lasts for a preset duration; the positive gradient of the wheel slippage of the target axle is greater than a preset gradient value and lasts for a preset duration. The above timing must have a maximum time protection, and it must be automatically reset to zero after the condition is not met.

[0078] The front axle inter-axle limited slip function will not be activated when all of the following conditions are met: the wheel slippage on the target axle is less than a preset threshold for a preset time; and the inter-axle limited slip function is disabled. The above timing must have a maximum time protection and will be automatically reset to zero if the conditions are not met.

[0079] Step S20: Obtain the desired torque of each shaft and obtain the wheel end boundary value corresponding to each shaft, wherein the desired torque of each shaft is the pre-allocated wheel end torque.

[0080] It should be noted that the expected torque for each axle is the pre-allocated wheel-end torque. In the inter-axle limited-slip strategy, the expected torque for each axle is the torque value that each axle should ideally receive. Before torque distribution, the system calculates an ideal torque distribution scheme based on the current operating conditions and control logic. This scheme represents the desired target, but the actual distributed torque may be limited by various factors, such as motor capacity, transmission system efficiency, and wheel adhesion conditions.

[0081] Optionally, the wheel end boundary values ​​include the positive torque boundary FaMotTqAvlMax and the negative torque boundary FaMotTqAvlMin.

[0082] When the vehicle's actual gear is forward and the required torque is >0, if the inter-axle limited slip function is activated, the positive torque boundary for target axle torque distribution FaMotTqArbnMax = the positive torque boundary FaMotTqAvlMax after the inter-axle limited slip of the target axle is activated; otherwise, the positive torque boundary for target axle torque distribution = the upper boundary of the motor's own capacity.

[0083] When the vehicle's actual gear is reverse and the required torque is <0, if the inter-axle limited slip function is activated, the negative torque boundary for target axle torque distribution FaMotTqArbnMin = the negative torque boundary FaMotTqAvlMin after the inter-axle limited slip of the target axle is activated; otherwise, the negative torque boundary for target axle torque distribution = the lower boundary of the motor's own capability.

[0084] Optionally, the wheel end boundary value of any shaft is determined based on the difference between the current actual torque of the motor of any shaft and the pre-slip torque reduction amount and the preset closed-loop adjustment amount of any shaft; and based on the product of the difference and the preset limited-slip protection time factor.

[0085] Furthermore, when the inter-axis limited slip function of the target shaft is activated, the target shaft motor boundary is first lowered to the actual torque of the current motor, then the pre-slip torque reduction of the target shaft is subtracted, then the closed-loop adjustment is subtracted, and finally the result is multiplied by the limited slip protection time factor to obtain the positive torque boundary FaMotTqAvlMax after the inter-axis limited slip of the target shaft is activated. For example, the calculation formula is shown below:

[0086] FaMotTqAvlMax = (Current motor actual torque - Pre-slip torque reduction - Closed-loop adjustment) × Limited-slip protection time factor.

[0087] The front axle pre-slip torque reduction is determined by a two-dimensional lookup table based on wheel slippage and actual torque. The front axle limited-slip closed-loop adjustment is achieved using a PID (Proportional-Integral-Derivative) algorithm with a target of zero wheel slippage. The front axle limited-slip protection time factor is determined by a one-dimensional lookup table based on the activation time of the inter-axle limited-slip function. It is regulated by a PI closed-loop system within a specified time, and the boundary is narrowed by multiplying by the time factor after exceeding this time. The initial data in the data tables is preset based on simulation results and subsequently modified based on real-vehicle calibration.

[0088] Treated in the same way as the negative boundary, the final result is the negative torque boundary FaMotTqAvlMin after the front axle inter-axle limited slip activation.

[0089] Step S30: Determine the target torque of the target shaft based on the desired torque of each shaft and the wheel end boundary value.

[0090] Optionally, when the wheel end boundary value includes a positive torque boundary, and when the desired torque of each axle of the vehicle is greater than a preset torque value, the target torque of the target axle for inter-axle limited-slip coordination is determined based on the desired torque of each axle and the positive torque boundary. The preset torque value can be 0. Optionally, when the desired torque of the target axle is greater than or equal to the positive torque boundary, the target torque is determined to be the positive torque boundary; when the desired torque of the target axle is less than the positive torque boundary, the target torque is determined to be the desired torque of the target axle.

