Torque distribution control method and system for front and rear axles of four-wheel-drive vehicle, medium and product

Abstract

The invention relates to the technical field of vehicle control, in particular to a torque distribution control method and system for front and rear axles of a four-wheel-drive vehicle, a medium and a product. Comprising the following steps: correcting a vehicle yaw velocity deviation to obtain a final yaw velocity deviation; correcting the actual yaw velocity to obtain an actual yaw velocity deviation; based on the actual yaw velocity deviation and the final yaw velocity deviation, correcting the original front and rear axle torque distribution coefficient to obtain a theoretical front and rear axle torque distribution adjustment coefficient; obtaining a final front-rear shaft torque distribution coefficient based on the theoretical front-rear shaft torque distribution adjustment coefficient and the original front-rear shaft torque distribution coefficient; and distributing the front and rear axle torques of the four-wheel-drive vehicle according to the final front and rear axle torque distribution coefficient. The torque distribution control method for the front axle and the rear axle of the four-wheel-drive vehicle is simple, the current steering intention of a driver is better met, and torque distribution control over the front axle and the rear axle is more accurate and sensitive.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to a method, system, medium and product for controlling front and rear axle torque distribution of a four-wheel drive vehicle. Background Art

[0002] Currently, four-wheel independent distributed drive vehicles in the industry are still in the concept car stage or immature stage, and the torque distribution of the front, rear, left and right wheels in corners is still in the matching and exploratory stage.

[0003] In related technologies, when a vehicle is turning, the front and rear axle torque distribution coefficient can be determined by calculating the deviation between the actual yaw rate and the target yaw rate, and then the vehicle yaw can be controlled based on the front and rear axle torque distribution coefficient.

[0004] For example, the prior art entitled "Distributed Torque Distribution Method, Device, Vehicle and Storage Medium for Vehicle" proposes a torque distribution method, which includes the following steps: when the vehicle is in a four-wheel drive distributed driving mode, identifying the current steering condition of the vehicle; when the current steering condition is an understeering condition or an oversteering condition, obtaining the actual yaw angular velocity of the vehicle, and determining the torque distribution mode of the vehicle based on the speed value of the actual yaw angular velocity, the speed difference between the actual yaw angular velocity and the target yaw angular velocity, or the speed change rate; based on the torque distribution mode, calculating the target torque of at least one drive shaft or at least one drive wheel of the vehicle under the understeering condition or the oversteering condition, respectively.

[0005] This method can distribute torque according to the change of vehicle yaw angular velocity to calculate the driving torque under different working conditions respectively, thereby actively reducing or increasing yaw torque to improve understeer or oversteer, improve vehicle steering stability, and effectively ensure vehicle safety.

[0006] However, this method also has some problems. It uses sensors to collect steering wheel angles and actual yaw angles for control. However, in actual application, this control mode has large deviations and cannot accurately match the current driver's steering intentions. The final yaw control effect is poor. Summary of the Invention

[0007] The purpose of this application is to address the deficiencies of the above-mentioned background technology and to provide a method, system, medium and product for controlling the torque distribution between the front and rear axles of a four-wheel drive vehicle.

[0008] The technical solution of this application is: a method for controlling the torque distribution between the front and rear axles of a four-wheel drive vehicle, comprising: When the four-wheel drive vehicle turns, the actual yaw rate of the vehicle is collected, and the vehicle yaw rate deviation and the original front and rear axle torque distribution coefficient are obtained; correcting the vehicle yaw rate error to obtain a final yaw rate error; correcting the actual yaw rate to obtain an actual yaw rate error; correcting the original front-rear axle torque distribution coefficient based on the actual yaw rate error and the final yaw rate error to obtain a theoretical front-rear axle torque distribution adjustment coefficient; obtaining a final front-rear axle torque distribution coefficient based on the theoretical front-rear axle torque distribution adjustment coefficient and the original front-rear axle torque distribution coefficient; distributing the front-rear axle torque of the four-wheel drive vehicle according to the final front-rear axle torque distribution coefficient.

[0009] According to the four-wheel drive vehicle front-rear axle torque distribution control method provided by the application, the method of obtaining a final front-rear axle torque distribution coefficient based on a theoretical front-rear axle torque distribution adjustment coefficient and an original front-rear axle torque distribution coefficient comprises: correcting the theoretical front-rear axle torque distribution adjustment coefficient to obtain a limited front-rear axle torque distribution adjustment coefficient; and taking the sum of the limited front-rear axle torque distribution adjustment coefficient and the original front-rear axle torque distribution coefficient as the final front-rear axle torque distribution coefficient.

[0010] According to the four-wheel drive vehicle front-rear axle torque distribution control method provided by the application, the method of correcting the theoretical front-rear axle torque distribution adjustment coefficient to obtain a limited front-rear axle torque distribution adjustment coefficient comprises: obtaining a theoretical front-rear axle torque distribution coefficient upper limit and a theoretical front-rear axle torque distribution coefficient lower limit based on a calibrated vehicle reference acceleration, a driver demand torque, a theoretical front-rear axle torque distribution coefficient upper limit and a theoretical front-rear axle torque distribution coefficient lower limit two-dimensional table; when the theoretical front-rear axle torque distribution coefficient is between the theoretical front-rear axle torque distribution coefficient lower limit and the original front-rear axle torque distribution coefficient, taking the theoretical front-rear axle torque distribution coefficient as the limited front-rear axle torque distribution adjustment coefficient; when the theoretical front-rear axle torque distribution coefficient is less than the theoretical front-rear axle torque distribution coefficient lower limit and the original front-rear axle torque distribution coefficient, taking the difference between the theoretical front-rear axle torque distribution coefficient lower limit and the original front-rear axle torque distribution coefficient as the limited front-rear axle torque distribution adjustment coefficient; when the theoretical front-rear axle torque distribution coefficient is greater than the theoretical front-rear axle torque distribution coefficient lower limit and the original front-rear axle torque distribution coefficient, taking the difference between the theoretical front-rear axle torque distribution coefficient upper limit and the original front-rear axle torque distribution coefficient as the limited front-rear axle torque distribution adjustment coefficient.

[0011] According to a front and rear axle torque distribution control method for a four-wheel drive vehicle provided by the present application, the method of correcting an original front and rear axle torque distribution coefficient based on an actual yaw rate deviation and a final yaw rate deviation to obtain a theoretical front and rear axle torque distribution adjustment coefficient includes: obtaining a vehicle reference acceleration based on a vehicle lateral acceleration and a vehicle longitudinal acceleration; obtaining a final front and rear axle torque distribution coefficient adjustment proportional term and a final front and rear axle torque distribution coefficient adjustment integral term based on the actual yaw rate deviation, the vehicle reference acceleration, the driver's required torque, and the absolute value of the lateral acceleration; Obtaining a vehicle yaw control enable state for determination, adjusting the proportional term based on the absolute value of the lateral acceleration and the final front and rear axle torque distribution coefficient according to the vehicle yaw control enable state to obtain a front and rear axle torque distribution proportional term adjustment coefficient, and adjusting the integral term based on the vehicle yaw control enable state and the final front and rear axle torque distribution coefficient to obtain a front and rear axle torque distribution integral term adjustment coefficient; The sum of the front-rear axle torque distribution proportional item adjustment coefficient and the front-rear axle torque distribution integral item adjustment coefficient is used as the theoretical front-rear axle torque distribution adjustment coefficient.