[0091] Optionally, when the wheel end boundary value includes a negative torque boundary, and when the desired torque of each axle of the vehicle is less than a preset torque value, the target torque of the target axle for inter-axle limited-slip coordination is determined based on the desired torque of each axle and the negative torque boundary. The preset torque value can be 0. Optionally, when the desired torque of the target axle is less than or equal to the negative torque boundary, the target torque is determined to be the negative torque boundary; when the desired torque of the target axle is greater than the negative torque boundary, the target torque is determined to be the desired torque of the target axle.

[0092] In an alternative embodiment, such as Figure 2 As shown, after step S30, the three-axis torque distribution ratio is converted, that is, the torque after the driver's demand within the capability range is converted into the three-axis ratio according to 100%. The calculation formula is the torque allocated to the current axis / the sum of the torques allocated to all axes. Next, a distribution filtering ratio is applied. The calculated distribution ratio is filtered using the RAMP (Ramp Control Strategy). The Ramp strategy limits the range of single-step increases and decreases; if the limit is exceeded, the execution follows the limit, otherwise the actual execution is performed. Then, the distribution ratio is converted into motor-end torque, that is, the driver's demand torque within the capability range is converted to the motor-end torque of each axis according to the distribution ratio. The calculation formula is the driver's demand torque within the capability range * distribution ratio / 100 / the transmission ratio of the corresponding axis. For safety, motor boundaries need to be limited. Finally, motor torque filtering is performed. The motor torque of each axis undergoes first-order hysteresis filtering. In torque mode, torque commands are sent to the motors for execution in conjunction with motor mode control.

[0093] In the technical solution of this embodiment, when the vehicle's differential lock is engaged, the target axle for the torque to be coordinated is determined, the desired torque of each axle is obtained, and the corresponding wheel end boundary value of each axle is obtained. Based on the desired torque of each axle and the wheel end boundary value, the target torque of the target axle for inter-axle slip limitation is determined. By coordinating the torque of the target axle, the required torque of the target axle, i.e., the desired torque, is transferred to other axles with low or no slippage tendency. For the entire vehicle, the driving torque is adjusted to the axle with a high coefficient of adhesion, which greatly improves the vehicle's passability, enables slippage and extrication, and improves its ability to drive under different road conditions, especially its driving performance on complex or harsh road surfaces.

[0094] Based on the first embodiment of this application, in the second embodiment of this application, the same or similar content as the above embodiment can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 3 Step S30 includes:

[0095] Step S31: Based on the relationship between the expected torque of each shaft and the wheel end boundary value, determine the shaft with limited torque request;

[0096] Step S32: Determine the target torque of the target shaft based on the motor capacity gap of the shaft with limited torque request.

[0097] It should be noted that the vehicle can be a two-axle vehicle, such as an off-road vehicle, in which each axle is equipped with a differential lock. The vehicle can also be a three-axle vehicle, in which all three axles can be equipped with differential locks, or the rear two axles of a three-axle vehicle can be equipped with differential locks.

[0098] Optionally, when the vehicle is a two-axle vehicle, the target axle is the axle with limited torque request. A coefficient is determined based on the expected torque of the target axle; the target torque of the target axle is determined based on the expected torque of the target axle, the motor capacity gap of the target axle, and the coefficient. The target axle torque for inter-axle limited slip coordination = expected torque of the target axle + motor capacity gap of the target axle * coefficient, where the coefficient = IF(expected torque of target axle < 0, -1, 1), and IF(condition, A, B) means that if the condition is met, A is selected; otherwise, B is selected.

[0099] Optionally, when the vehicle is a two-axle vehicle, the other axle besides the target axle is the axle with limited torque request. The absolute value of the sum of the motor capacity gaps of the other two axles is determined, and the minimum absolute value of the motor surplus capacity of the target axle is determined. A first coefficient is determined based on the magnitude of the desired torque of the target axle. The target torque of the target axle is determined based on the desired torque, the minimum value, and the first coefficient. The target torque of the target axle for inter-axle limited slip coordination = desired torque of the target axle + min(motor surplus capacity of the target axle, abs motor capacity gap of the other axle) * coefficient, where the coefficient = IF(desired torque of the target axle < 0, -1, 1). IF(condition, A, B) indicates that if the condition is met, A is selected; otherwise, B is selected.

[0100] In the technical solution of this embodiment, by calculating the target torque of the target shaft, the required torque of the target shaft, i.e. the desired torque, is transferred to other shafts with small or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the shaft with a high adhesion coefficient, which greatly improves the vehicle's passability, i.e., improves its ability to drive under different road conditions, especially its driving performance on complex or harsh roads.

[0101] Based on the first or second embodiment of this application, in the third embodiment of this application, the content that is the same as or similar to the above embodiments can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 3 Step S32 includes:

[0102] Step S321: When the shafts with limited torque requests include two other shafts besides the target shaft, determine the absolute value of the sum of the motor capacity gaps of the other two shafts, and determine the minimum value between the motor surplus capacity of the target shaft and the absolute value.

[0103] Step S322: Determine the first coefficient based on the magnitude of the desired torque of the target shaft;

[0104] Step S323: Determine the target torque of the target shaft based on the desired torque of the target shaft, the minimum value, and the first coefficient.

[0105] It should be noted that the motor's margin of capacity is relative to the boundary value. The requested torque does not exceed the motor's capacity, that is, the battery supply capacity is taken into account, and the reserve is called the motor's margin of capacity; the part that is less than the motor's capacity is called the gap, which is a negative value.

[0106] Optionally, when the desired torque of each axle is greater than or equal to 0, if the desired torque of each axle is greater than the positive torque boundary of the corresponding axle torque distribution wheel end, then the torque request for that axle is considered restricted. The three axle torque request restriction indicators are RaLimtdUp, MaLimtdUp, and FaLimtdUp, where 1 indicates restricted and 0 indicates unrestricted. RaLimtdUp corresponds to the rear axle, MaLimtdUp to the center axle, and FaLimtdUp to the front axle. If RaLimtdUp, MaLimtdUp, and FaLimtdUp are all equal to 1, then the system restriction flag SysLimtdUp = 1; otherwise, the system restriction flag SysLimtdUp = 0.

[0107] When all three axle torque requests are constrained (i.e., the system constraint flag SysLimtd = 1), the target torque of the target axle for inter-axle limited-slip coordination equals the wheel-end boundary value of the target axle, which is the ability of the motor capacity to be transferred to the wheel end. When all three axle torque requests are unconstrained, the front axle torque for inter-axle limited-slip coordination equals the desired front axle torque.

[0108] Taking the target axle as the front axle as an example, if two of the boundary constraint flags RaLimtd, MaLimtd, and FaLimtd are equal to 1 and FaLimtd is equal to 0, the target torque of the front axle for inter-axle limited slip coordination is: the desired torque of the front axle + min(front axle motor margin capacity, abs(middle axle motor capacity gap + rear axle motor capacity gap)) * first coefficient, where the first coefficient is: IF(desired torque of the front axle < 0, -1, 1). IF(condition, A, B) means that if the condition is met, take A; otherwise, take B.

[0109] In the technical solution of this embodiment, by calculating the target torque of the target shaft, the required torque of the target shaft, i.e. the desired torque, is transferred to other shafts with small or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the shaft with a high adhesion coefficient, which greatly improves the vehicle's passability, i.e., improves its ability to drive under different road conditions, especially its driving performance on complex or harsh roads.

[0110] Based on the first or second embodiment of this application, in the third embodiment of this application, the content that is the same as or similar to the above embodiments can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 5 Step S32 also includes:

[0111] Step S324: When the torque request of the target shaft is limited, and the torque request of one of the other two shafts is limited, a second coefficient is determined based on the expected torque magnitude of the target shaft.

[0112] Step S325: Determine the target torque of the target shaft based on the desired torque of the target shaft, the motor capacity gap of the target shaft, and the second coefficient.

[0113] Optionally, taking the target axle as the front axle as an example, if two of the boundary constraint flags RaLimtd, MaLimtd, and FaLimtd are equal to 1 and FaLimtd is equal to 1, the target torque of the front axle for inter-axle limited slip coordination is equal to the desired torque of the front axle plus the front axle motor capacity gap multiplied by the second coefficient, where the second coefficient is equal to IF(desired torque of the front axle < 0, -1, 1). IF(condition, A, B) means that if the condition is met, take A; otherwise, take B.

[0114] In the technical solution of this embodiment, by calculating the target torque of the target shaft, the required torque of the target shaft, i.e. the desired torque, is transferred to other shafts with small or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the shaft with a high adhesion coefficient, which greatly improves the vehicle's passability, i.e., improves its ability to drive under different road conditions, especially its driving performance on complex or harsh roads.