[0012] According to a front and rear axle torque distribution control method for a four-wheel drive vehicle provided by the present application, the method of obtaining a front and rear axle torque distribution proportional term adjustment coefficient based on the absolute value of the lateral acceleration and the final front and rear axle torque distribution coefficient adjustment proportional term according to the vehicle yaw control enable state includes: when the vehicle yaw control is enabled, the front and rear axle torque distribution proportional term adjustment coefficient is the product of the final front and rear axle torque distribution coefficient adjustment proportional term and the final yaw angular velocity deviation; When the vehicle yaw angle control is not enabled, the front and rear axle torque distribution ratio adjustment coefficient is 0.

[0013] According to a front and rear axle torque distribution control method for a four-wheel drive vehicle provided by the present application, the method of adjusting the integral term according to the vehicle yaw control enable state and the final front and rear axle torque distribution coefficient to obtain the front and rear axle torque distribution integral term adjustment coefficient comprises: obtaining the front and rear axle torque distribution pre-control adjustment coefficient based on a calibrated two-dimensional table of driver demand torque, lateral acceleration absolute value, and front and rear axle torque distribution pre-control adjustment coefficient; obtaining the front and rear axle torque distribution integral term pre-control adjustment coefficient based on the front and rear axle torque distribution pre-control adjustment coefficient, the original front and rear axle torque distribution coefficient, and the front and rear axle torque distribution proportional term adjustment coefficient; When the vehicle yaw control is switched from unenabled to enabled, the front and rear axle torque distribution integral term adjustment coefficient is the front and rear axle torque distribution integral term pre-control adjustment coefficient; When vehicle yaw control is enabled, the front and rear axle torque distribution integral term adjustment coefficient is the product of the final front and rear axle torque distribution coefficient adjustment integral term and the final yaw rate deviation; When the vehicle yaw angle control is not enabled, the front and rear axle torque distribution integral adjustment coefficient is 0.

[0014] The method for obtaining the integral term pre-control adjustment coefficient of the front-rear axle torque distribution according to the front-rear axle torque distribution pre-control adjustment coefficient, the original front-rear axle torque distribution coefficient and the front-rear axle torque distribution proportional term adjustment coefficient comprises: the integral term pre-control adjustment coefficient of the front-rear axle torque distribution is the difference between the front-rear axle torque distribution pre-control adjustment coefficient, the original front-rear axle torque distribution coefficient and the front-rear axle torque distribution proportional term adjustment coefficient.

[0015] The method for obtaining the final front-rear axle torque distribution coefficient adjustment proportional term based on the actual yaw rate deviation, the vehicle reference acceleration, the driver demand torque and the lateral acceleration absolute value comprises: obtaining the front-rear axle torque distribution coefficient adjustment proportional term based on a two-dimensional table of the calibrated actual yaw rate deviation, the vehicle reference acceleration and the front-rear axle torque distribution coefficient adjustment proportional term; obtaining the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment proportional term based on a two-dimensional table of the calibrated driver demand torque, the final yaw rate deviation and the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment proportional term; obtaining the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment proportional term based on a two-dimensional table of the calibrated driver demand torque, the lateral acceleration absolute value and the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment proportional term; The final front-rear axle torque distribution coefficient adjustment proportional term is the product of the front-rear axle torque distribution coefficient adjustment proportional term, the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment proportional term and the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment proportional term.

[0016] The method for obtaining the final front-rear axle torque distribution coefficient adjustment integral term based on the actual yaw rate deviation, the vehicle reference acceleration, the driver demand torque and the lateral acceleration absolute value comprises: obtaining the front-rear axle torque distribution coefficient adjustment integral term based on a two-dimensional table of the calibrated actual yaw rate deviation, the vehicle reference acceleration and the front-rear axle torque distribution coefficient adjustment integral term; obtaining the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term based on a two-dimensional table of the calibrated driver demand torque, the final yaw rate deviation and the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term; obtaining the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term based on a two-dimensional table of the calibrated driver demand torque, the lateral acceleration absolute value and the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term; The final front-rear axle torque distribution coefficient adjustment integral term is a product of the front-rear axle torque distribution coefficient adjustment integral term, a deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term, and an acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term.

[0017] According to the four-wheel drive vehicle front-rear axle torque distribution control method provided in the application, the method for obtaining the vehicle reference acceleration based on the vehicle lateral acceleration and the vehicle longitudinal acceleration comprises: obtaining the initial reference acceleration of the current period based on the vehicle lateral acceleration and the vehicle longitudinal acceleration. When there is an external torque increase or decrease request, the vehicle reference acceleration = the initial reference acceleration of the current period * the first weight coefficient + the reference acceleration of the last period * the second weight coefficient… the reference acceleration of the N-1 period * the N weight coefficient, and the first weight coefficient + the second weight coefficient… + the N weight coefficient = 1. When there is no external torque increase or decrease request, if the current vehicle speed is greater than the set speed threshold, the vehicle reference acceleration is the larger one of the initial reference acceleration of the current period and the reference acceleration of the last period, and if the current vehicle speed is not greater than the set speed threshold, the vehicle reference acceleration is the reference acceleration of the last period.

[0018] According to the four-wheel drive vehicle front-rear axle torque distribution control method provided in the application, the method for correcting the vehicle yaw rate deviation to obtain the final yaw rate deviation comprises: obtaining the original yaw rate deviation based on the actual yaw rate and the target yaw rate; determining the upper limit and the lower limit of the yaw rate deviation dead zone based on the calibrated steering wheel angle change rate, the absolute value of the lateral acceleration, and the upper limit and the lower limit of the yaw rate deviation dead zone; When the original yaw rate deviation ≥ the upper limit of the yaw rate deviation dead zone, the final yaw rate deviation is the difference between the original yaw rate deviation and the upper limit of the yaw rate deviation dead zone; When the original yaw rate deviation ≤ the lower limit of the yaw rate deviation dead zone, the final yaw rate deviation is the difference between the original yaw rate deviation and the lower limit of the yaw rate deviation dead zone; When the original yaw rate deviation is between the upper limit of the yaw rate deviation dead zone and the lower limit of the yaw rate deviation dead zone, the final yaw rate deviation is 0.

[0019] According to the four-wheel drive vehicle front-rear axle torque distribution control method provided in the application, the method for obtaining the original yaw rate deviation based on the actual yaw rate and the target yaw rate comprises: when the actual yaw rate>0 and the target yaw rate<0, or the actual yaw rate<0 and the target yaw rate>0, the original yaw rate deviation is the sum of the absolute value of the actual yaw rate and the absolute value of the target yaw rate; otherwise, the original yaw rate deviation is the difference between the absolute value of the actual yaw rate and the absolute value of the target yaw rate.

[0020] According to the four-wheel drive vehicle front-rear axle torque distribution control method provided in the application, the method for correcting the actual yaw rate to obtain the actual yaw rate deviation comprises: obtaining an initial actual yaw rate deviation based on the lateral acceleration, the vehicle speed and the actual yaw rate; when the vehicle speed is in a set vehicle speed range, the actual yaw rate deviation is the absolute value of the first-order low-pass filtered value of the initial actual yaw rate deviation, and when the vehicle speed is not in the set vehicle speed range, the actual yaw rate deviation is the initial actual yaw rate deviation.