[0115] Based on any of the first to third embodiments of this application, in the fourth embodiment of this application, the content that is the same as or similar to the above embodiments can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 6 Step S32 also includes:

[0116] Step S326: When only the torque request of the target shaft is limited, a third coefficient is determined based on the expected torque magnitude of the target shaft;

[0117] Step S327: Determine the target torque of the target shaft based on the desired torque of the target shaft, the motor capacity gap of the target shaft, and the third coefficient.

[0118] Taking the target axis as the front axis as an example, if only one of the boundary limit flags RaLimtd, MaLimtd and FaLimtd is equal to 1 and FaLimtd is equal to 1, the front axis torque for inter-axis limited slip coordination is equal to the desired torque of the front axis + the front axis motor capacity gap * the third coefficient, where the third coefficient is equal to IF(desired torque of the front axis < 0, -1, 1), and IF(condition, A, B) means that if the condition is met, take A; otherwise, take B.

[0119] In the technical solution of this embodiment, by calculating the target torque of the target shaft, the required torque of the target shaft, i.e. the desired torque, is transferred to other shafts with small or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the shaft with a high adhesion coefficient, which greatly improves the vehicle's passability, i.e., improves its ability to drive under different road conditions, especially its driving performance on complex or harsh roads.

[0120] Based on any of the first to fourth embodiments of this application, in the fifth embodiment of this application, the content that is the same as or similar to the above embodiments can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 7 Step S32 also includes:

[0121] Step S328: When the torque request of one of the two axes other than the target axis is limited, a fourth coefficient is determined based on the expected torque magnitude of the target axis.

[0122] Step S329: Determine the product of the absolute value of the motor capacity gap of the other two axes and the preset torque axis transfer coordination factor, and determine the motor margin capacity of the target axis and the minimum value of the product.

[0123] Step S3210: Determine the target torque of the target shaft based on the desired torque of the target shaft, the minimum value, and the fourth coefficient.

[0124] Taking the target axle as the front axle as an example, if only one of the boundary limit flags RaLimtd, MaLimtd, and FaLimtd is equal to 1 and RaLimtd is equal to 1, meaning the rear axle torque request is limited, the product of the absolute value of the rear axle motor capacity gap and the preset torque inter-axle transfer coordination factor FacCvrt is determined; the minimum value of the front axle motor surplus capacity and the product is determined; the front axle torque for inter-axle limited slip coordination is determined based on the desired front axle torque, the minimum value, and the fourth coefficient. For example, the formula is as follows: Front axle torque for inter-axle limited slip coordination = Desired front axle torque + min(Front axle motor surplus capacity, abs(rear axle motor capacity gap) * torque inter-axle transfer coordination factor FacCvrt) * Fourth coefficient; where the fourth coefficient = IF(Desired front axle torque < 0, -1, 1).

[0125] Taking the target axle as the front axle as an example, if only one of the boundary limit flags RaLimtd, MaLimtd, and FaLimtd is equal to 1 and MaLimtd is equal to 1, meaning the center axle torque request is limited, determine the product of the absolute value of the center axle motor capacity shortfall and the torque-axis transfer coordination factor FacCvrt; determine the minimum value of the front axle motor surplus capacity and its product; and determine the front axle torque for inter-axle limited slip coordination based on the desired front axle torque, the minimum value, and the fourth coefficient. An example is shown in the following formula:

[0126] The front axle torque for inter-axle limited slip coordination = desired front axle torque + min(front axle motor margin capacity, abs(middle axle motor capacity gap) * torque inter-axle transfer coordination factor FacCvrt) * fourth coefficient; where the fourth coefficient = IF(desired front axle torque < 0, -1, 1).

[0127] In the technical solution of this embodiment, by calculating the target torque of the target shaft, the required torque of the target shaft, i.e. the desired torque, is transferred to other shafts with small or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the shaft with a high adhesion coefficient, which greatly improves the vehicle's passability, i.e., improves its ability to drive under different road conditions, especially its driving performance on complex or harsh roads.

[0128] Based on any of the first to fifth embodiments of this application, in the sixth embodiment of this application, the content that is the same as or similar to the above embodiments can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 8 Before step S329, the following are also included:

[0129] Step S3211: Determine the slip limit safety factor for each axis, wherein the slip limit safety factor is determined by the rate of change of motor slippage.