[0021] According to the four-wheel drive vehicle front-rear axle torque distribution control method provided in the application, when the TCS is actuated, the final front-rear axle torque distribution coefficient in the current period is the final front-rear axle torque distribution coefficient in the last period.

[0022] The application also relates to a control system which operates according to the four-wheel drive vehicle front-rear axle torque distribution control method, comprising, a first correction module configured to correct the vehicle yaw rate deviation to obtain a final yaw rate deviation; a second correction module configured to correct the actual yaw rate to obtain an actual yaw rate deviation; a third correction module configured to correct an original front-rear axle torque distribution coefficient based on the actual yaw rate deviation and the final yaw rate deviation to obtain a theoretical front-rear axle torque distribution adjustment coefficient; a distribution coefficient determination module configured to obtain a final front-rear axle torque distribution coefficient based on the theoretical front-rear axle torque distribution adjustment coefficient and the original front-rear axle torque distribution coefficient; an execution module configured to distribute the front-rear axle torque of the four-wheel drive vehicle according to the final front-rear axle torque distribution coefficient.

[0023] According to the control system provided in the application, the control system further comprises, a collection module configured to collect the actual yaw rate of the vehicle; an acquisition module configured to acquire the vehicle yaw rate deviation and the original front-rear axle torque distribution coefficient.

[0024] The present application also relates to a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned method for controlling the torque distribution between the front and rear axles of a four-wheel drive vehicle.

[0025] The present application also relates to a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the steps of the above-mentioned method for controlling the torque distribution between the front and rear axles of a four-wheel drive vehicle.

[0026] The advantages of the present application are as follows: 1. The present application provides a method for controlling the torque distribution between the front and rear axles of a four-wheel drive vehicle. The present application corrects the vehicle's yaw rate deviation and the actual yaw rate, thereby obtaining a final yaw rate deviation and an actual yaw rate deviation. The calculation of the final front and rear axle torque distribution coefficient based on the final yaw rate deviation is more consistent with the driver's current steering intention, reduces the frequent adjustment of the yaw deviation when the steering wheel angle change rate is not large, and improves the rapid adjustment of the yaw deviation when the steering wheel angle change rate is large. The introduction of the actual yaw rate deviation can eliminate the deviation caused by directly using the yaw rate, making the calculation result of the final front and rear axle torque distribution coefficient more accurate, and can accurately adjust the front and rear axle torque distribution of the four-wheel drive vehicle during the steering process. The overall calculation is accurate and the adjustment is more sensitive. 2. The final front-to-rear axle torque distribution coefficient obtained in this application is obtained by modifying the original front-to-rear axle torque distribution coefficient by limiting the rear axle torque distribution adjustment coefficient. Compared to directly using the original front-to-rear axle torque distribution coefficient as the final front-to-rear axle torque distribution coefficient, all adjustments in this application are concentrated on this parameter of the limited rear axle torque distribution adjustment coefficient. When the yaw control function is abnormal, only the limited rear axle torque distribution adjustment coefficient needs to be disabled. The original front-to-rear axle torque distribution coefficient can still be used to meet driving and steering requirements, and the control strategy is more stable and safe. 3. This application modifies the theoretical front-to-rear axle torque distribution adjustment coefficient to obtain a limited front-to-rear axle torque distribution adjustment coefficient. By designing the upper and lower limits of the theoretical front-to-rear axle torque distribution coefficient based on the vehicle reference acceleration and the driver's required torque, different adjustment intensity limits can be achieved under different conditions to ensure a safety margin. For example, under high throttle and rapid acceleration, the adjustment intensity can be appropriately lowered to avoid excessive response and loss of control. This adjustment method can improve the safety of four-wheel drive vehicles when turning. 4. The application obtains a theoretical front and rear axle torque distribution adjustment coefficient, the correction analysis method fully considers the accuracy of the actual yaw rate by introducing the actual yaw rate deviation, and fully considers the driver's intention and the actual driving state of the vehicle by introducing the vehicle reference acceleration, the driver's demand torque and the lateral acceleration, so that the final adjustment control can more accurately fit the driver's demand and the vehicle state, and the control is more accurate and reasonable; 5. The application determines the front and rear axle torque distribution proportion item adjustment coefficient based on the vehicle yaw control enabled state, fully considers the current vehicle yaw control state, and is consistent with the actual driving state of the vehicle. When the yaw control is enabled, additional adjustment is needed. When the yaw control is not enabled, the original front and rear axle torque distribution coefficient can be used. The calculation method is simple, easy to operate and implement, and the control is more sensitive; 6. The application determines the front and rear axle torque distribution integral item adjustment coefficient according to the vehicle yaw control enabled state. The front and rear axle torque distribution integral item adjustment coefficient is related to the calculation of the theoretical front and rear axle torque distribution adjustment coefficient. By accurately calculating the front and rear axle torque distribution integral item adjustment coefficient, the response period is greatly shortened. At the same time, the calculation of the front and rear axle torque distribution integral item adjustment coefficient is closed-loop pre-controlled, and the final front and rear axle torque distribution coefficient is accurately obtained, so that the front and rear axle torque regulation of the four-wheel drive vehicle is more sensitive; 7. In the process of determining the front and rear axle torque distribution integral item adjustment coefficient, the front and rear axle torque distribution integral item pre-control adjustment coefficient is introduced. Pre-controlling the front and rear axle torque distribution integral item adjustment coefficient can speed up the adjustment response. However, excessive front and rear axle torque distribution integral item pre-control adjustment coefficient or causes response loss. Therefore, the application obtains a suitable front and rear axle torque distribution integral item pre-control adjustment coefficient by subtracting the original front and rear axle torque distribution coefficient and the front and rear axle torque distribution proportion item adjustment coefficient, which can meet the high sensitivity response and avoid response loss; 8. In the process of determining the front and rear axle torque distribution proportion item adjustment coefficient, it is obtained by calculating the final front and rear axle torque distribution coefficient adjustment proportion item. The accuracy of the actual yaw rate is considered by introducing the actual yaw rate deviation, and the driver's intention and the actual driving state of the vehicle are considered by introducing the vehicle reference acceleration, the driver's demand torque and the lateral acceleration. These calculation methods make the final adjustment control more accurately fit the driver's demand and the vehicle state, and the control is more accurate and reasonable; 9. The method for determining the final front-to-rear axle torque distribution coefficient adjustment integral term in this application is very simple. Determination of the final front-to-rear axle torque distribution coefficient adjustment integral term can yield the front-to-rear axle torque distribution integral term adjustment coefficient. Similarly, the accuracy of the actual yaw rate is fully considered during the calculation of the final front-to-rear axle torque distribution coefficient adjustment integral term, ensuring that the calculation result truly reflects the driver's intention and the actual driving state of the vehicle, and that the corresponding control method is reasonable. 10. This application modifies the initial vehicle reference acceleration based on the vehicle lateral acceleration and the vehicle longitudinal acceleration to obtain the vehicle reference acceleration. When there is an external torque increase or decrease request, the vehicle acceleration will change. Considering that the torque request duration is very short and will be quickly restored, this application uses the estimated vehicle reference acceleration for control, which will significantly improve the smoothness of vehicle control and avoid transient jumps. When there is no external torque increase or decrease request, at high vehicle speeds, the vehicle reference acceleration is used as the larger value of the current cycle initial reference acceleration or the previous cycle reference acceleration. This allows control to be performed using the larger value as the input variable, achieving more conservative regulation and further improving safety. 11. The final yaw rate deviation obtained in this application is obtained by comparing the original yaw rate deviation with the upper and lower limits of the yaw rate deviation dead zone. This can reduce the frequent adjustment of the yaw deviation when the steering wheel angle change rate is small, and improve the rapid adjustment of the yaw deviation when the steering wheel angle change rate is large. 12. This application compares the actual yaw rate with the target yaw rate to obtain an original yaw rate deviation. In conventional control, the actual yaw rate is generally measured by a Yaw-G sensor. However, the Yaw-G sensor may experience zero drift when driving in a straight line or at low speeds, resulting in inaccurate measurement. Therefore, a parameter called actual yaw rate deviation is proposed. At low vehicle speeds, an actual yaw rate is calculated based on a simplified steering model theory. The actual yaw rate deviation is the deviation between the theoretical calculated value and the sensor measured value. The actual yaw rate deviation is then introduced into the subsequent torque distribution control to improve the accuracy of yaw control at low speeds. 13. The method for correcting the actual yaw rate in this application is very simple. It corrects the initial actual yaw rate deviation based on the vehicle speed, eliminating the error problem existing in directly obtaining the vehicle speed, improving the calculation accuracy, and making the torque distribution adjustment more sensitive. 14. This application adopts another method for calculating the final front and rear axle torque distribution coefficient when the TCS is activated, supplementing the control strategy when the TCS is activated. This avoids mismatching caused by simultaneous adjustments or affecting the TCS control effect, improves the smoothness of the four-wheel drive vehicle's torque control, and makes the torque distribution control of the entire four-wheel drive vehicle clearer. 15. The present application also relates to a control system. The control system of the present application integrates the above-mentioned control method. The control system of the present application can correct the vehicle yaw rate deviation and the actual yaw rate, thereby obtaining a final yaw rate deviation and an actual yaw rate deviation. The calculation of the final front and rear axle torque distribution coefficient based on the final yaw rate deviation is more consistent with the driver's current steering intention. The introduction of the actual yaw rate deviation can eliminate the deviation caused by directly using the yaw rate, making the calculation result of the final front and rear axle torque distribution coefficient more accurate. The front and rear axle torque distribution of the four-wheel drive vehicle during the steering process can be precisely adjusted, and the overall calculation is accurate and the adjustment is more sensitive. 16. The present application also involves storage media and program products, that is, the control method of the present application can be transformed into different forms, which is convenient for application in the front and rear axle torque distribution control technology of four-wheel drive vehicles, and has a very wide range of applications.