[0130] Step S3212: Determine the limited-slip safety factor based on the limited-slip safety coefficient;

[0131] Step S3213: Determine the effective capacity gap ratio, and determine the maximum torque fine-tuning safety factor based on the effective capacity gap ratio and the preset direction sign coefficient;

[0132] Step S3214: Determine the torque shaft transfer coordination factor based on the limited slip safety factor and the maximum torque fine-tuning safety factor.

[0133] The three axles are numbered 1 to 3 from front to back. If the torque of one axle is limited, the wheel slippage of the other two axles is formed into a vector and sorted in the vector according to the axle numbers from smallest to largest to obtain wheel slippage A and wheel slippage B.

[0134] Unsafe factor = the ratio of the rate of change of the slippage of the motor on this shaft to the rate of change threshold in the activation condition; slip limit safety factor = 1 - min(100, max(0, unsafe factor * (1 + positive gradient correction coefficient CorrFac))); where, the positive gradient correction coefficient CorrFac is obtained from the one-dimensional curve based on the gradient of wheel slippage A / wheel slippage B, and its value is limited to (0~1). Original gradient = (X(k) - X(kn)) / T(k) - T(kn); n = 5; the gradient is obtained by performing a first-order hysteresis filter on the original gradient.

[0135] The calculation of the limited-slip safety factor is as follows: Objective function = (limited-slip safety factor A - 1 + limited-slip safety factor B * (-1) + 1); When the inter-axis limited-slip single-axis restricted state > 0, the objective function is used as the actual safety input and 0 is the safety target, and PID closed-loop control is performed to calculate the limited-slip safety factor.

[0136] Considering that the initial value of the torque-axis transfer coordination factor FacCvrt differs when the torque is changed from unrestricted to single-axis torque-restricted, or from two-axis torque-restricted to single-axis torque-restricted, it is necessary to reset the I term of the closed-loop control of the torque-axis transfer coordination factor. The reset logic is as follows: Figure 9 As shown.

[0137] The calculation process for the maximum torque fine-tuning safety factor is illustrated in the following example.

[0138] Effective capacity gap (GAP) percentage = (min(absolute value of capacity gap of torque-limiting shaft * FacCvrt of the previous moment, surplus capacity of the shaft ranked first) + min(absolute value of capacity gap of torque-limiting shaft * (1 - FacCvrt of the previous moment), surplus capacity of the shaft ranked second)) / absolute value of capacity gap of torque-limiting shaft.

[0139] When the limited slip safety factor LimSlipSftyCorrFac < 0.001, the objective function = effective capacity gap (GAP) ratio * direction sign coefficient; otherwise, the objective function = 1.

[0140] When the inter-axis limited slip single-axis restricted state > 0, PID closed-loop control is performed with the objective function as the actual input and 1 as the objective, and the maximum torque fine-tuning safety factor is calculated.

[0141] The direction sign coefficient is introduced to resolve the conflict between the lack of directionality in the effective capacity GAP ratio and the need for positive or negative values ​​in the maximum torque fine-tuning safety factor calculated using it. When the limited-slip safety factor approaches and achieves the 0 safety target from a negative value, the direction sign coefficient = 1; when the limited-slip safety factor approaches and achieves the 0 safety target from a positive value, the direction sign coefficient = -1.

[0142] like Figure 10 As shown, the limited-slip safety factor and the maximum torque fine-tuning safety factor are obtained, and the sum of the limited-slip safety factor and the maximum torque fine-tuning safety factor is determined; the maximum value among 0 and the sum is determined, and the minimum value among 1 and the maximum value is determined; the torque shaft transfer coordination factor is determined based on the minimum value. For example, the torque shaft transfer coordination factor FacCvrt = min(1, max(0, limited-slip safety factor + maximum torque fine-tuning safety factor)).

[0143] In the technical solution of this embodiment, the target torque of the target shaft is further calculated by the torque shaft transfer coordination factor, and the required torque of the target shaft, i.e. the desired torque, is transferred to other shafts with small or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the shaft with a high adhesion coefficient, which greatly improves the vehicle's passability, that is, improves its ability to drive under different road conditions, especially its driving performance on complex or harsh roads.

[0144] Based on any of the first to sixth embodiments of this application, in the seventh embodiment of this application, the content that is the same as or similar to the above embodiments can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 11 The vehicle axle slip limiting method further includes:

[0145] Step S3215: When the expected torque of each shaft is greater than or equal to 0, if the expected torque of any shaft is less than or equal to the corresponding positive torque boundary, then the motor margin of any shaft is determined according to the difference between the positive torque boundary and the expected torque of any shaft.

[0146] Step S3216: If the desired torque of any shaft is greater than the positive torque boundary, then the motor capacity gap of any shaft is determined based on the difference between the positive torque boundary and the desired torque of any shaft.

[0147] Taking the target axle as the front axle as an example, when the desired torque of the rear axle is greater than or equal to 0, if the positive torque boundary of the front axle torque distribution wheel end is greater than or equal to the desired torque of the front axle, the front axle motor margin capacity = positive torque boundary of the front axle torque distribution wheel end - desired torque of the front axle; otherwise, the front axle motor margin capacity = 0.

[0148] When the desired torque of the front axle is greater than or equal to 0, if the positive torque boundary of the front axle torque distribution wheel end is less than the desired front axle torque, the front axle motor capacity gap = positive torque boundary of the front axle torque distribution wheel end - desired front axle torque; otherwise, the front axle motor capacity gap = 0.

[0149] The above describes the case where the desired torque of each axis is greater than or equal to 0. The logic is similar when the desired torque of each axis is less than 0.

[0150] In another feasible embodiment, when the expected torque of each shaft is less than 0, if the expected torque of any shaft is greater than or equal to the corresponding negative torque boundary, then the motor margin capacity of any shaft is determined based on the difference between the negative torque boundary and the expected torque of any shaft; if the expected torque of any shaft is less than the negative torque boundary, then the motor capacity gap of any shaft is determined based on the difference between the negative torque boundary and the expected torque of any shaft.

[0151] Taking the target axle as the front axle as an example, when the desired torque of the rear axle is less than 0, if the negative torque boundary of the front axle torque distribution wheel end is less than or equal to the desired torque of the front axle, the front axle motor margin capacity = abs(negative torque boundary of the front axle torque distribution wheel end - desired torque of the front axle); otherwise, the front axle motor margin capacity = 0.

[0152] When the desired torque of the front axle is less than 0, if the negative torque boundary of the front axle torque distribution wheel end is greater than the desired front axle torque, the front axle motor capacity gap = negative torque boundary of the front axle torque distribution wheel end - desired front axle torque; otherwise, the front axle motor capacity gap = 0.

[0153] In the technical solution of this embodiment, by determining the motor surplus capacity and motor capacity gap corresponding to each shaft, the target torque of the target shaft is further calculated, and the required torque of the target shaft, i.e. the desired torque, is transferred to other shafts with small or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the shaft with a high adhesion coefficient, which greatly improves the vehicle's passability, i.e., improves the ability to drive under different road conditions, especially its driving performance on complex or harsh roads.

[0154] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the vehicle inter-axle limited slip method of this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0155] This application provides a vehicle inter-axle slip limiting device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform the vehicle inter-axle slip limiting method in the above embodiment 1.

[0156] The following is for reference. Figure 12 The diagram illustrates a structural schematic suitable for implementing a vehicle inter-axle slip limiting device according to embodiments of this application. The vehicle inter-axle slip limiting device in embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), in-vehicle terminals (e.g., in-vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 12 The vehicle axle slip limiting device shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0157] like Figure 12As shown, the vehicle inter-axle limited slip device may include a processing unit 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the vehicle inter-axle limited slip device. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to I / O interface 1006: input devices 1007 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the vehicle inter-axle limited slip device to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows vehicle inter-axle limited slip devices with various systems, it should be understood that it is not required to implement or possess all the systems shown. More or fewer systems can be implemented or possessed alternatively.

[0158] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from ROM 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0159] The vehicle inter-axle limited-slip device provided in this application, employing the vehicle inter-axle limited-slip method in the above embodiments, can solve the technical problem that when a vehicle enters a low-speed situation or is struggling to get out of trouble, the TCS system cannot control slippage and extricate itself by reducing engine torque or braking the spinning wheels. Compared with the prior art, the beneficial effects of the vehicle inter-axle limited-slip device provided in this application are the same as those of the vehicle inter-axle limited-slip method provided in the above embodiments, and other technical features of this vehicle inter-axle limited-slip device are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0160] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0161] 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.