[0027] The front and rear axle torque distribution control method of a four-wheel drive vehicle in the present application is simple. Compared with the existing front and rear axle torque distribution method of a four-wheel drive vehicle, the control method of the present application is more in line with the driver's current steering intention, and the front and rear axle torque distribution control is more precise and sensitive, and is suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 : Flowchart of the front and rear axle torque distribution control method of a four-wheel drive vehicle of the present application. DETAILED DESCRIPTION

[0029] The embodiments of the present application are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0030] In the description of this application, it should be understood that the terms "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0031] In addition, the terms "first", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an ordered ranking of the indicated technical features. Thus, features defined with "first", "second" etc. can include one or more such features explicitly or implicitly. In the description of the present application, "a plurality of" means at least two, for example two, three, etc., unless explicitly specified otherwise.

[0032] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] The present application relates to a kind of four-wheel drive vehicle front and rear axle torque distribution control method, the control method of the present application is mainly used for four-wheel drive vehicle in steering state front and rear axle torque distribution, by accurately calculating the final front and rear axle torque distribution coefficient of four-wheel drive vehicle in steering state, and according to final front and rear axle torque distribution coefficient, four-wheel drive front and rear axle torque is distributed control, can accurately control and adjust the torque of four-wheel drive vehicle in steering state, the control method of the present application belongs to closed loop control.Compared with the prior art four-wheel drive vehicle front and rear axle torque distribution control method, the present application has been modified to vehicle yaw angular velocity deviation and actual yaw angular velocity, so as to obtain final yaw angular velocity deviation and actual yaw angular velocity deviation, based on final yaw angular velocity deviation the calculation of final front and rear axle torque distribution coefficient is more in line with the current steering intention of driver, introduce actual yaw angular velocity deviation can eliminate the error caused by directly using yaw angular velocity, so that the calculation result of final front and rear axle torque distribution coefficient is more accurate, can accurately adjust four-wheel drive vehicle front and rear axle torque distribution in steering process, overall calculation is accurate, and adjustment is more sensitive.

[0034] Specifically, a kind of four-wheel drive vehicle front and rear axle torque distribution control method of the present application, as shown in Figure 1 The following steps can be carried out: S1, when four-wheel drive vehicle appears steering, the actual yaw angular velocity of vehicle is collected, and vehicle yaw angular velocity deviation and original front and rear axle torque distribution coefficient are obtained; The present application is to control and adjust the distribution of front and rear axle torque of a four-wheel drive vehicle when turning, and to collect the actual yaw rate of the vehicle when turning. This can be collected by the sensor installed in the power domain. The vehicle yaw rate deviation is the deviation between the actual yaw rate and the target yaw rate. The target yaw rate (the target yaw rate refers to the expected vehicle yaw rate at different steering wheel angles. By designing a two-dimensional calibration table, the horizontal axis is the vehicle speed, the vertical axis is the steering wheel angle, and the output is the target yaw rate. When using it, the calibration table is called to obtain the target yaw rate based on the vehicle speed and steering wheel angle) is obtained according to the steering wheel angle The original front and rear axle torque distribution coefficient (the original front and rear axle torque distribution coefficient refers to the front and rear axle torque distribution without considering steering adjustment. By designing a two-dimensional calibration table, the horizontal axis is the vehicle speed, the vertical axis is the driver's required torque, and the output is the target yaw rate, the calibration table is called to input the vehicle speed and the driver's required torque to obtain the original front and rear axle torque distribution coefficient. During large acceleration or sudden acceleration, the front axle distribution coefficient = front axle load / total front and rear axle load.) is a basic distribution coefficient determined according to vehicle speed, driver's required torque, and axle load ratio. It can be obtained through the power domain controller or vehicle controller. S2. Correcting the vehicle yaw rate deviation to obtain a final yaw rate deviation; Compared to traditional four-wheel drive vehicle front and rear axle torque distribution control technologies that use the vehicle's yaw rate deviation as the analysis object, the present application corrects the vehicle's yaw rate deviation. The purpose of this correction is to, on the one hand, reduce the frequent adjustment of the yaw deviation when the steering wheel angle change rate is small (such as when making small turns on a curved road) (expanding the range where the final yaw rate deviation is 0, thereby reducing the frequency of adjustment actuation), and, on the other hand, improve the rapid adjustment of the yaw deviation when the steering wheel angle change rate is large (such as when making emergency steering turns to avoid danger) (faster identification of the final yaw rate deviation, thereby quickly executing the adjustment). This can eliminate the error caused by calculating the final front and rear axle torque distribution coefficient based on the measured yaw rate deviation, so that the final calculated front and rear axle torque distribution coefficient is more consistent with the driver's control intention, providing a better driving experience. S3. Correcting the actual yaw rate to obtain an actual yaw rate deviation; The actual yaw rate deviation is obtained and used as the basis for subsequent calculations. In conventional control, the actual yaw rate is generally measured by a Yaw-G sensor. However, the Yaw-G sensor may experience zero drift during straight-line driving or low-speed driving, resulting in inaccurate measurements. Therefore, the actual yaw rate deviation parameter is proposed and incorporated into the subsequent torque distribution control to improve yaw control accuracy at low speeds and make the final front and rear axle torque distribution control more sensitive. S4, correcting the original front and rear axle torque distribution coefficient based on the actual yaw rate deviation and the final yaw rate deviation to obtain a theoretical front and rear axle torque distribution adjustment coefficient; The theoretical front-to-rear axle torque distribution adjustment coefficient is a correction to the original front-to-rear axle torque distribution coefficient, which is determined based on vehicle speed, driver-requested torque, and axle load ratio. By further correcting the original front-to-rear axle torque distribution coefficient and using the actual yaw rate deviation to assess the accuracy of the actual yaw rate, the final adjustment control more accurately matches the driver's needs and vehicle status, resulting in more precise and reasonable control. S5, obtaining a final front-rear axle torque distribution coefficient based on the theoretical front-rear axle torque distribution adjustment coefficient and the original front-rear axle torque distribution coefficient; After obtaining the theoretical front and rear axle torque distribution adjustment coefficient, further correction is required to combine it with the original front and rear axle torque distribution coefficient according to different conditions to obtain the required final front and rear axle torque distribution coefficient; S6. Distributing the front and rear axle torques of the four-wheel drive vehicle according to the final front and rear axle torque distribution coefficients; The vehicle control system distributes the torque between the front and rear axles according to the final front and rear axle torque distribution coefficient, thereby achieving a high-precision and high-sensitivity control effect.

[0035] In some embodiments of the present application, this embodiment optimizes the above-mentioned step S2. Specifically, the method for correcting the vehicle yaw rate deviation to obtain the final yaw rate deviation is as follows: first, an original yaw rate deviation needs to be obtained. The original yaw rate deviation is obtained based on the actual yaw rate and the target yaw rate. Specifically, the original yaw rate deviation can be obtained as follows: When the actual yaw rate is greater than 0 and the target yaw rate is less than 0, or the actual yaw rate is less than 0 and the target yaw rate is greater than 0, the raw yaw rate deviation is the sum of the absolute value of the actual yaw rate and the absolute value of the target yaw rate. The actual yaw rate can be acquired by the power domain sensor (i.e., the Yaw-G sensor), that is, raw yaw rate deviation = |actual yaw rate| + |target yaw rate|; Otherwise, the original yaw rate deviation is the difference between the absolute value of the actual yaw rate and the absolute value of the target yaw rate, That is, the original yaw rate deviation = |actual yaw rate| - |target yaw rate|.

[0036] After obtaining the original yaw rate deviation, the upper limit and the lower limit of the yaw rate deviation dead zone are determined based on the calibrated steering wheel angle rate, the lateral acceleration absolute value, and the upper limit and the lower limit of the yaw rate deviation dead zone (the yaw rate deviation dead zone is the accuracy interval of the actual yaw rate, which is measured by a sensor, and the dead zone is the accuracy or fluctuation amplitude interval of the sensor). In fact, a two-dimensional table with the steering wheel angle rate as the horizontal coordinate, the lateral acceleration absolute value as the vertical coordinate, and the upper limit of the yaw rate deviation dead zone as the output item, and a two-dimensional table with the steering wheel angle rate as the horizontal coordinate, the lateral acceleration absolute value as the vertical coordinate, and the lower limit of the yaw rate deviation dead zone as the output item are formulated through a large number of calibration tests. In actual application, by calling the corresponding calibration two-dimensional table, the upper limit and the lower limit of the yaw rate deviation dead zone can be obtained by inputting the corresponding steering wheel angle rate (which can be obtained by monitoring the steering wheel sensor) and the lateral acceleration absolute value (which can be obtained by monitoring the dynamic domain sensor). The steering wheel angle rate can be collected by a steering wheel angle sensor, and the lateral acceleration absolute value can be collected by a dynamic domain sensor. The original yaw rate deviation is compared with the upper limit and the lower limit of the yaw rate deviation dead zone. When the original yaw rate deviation is greater than or equal to the upper limit of the yaw rate deviation dead zone, the final yaw rate deviation is the difference between the original yaw rate deviation and the upper limit of the yaw rate deviation dead zone, that is, the final yaw rate deviation = original yaw rate deviation - upper limit of yaw rate deviation dead zone. When the original yaw rate deviation is less than or equal to the lower limit of the yaw rate deviation dead zone, the final yaw rate deviation is the difference between the original yaw rate deviation and the lower limit of the yaw rate deviation dead zone, that is, the final yaw rate deviation = original yaw rate deviation - lower limit of yaw rate deviation dead zone. When the original yaw rate deviation is between the upper limit and the lower limit of the yaw rate deviation dead zone, the final yaw rate deviation is 0.

[0037] According to the above method, the final yaw rate deviation can be obtained.

[0038] The steering wheel angle change rate and the dead zone design are introduced in the final yaw rate deviation calculation. On the one hand, the yaw deviation can be adjusted frequently under the condition that the steering wheel angle change rate is small (such as driving at a small angle on a curved road) (the dead zone of the yaw rate deviation is increased to expand the interval of the final yaw rate deviation, thereby reducing the adjustment frequency), on the other hand, the yaw deviation can be quickly adjusted under the condition that the steering wheel angle change rate is large (such as emergency avoidance) (the dead zone of the yaw rate deviation is reduced to quickly identify the final yaw rate deviation, thereby quickly executing the adjustment).

[0039] In a further embodiment of the present application, the step S3 described above is optimized, and specifically, the method for correcting the actual yaw rate to obtain the actual yaw rate deviation is: obtaining an initial actual yaw rate deviation based on the lateral acceleration, the vehicle speed and the actual yaw rate, specifically, the initial actual yaw rate deviation = lateral acceleration / vehicle speed-actual yaw rate, the lateral acceleration and the vehicle speed are obtained by collecting the dynamic domain sensor; After obtaining the initial reference acceleration, the collected vehicle speed is compared with the set vehicle speed range, and the set vehicle speed range in the present application is 30 km / h-60 km / h, and in actual application, it is not limited to this range. When the vehicle speed is in the set vehicle speed range, the actual yaw rate deviation is the absolute value of the first-order low-pass filtered value of the initial actual yaw rate deviation, and when the vehicle speed is not in the set vehicle speed range, the actual yaw rate deviation is the initial 0.

[0040] According to the above method, the actual yaw rate deviation can be obtained.

[0041] The reason why the actual yaw rate deviation needs to be obtained is that in the conventional control, the actual yaw rate is generally measured by a Yaw-G sensor, but the Yaw-G sensor may have zero drift and other phenomena when driving straight or at low speed, resulting in inaccurate measurement. Therefore, the actual yaw rate deviation parameter is proposed (a theoretical value is calculated based on a simplified steering model at low vehicle speed, and the actual yaw rate deviation is the deviation between the theoretical value and the sensor measured value, i.e., the actual yaw rate), and the actual yaw rate deviation is introduced into the subsequent torque distribution control to improve the accuracy of the yaw control at low speed.