[0162] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the vehicle inter-axle limited slip method in the above embodiments.

[0163] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, 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, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0164] The aforementioned computer-readable storage medium may be included in the vehicle's inter-axle limited slip device; or it may exist independently and not be assembled into the vehicle's inter-axle limited slip device.

[0165] The aforementioned computer-readable storage medium carries one or more programs that, when executed by the vehicle inter-axle limited slip device, cause the vehicle inter-axle limited slip device to: coordinate the torque of the target axle and transfer the required torque, i.e. the desired torque, of the target axle to other axles with low or no slippage tendency. For the whole vehicle, the driving torque is adjusted to the axle with a high coefficient of adhesion, which greatly improves the vehicle's passability, i.e., improves its ability to drive under different road conditions, especially its driving performance on complex or harsh road surfaces.

[0166] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0167] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0168] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0169] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described vehicle inter-axle limited slip method. This solves the technical problem that when a vehicle enters a low-speed situation or is struggling to get out of trouble, the TCS system cannot control slippage and extricate itself by reducing engine torque or braking the spinning wheels. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the vehicle inter-axle limited slip method provided in the above embodiments, and will not be repeated here.

[0170] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the vehicle inter-axle limited slip method as described above.

[0171] The computer program product provided in this application can solve the technical problem that when a vehicle enters a low-speed situation or is struggling to get out of trouble, the TCS system cannot control slippage and extricate itself by reducing engine torque or braking the spinning wheels. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the vehicle inter-axle limited slip method provided in the above embodiments, and will not be repeated here.

[0172] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for limiting slip between vehicle axles, characterized in that, The method includes: When the differential lock of the vehicle is locked, the target shaft of the torque to be coordinated is determined, and the wheel slippage of the target shaft is greater than a preset threshold or the positive gradient of the wheel slippage is greater than a preset gradient value. Obtain the desired torque for each shaft and the corresponding wheel end boundary value for each shaft. The desired torque for each shaft is the pre-allocated wheel end torque. The wheel end boundary value includes the positive torque boundary and the negative torque boundary for torque allocation of each shaft. The positive torque boundary = (current actual motor torque - pre-slip torque reduction - closed-loop adjustment amount) × limited slip protection time factor. The negative torque boundary = (current actual motor torque + pre-slip torque reduction + closed-loop adjustment amount) × limited slip protection time factor. The target torque of the target shaft is determined based on the desired torque of each shaft and the wheel end boundary value. The step of determining the target torque of the target shaft based on the desired torque of each shaft and the wheel end boundary value includes: Based on the relationship between the expected torque of each shaft and the wheel end boundary value, the shaft with restricted torque request is determined; wherein, when the expected torque of each shaft is greater than or equal to 0, if the expected torque of any shaft is greater than the positive torque boundary, then the torque request of that shaft is determined to be restricted; when the expected torque of each shaft is less than 0, if the expected torque of any shaft is less than the negative torque boundary, then the torque request of that shaft is determined to be restricted. The target torque of the target shaft is determined based on the motor capacity gap of the shaft with limited torque request, wherein the motor capacity gap is the difference between the wheel end boundary value corresponding to the shaft with limited torque request and the desired torque.

2. The method as described in claim 1, characterized in that, The step of determining the target torque of the target shaft based on the desired torque of each shaft and the wheel end boundary value includes: When the desired torque of each axle of the vehicle is greater than the positive torque boundary of the wheel end for torque distribution of each axle, the target torque of the target axle for inter-axle limited slip coordination is determined according to the desired torque of each axle and the positive torque boundary.

3. The method as described in claim 1, characterized in that, The step of determining the torque of the target shaft based on the desired torque of each shaft and the wheel end boundary value includes: When the desired torque of each axle of the vehicle is less than the negative torque boundary of the wheel end for torque distribution of each axle, the target torque of the target axle for inter-axle limited slip coordination is determined based on the desired torque of each axle and the negative torque boundary.

4. The method as described in claim 1, characterized in that, When the vehicle is a three-axle vehicle, the step of determining the target torque of the target axle based on the motor capacity gap of the axle with the limited torque request includes: When the shafts with limited torque requests include two other shafts besides the target shaft, determine the absolute value of the sum of the motor capacity gaps of the other two shafts, and determine the minimum value between the motor margin capacity of the target shaft and the absolute value; the motor margin capacity is determined by the difference between the wheel end boundary value corresponding to the target shaft and the desired torque; The first coefficient is determined based on the magnitude of the desired torque of the target shaft; The target torque of the target shaft is determined based on the desired torque of the target shaft, the minimum value, and the first coefficient.