[0042] In a further embodiment of the present application, the step S4 described above is optimized, and specifically, the method for correcting the actual yaw rate deviation and the final yaw rate deviation to obtain the theoretical front-rear axle torque distribution adjustment coefficient is: first, obtaining the vehicle reference acceleration based on the vehicle lateral acceleration and the vehicle longitudinal acceleration, which can be operated according to the following steps: The initial reference acceleration of the current cycle is obtained based on the vehicle's lateral acceleration and longitudinal acceleration. Specifically, the initial reference acceleration = (vehicle lateral acceleration 2 +Vehicle longitudinal acceleration 2 ) 0.5 ; When there is an external torque increase or decrease request (obtained by the vehicle control system), the vehicle reference acceleration = the initial reference acceleration of the current cycle * the first weight coefficient + the reference acceleration of the previous cycle * the second weight coefficient ... the reference acceleration of the previous N-1 cycle * the Nth weight coefficient, and the first weight coefficient + the second weight coefficient ... + the Nth weight coefficient = 1; When there is no external torque increase or decrease request, if the current vehicle speed is greater than the set speed threshold, the vehicle reference acceleration is the larger value of the initial reference acceleration of the current cycle and the reference acceleration of the previous cycle. If the current vehicle speed is not greater than the set speed threshold, the vehicle reference acceleration is the reference acceleration of the previous cycle. When there is an external torque increase or decrease request, the vehicle acceleration will change. However, this torque request is usually short-lived and recovers quickly. At this time, using the estimated vehicle reference acceleration for control will provide smoother control and avoid transient jumps. When there is no external torque increase or decrease request, if the vehicle speed is high, for safety reasons, using the larger of the current cycle initial reference acceleration and the previous cycle reference acceleration as the input variable for control will result in relatively conservative regulation and greater safety. At lower speeds, using the previous cycle reference acceleration as the vehicle reference acceleration for the current cycle will ensure smoother and more stable control. The vehicle speed threshold in this embodiment is set to 40 km / h, but is not limited to this value in actual application.

[0043] After obtaining the vehicle reference acceleration (actually, the vehicle reference acceleration for this cycle), the final front and rear axle torque distribution coefficient adjustment ratio can be obtained based on the actual yaw rate deviation, the vehicle reference acceleration, the driver's required torque, and the absolute value of the lateral acceleration. The specific calculation method can be used as follows: The front-rear axle torque distribution coefficient adjustment ratio term is obtained based on a calibrated two-dimensional table of actual yaw rate deviation, vehicle reference acceleration, and front-rear axle torque distribution coefficient adjustment ratio term. That is, through a large number of standard tests, a two-dimensional table is developed with the actual yaw rate deviation as the abscissa, the vehicle reference acceleration as the ordinate, and the front-rear axle torque distribution coefficient adjustment ratio term as the output term. A two-dimensional table of deviation correction coefficients of the front-rear axle torque distribution coefficient adjustment proportion term based on the calibrated driver demand torque, the final yaw rate deviation, and the front-rear axle torque distribution coefficient adjustment proportion term is obtained, i.e., a two-dimensional table of deviation correction coefficients of the front-rear axle torque distribution coefficient adjustment proportion term with the driver demand torque as the horizontal coordinate, the final yaw rate deviation as the vertical coordinate, and the output term as the front-rear axle torque distribution coefficient adjustment proportion term is produced through a large number of standard tests; A two-dimensional table of acceleration correction coefficients of the front-rear axle torque distribution coefficient adjustment proportion term based on the calibrated driver demand torque, the lateral acceleration absolute value, and the front-rear axle torque distribution coefficient adjustment proportion term is obtained, i.e., a two-dimensional table of acceleration correction coefficients of the front-rear axle torque distribution coefficient adjustment proportion term with the driver demand torque as the horizontal coordinate, the lateral acceleration absolute value as the vertical coordinate, and the output term as the front-rear axle torque distribution coefficient adjustment proportion term is produced through a large number of standard tests; The final front-rear axle torque distribution coefficient adjustment proportion term is the product of the front-rear axle torque distribution coefficient adjustment proportion term, the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment proportion term, and the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment proportion term, i.e., the final front-rear axle torque distribution coefficient adjustment proportion term = front-rear axle torque distribution coefficient adjustment proportion term * deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment proportion term * acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment proportion term.

[0044] The vehicle yaw control enable state is obtained for judgment, when the vehicle yaw control is enabled (i.e., the vehicle control system intervenes in the vehicle yaw control operation), the front-rear axle torque distribution proportion term adjustment coefficient is the product of the final front-rear axle torque distribution coefficient adjustment proportion term and the final yaw rate deviation, i.e., the front-rear axle torque distribution proportion term adjustment coefficient = final front-rear axle torque distribution coefficient adjustment proportion term * final yaw rate deviation; when the vehicle yaw control is not enabled (i.e., the vehicle control system does not intervene in the vehicle yaw control operation), the front-rear axle torque distribution proportion term adjustment coefficient is 0.

[0045] Then, the final front-rear axle torque distribution coefficient adjustment integral term is obtained based on the actual yaw rate deviation, the vehicle reference acceleration, the driver demand torque, and the lateral acceleration absolute value, and the specific operation method is as follows: a two-dimensional table of front-rear axle torque distribution coefficient adjustment integral terms based on the calibrated actual yaw rate deviation, the vehicle reference acceleration, and the front-rear axle torque distribution coefficient adjustment integral term is obtained, i.e., a two-dimensional table of front-rear axle torque distribution coefficient adjustment integral terms with the actual yaw rate deviation as the horizontal coordinate, the vehicle reference acceleration as the vertical coordinate, and the output term as the front-rear axle torque distribution coefficient adjustment integral term is produced through a large number of standard tests; The deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term is obtained based on a two-dimensional table of the calibrated driver demand torque, the final yaw rate deviation, and the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term, i.e., a two-dimensional table of the driver demand torque as the horizontal coordinate, the final yaw rate deviation as the vertical coordinate, and the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term as the output term is made through a large number of standard tests; The acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term is obtained based on a two-dimensional table of the calibrated driver demand torque, the lateral acceleration absolute value, and the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term, i.e., a two-dimensional table of the driver demand torque as the horizontal coordinate, the lateral acceleration absolute value as the vertical coordinate, and the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term as the output term is made through a large number of standard tests; The final front-rear axle torque distribution coefficient adjustment integral term is the product of the front-rear axle torque distribution coefficient adjustment integral term, the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term, and the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term, i.e., the final front-rear axle torque distribution coefficient adjustment integral term = the front-rear axle torque distribution coefficient adjustment integral term * the deviation correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term * the acceleration correction coefficient of the front-rear axle torque distribution coefficient adjustment integral term.

[0046] The front-rear axle torque distribution pre-control adjustment coefficient is obtained based on a two-dimensional table of the calibrated driver demand torque, the lateral acceleration absolute value, and the front-rear axle torque distribution pre-control adjustment coefficient, i.e., a two-dimensional table of the driver demand torque as the horizontal coordinate, the lateral acceleration absolute value as the vertical coordinate, and the front-rear axle torque distribution pre-control adjustment coefficient as the output term is constructed through a large number of calibration tests, and the front-rear axle torque distribution pre-control adjustment coefficient is obtained based on the two-dimensional table; The front-rear axle torque distribution integral term pre-control adjustment coefficient is obtained according to the front-rear axle torque distribution pre-control adjustment coefficient, the original front-rear axle torque distribution coefficient and the front-rear axle torque distribution proportional term adjustment coefficient, and specifically, the front-rear axle torque distribution integral term pre-control adjustment coefficient is the difference between the front-rear axle torque distribution pre-control adjustment coefficient, the original front-rear axle torque distribution coefficient and the front-rear axle torque distribution proportional term adjustment coefficient, that is, the front-rear axle torque distribution integral term pre-control adjustment coefficient = the front-rear axle torque distribution pre-control adjustment coefficient - the original front-rear axle torque distribution coefficient - the front-rear axle torque distribution proportional term adjustment coefficient; the front-rear axle torque distribution integral term adjustment coefficient is continuously accumulated or decreased with the period, and is a long-period response process, relatively speaking; increasing the front-rear axle torque distribution integral term pre-control adjustment coefficient represents that the integral term changes from the front-rear axle torque distribution integral term pre-control adjustment coefficient, which is equivalent to shortening the response period of the front-rear axle torque distribution integral term adjustment coefficient, accelerating the adjustment response, and enabling the control response to be more sensitive; although the front-rear axle torque distribution integral term pre-control adjustment coefficient is used for integral term pre-control, it can accelerate the adjustment response, but excessive integral term pre-control can cause over-response out of control, so the pre-control under different working conditions is limited, and the front-rear axle torque distribution integral term pre-control adjustment coefficient is obtained by subtracting the original front-rear axle torque distribution coefficient and the front-rear axle torque distribution proportional term adjustment coefficient from the front-rear axle torque distribution pre-control adjustment coefficient; The vehicle yaw control enabling state is obtained for judgment, when the vehicle yaw control is switched from being not enabled to being enabled, the front-rear axle torque distribution integral term adjustment coefficient is the front-rear axle torque distribution integral term pre-control adjustment coefficient, that is, the front-rear axle torque distribution integral term adjustment coefficient = the front-rear axle torque distribution integral term pre-control adjustment coefficient; When the vehicle yaw control is enabled, the front-rear axle torque distribution integral term adjustment coefficient is the product of the final front-rear axle torque distribution coefficient adjustment integral term and the final yaw angular velocity deviation, that is, the front-rear axle torque distribution integral term adjustment coefficient = the final front-rear axle torque distribution coefficient adjustment integral term * the final yaw angular velocity deviation; When the vehicle yaw angle control is not enabled, the front-rear axle torque distribution integral term adjustment coefficient is 0.

[0047] After the front-rear axle torque distribution proportional term adjustment coefficient and the front-rear axle torque distribution integral term adjustment coefficient are obtained, the theoretical front-rear axle torque distribution adjustment coefficient of the embodiment is the sum of the front-rear axle torque distribution proportional term adjustment coefficient and the front-rear axle torque distribution integral term adjustment coefficient, that is, the theoretical front-rear axle torque distribution adjustment coefficient = the front-rear axle torque distribution proportional term adjustment coefficient + the front-rear axle torque distribution integral term adjustment coefficient.

[0048] In some embodiments of the present application, the step S5 is optimized, and the method for obtaining the final front-rear axle torque distribution coefficient based on the theoretical front-rear axle torque distribution adjustment coefficient and the original front-rear axle torque distribution coefficient is as follows: the theoretical front-rear axle torque distribution adjustment coefficient is corrected to obtain the limited front-rear axle torque distribution adjustment coefficient. The specific operation method is as follows: the upper limit of the theoretical front-rear axle torque distribution coefficient and the lower limit of the theoretical front-rear axle torque distribution coefficient are obtained based on the calibrated vehicle reference acceleration, the driver demand torque, the upper limit of the theoretical front-rear axle torque distribution coefficient and the lower limit of the theoretical front-rear axle torque distribution coefficient two-dimensional table, that is, through a large number of calibration tests, a two-dimensional table with the vehicle reference acceleration as the horizontal coordinate, the driver demand torque as the vertical coordinate, and the upper limit of the theoretical front-rear axle torque distribution coefficient as the output item, and a two-dimensional table with the vehicle reference acceleration as the horizontal coordinate, the driver demand torque as the vertical coordinate, and the lower limit of the theoretical front-rear axle torque distribution coefficient as the output item are constructed. The upper limit of the theoretical front-rear axle torque distribution coefficient and the lower limit of the theoretical front-rear axle torque distribution coefficient can be obtained through the above two calibration two-dimensional tables. The original front-rear axle torque distribution coefficient is compared with the upper and lower limits of the theoretical front-rear axle torque distribution coefficient. When the difference between the lower limit of the theoretical front-rear axle torque distribution coefficient and the original front-rear axle torque distribution coefficient ≤ the theoretical front-rear axle torque distribution coefficient ≤ the difference between the upper limit of the theoretical front-rear axle torque distribution coefficient and the original front-rear axle torque distribution coefficient, that is, the lower limit of the theoretical front-rear axle torque distribution coefficient - the original front-rear axle torque distribution coefficient ≤ the theoretical front-rear axle torque distribution coefficient ≤ the upper limit of the theoretical front-rear axle torque distribution coefficient - the original front-rear axle torque distribution coefficient, the theoretical front-rear axle torque distribution coefficient is taken as the limited front-rear axle torque distribution adjustment coefficient. When the theoretical front-rear axle torque distribution coefficient < the difference between the lower limit of the theoretical front-rear axle torque distribution coefficient and the original front-rear axle torque distribution coefficient, that is, the theoretical front-rear axle torque distribution coefficient < the lower limit of the theoretical front-rear axle torque distribution coefficient - the original front-rear axle torque distribution coefficient, the difference between the lower limit of the theoretical front-rear axle torque distribution coefficient and the original front-rear axle torque distribution coefficient is taken as the limited front-rear axle torque distribution adjustment coefficient, that is, the limited front-rear axle torque distribution adjustment coefficient = the lower limit of the theoretical front-rear axle torque distribution coefficient - the original front-rear axle torque distribution coefficient. When the theoretical front-rear axle torque distribution coefficient > the difference between the lower limit of the theoretical front-rear axle torque distribution coefficient and the original front-rear axle torque distribution coefficient, that is, the theoretical front-rear axle torque distribution coefficient > the lower limit of the theoretical front-rear axle torque distribution coefficient - the original front-rear axle torque distribution coefficient, the difference between the upper limit of the theoretical front-rear axle torque distribution coefficient and the original front-rear axle torque distribution coefficient is taken as the limited front-rear axle torque distribution adjustment coefficient, that is, the limited front-rear axle torque distribution adjustment coefficient = the upper limit of the theoretical front-rear axle torque distribution coefficient - the original front-rear axle torque distribution coefficient.

[0049] The limited front-rear axle torque distribution adjustment coefficient is obtained, and a sum of the limited front-rear axle torque distribution adjustment coefficient and an original front-rear axle torque distribution coefficient is taken as a final front-rear axle torque distribution coefficient, i.e., the final front-rear axle torque distribution coefficient = the limited front-rear axle torque distribution adjustment coefficient + the original front-rear axle torque distribution coefficient.