5. The method as described in claim 1, characterized in that, When the vehicle is a three-axle vehicle, the step of determining the target torque of the target axle based on the motor capacity gap of the axle with the limited torque request includes: When the torque request of the target shaft is limited, and the torque request of one of the other two shafts is limited, a second coefficient is determined based on the expected torque magnitude of the target shaft. The target torque of the target shaft is determined based on the desired torque of the target shaft, the motor capacity gap of the target shaft, and the second coefficient.

6. The method as described in claim 1, characterized in that, When the vehicle is a three-axle vehicle, the step of determining the target torque of the target axle based on the motor capacity gap of the axle with the limited torque request includes: When the torque request of only the target shaft is limited, a third coefficient is determined based on the expected torque magnitude of the target shaft; The target torque of the target shaft is determined based on the desired torque of the target shaft, the motor capacity gap of the target shaft, and the third coefficient.

7. The method as described in claim 1, characterized in that, When the vehicle is a three-axle vehicle, the step of determining the target torque of the target axle based on the motor capacity gap of the axle with the limited torque request includes: When the torque request of one of the two axes other than the target axis is limited, a fourth coefficient is determined based on the expected torque magnitude of the target axis; The product of the absolute value of the motor capacity gap of the other two axes and the preset torque axis transfer coordination factor is determined, and the motor margin of the target axis and the minimum value of the product are determined; the motor margin is determined by the difference between the wheel end boundary value corresponding to the target axis and the desired torque; The target torque of the target shaft is determined based on the desired torque of the target shaft, the minimum value, and the fourth coefficient.

8. The method as described in claim 7, characterized in that, Before the step of determining the product of the absolute value of the motor capacity gap of the other two axes and a preset torque axis transfer coordination factor, the method further includes: Determine the slip limit safety factor for each axis, wherein the slip limit safety factor is determined by the rate of change of motor slippage; Based on the aforementioned slip-limiting safety factor, determine the slip-limiting safety factor; Determine the effective capacity gap ratio, and determine the maximum torque fine-tuning safety factor based on the effective capacity gap ratio and the preset direction sign coefficient; Based on the limited-slip safety factor and the maximum torque fine-tuning safety factor, the torque shaft transfer coordination factor is determined.

9. The method according to any one of claims 3 to 8, characterized in that, The method includes: When the desired torque of each shaft is greater than or equal to 0, if the desired torque of any shaft is less than or equal to the corresponding positive torque boundary, then the motor margin of any shaft is determined based on the difference between the positive torque boundary and the desired torque of any shaft; the motor margin is determined by the difference between the wheel end boundary value corresponding to any shaft and the desired torque. If the desired torque of any shaft is greater than the positive torque boundary, then the motor capacity gap of any shaft is determined based on the difference between the positive torque boundary and the desired torque of any shaft.

10. The method according to any one of claims 3 to 8, characterized in that, The method includes: When the expected torque of each shaft is less than 0, if the expected torque of any shaft is greater than or equal to the corresponding negative torque boundary, then the motor margin of any shaft is determined based on the difference between the negative torque boundary and the expected torque of any shaft; the motor margin is determined by the difference between the wheel end boundary value corresponding to any shaft and the expected torque. If the desired torque of any shaft is less than the negative torque boundary, then the motor capacity gap of any shaft is determined based on the difference between the negative torque boundary and the desired torque of any shaft.

11. The method as described in claim 1, characterized in that, The steps for obtaining the wheel end boundary values ​​corresponding to each shaft include: The pre-slip torque of any axis is determined based on the difference between the actual torque of the current motor on any axis and the pre-slip torque reduction of any axis and the preset closed-loop adjustment amount. The wheel end boundary value of any axle is determined by multiplying the difference with the preset limited-slip protection time factor.

12. A vehicle axle slip limiting device, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the vehicle inter-axle limited slip method as described in any one of claims 1 to 11.

13. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the vehicle inter-axle limited slip method as described in any one of claims 1 to 11.

14. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the steps of the vehicle inter-axle limited slip method as described in any one of claims 1 to 11.

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