[0050] After the final front-rear axle torque distribution coefficient is obtained, the control system can adjust and distribute the front-rear axle torque according to the final front-rear axle torque distribution coefficient.

[0051] By designing the upper limit and the lower limit of the theoretical front-rear axle torque distribution coefficient based on the vehicle reference acceleration and the driver demand torque, different adjustment intensities can be limited in different states, and the safety boundary can be ensured, for example, the adjustment intensity is appropriately low in the case of large throttle quick acceleration to avoid over-response and loss of control.

[0052] In actual application, in addition to the above control method, or in other words, the above control method is a control strategy based on the TCS not being actuated, when the TCS is actuated, the final front-rear axle torque distribution coefficient is limited from changing, i.e., the final front-rear axle torque distribution coefficient in the current period is equal to the final front-rear axle torque distribution coefficient in the last period, and the front-rear axle torque distribution proportional term adjustment coefficient and the front-rear axle torque distribution integral term adjustment coefficient are also equal to the values in the last period.

[0053] When the TCS is actuated, the actual power torque and the TCS torque act on the vehicle, and in this process, the power torque (the final front-rear axle torque distribution coefficient) is controlled to be maintained to ensure smooth TCS control and avoid mismatch or affect the TCS control effect caused by simultaneous adjustment.

[0054] In addition, the application also relates to a control system, the control system according to the above control method, and the control system comprising a first correction module, a second correction module, a third correction module, a distribution coefficient determination module and an execution module, the first correction module is used for correcting a vehicle yaw rate deviation to obtain a final yaw rate deviation; the second correction module is used for correcting an actual yaw rate to obtain an actual yaw rate deviation; the third correction module is used for correcting an original front-rear axle torque distribution coefficient based on the actual yaw rate deviation and the final yaw rate deviation to obtain a theoretical front-rear axle torque distribution adjustment coefficient; the distribution coefficient determination module is used for obtaining a final front-rear axle torque distribution coefficient based on the theoretical front-rear axle torque distribution adjustment coefficient and the original front-rear axle torque distribution coefficient; and the execution module is used for distributing the front-rear axle torque of the four-wheel drive vehicle according to the final front-rear axle torque distribution coefficient.

[0055] In addition, the control system of the present application further includes a collection module and an acquisition module, wherein the collection module is used to collect the actual yaw rate of the vehicle; the acquisition module is used to obtain the vehicle yaw rate deviation and the original front and rear axle torque distribution coefficient.

[0056] The present application provides a computer-readable storage medium having computer-readable program instructions (i.e., computer program) stored thereon, and the computer-readable program instructions are used to execute a method for controlling the front and rear axle torque distribution of a four-wheel drive vehicle in the above-mentioned embodiment.

[0057] 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, systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium that contains or stores 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 appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0058] The computer-readable storage medium may be included in the range-extended electric vehicle control device; or may exist independently without being assembled into the range-extended electric vehicle control device.

[0059] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by a front and rear axle torque distribution control system of a four-wheel drive vehicle, the front and rear axle torque distribution control system of the four-wheel drive vehicle: when the four-wheel drive vehicle turns, the actual yaw velocity of the vehicle is collected, and the vehicle yaw velocity deviation and the original front and rear axle torque distribution coefficient are obtained; the vehicle yaw velocity deviation is corrected to obtain a final yaw velocity deviation; the actual yaw velocity is corrected to obtain an actual yaw velocity deviation; based on the actual yaw velocity deviation and the final yaw velocity deviation, the original front and rear axle torque distribution coefficient is corrected to obtain a theoretical front and rear axle torque distribution adjustment coefficient; based on the theoretical front and rear axle torque distribution adjustment coefficient and the original front and rear axle torque distribution coefficient, a final front and rear axle torque distribution coefficient is obtained; and the front and rear axle torque of the four-wheel drive vehicle is distributed according to the final front and rear axle torque distribution coefficient.

[0060] Computer program code for carrying out the operations of the present application may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server.

[0061] Where a remote computer is involved, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or it may be connected to an external computer (for example, through the Internet using an Internet service provider).

[0062] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, program segment or a part of code, and the module, program segment or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0063] The modules described in the embodiments of the present application may be implemented in software or hardware, wherein the name of a module does not necessarily limit the unit itself.

[0064] The computer-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 extended-range electric vehicle control method, thereby resolving the technical problem. Compared to the prior art, the beneficial effects of the computer-readable storage medium provided in this application are similar to those of the aforementioned embodiment of a four-wheel drive vehicle front and rear axle torque distribution control method, and are not further elaborated here.

[0065] The present application also provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for controlling the torque distribution between front and rear axles of a four-wheel drive vehicle.

[0066] The computer program product provided in this application can solve technical problems. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the method for controlling the torque distribution between the front and rear axles of a four-wheel drive vehicle provided in the above embodiment, and will not be elaborated here.

[0067] The above shows and describes the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in this application is defined by the appended claims and their equivalents.

Claims

1. A method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle, characterized by: include, When the four-wheel drive vehicle turns, the actual yaw rate of the vehicle is collected, and the vehicle yaw rate deviation and the original front and rear axle torque distribution coefficient are obtained; Correcting the vehicle yaw rate deviation to obtain a final yaw rate deviation; Correcting the actual yaw rate to obtain an actual yaw rate deviation; Based on the actual yaw rate deviation and the final yaw rate deviation, the original front and rear axle torque distribution coefficient is corrected to obtain the theoretical front and rear axle torque distribution adjustment coefficient; Obtaining a final front-to-rear axle torque distribution coefficient based on a theoretical front-to-rear axle torque distribution adjustment coefficient and an original front-to-rear axle torque distribution coefficient; The front and rear axle torque of the four-wheel drive vehicle is distributed according to the final front and rear axle torque distribution coefficient.

2. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 1, wherein: The method for obtaining the final front-rear axle torque distribution coefficient based on the theoretical front-rear axle torque distribution adjustment coefficient and the original front-rear axle torque distribution coefficient includes: correcting the theoretical front-rear axle torque distribution adjustment coefficient to obtain the restricted rear front-rear axle torque distribution adjustment coefficient; and taking the sum of the restricted rear front-rear axle torque distribution adjustment coefficient and the original front-rear axle torque distribution coefficient as the final front-rear axle torque distribution coefficient.

3. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 2, wherein: The method for correcting the theoretical front-to-rear axle torque distribution adjustment coefficient to obtain the limited front-to-rear axle torque distribution adjustment coefficient includes: obtaining the theoretical front-to-rear axle torque distribution coefficient upper limit and the theoretical front-to-rear axle torque distribution coefficient lower limit based on a calibrated vehicle reference acceleration, a driver's required torque, and a two-dimensional table of theoretical front-to-rear axle torque distribution coefficient upper limits and lower limits; When the difference between the lower limit of the theoretical front-to-rear axle torque distribution coefficient and the original front-to-rear axle torque distribution coefficient is less than or equal to the theoretical front-to-rear axle torque distribution coefficient and less than or equal to the difference between the upper limit of the theoretical front-to-rear axle torque distribution coefficient and the original front-to-rear axle torque distribution coefficient, the theoretical front-to-rear axle torque distribution coefficient is used as the rear-rear axle torque distribution adjustment coefficient; When the theoretical front-to-rear axle torque distribution coefficient is less than the difference between the lower limit of the theoretical front-to-rear axle torque distribution coefficient and the original front-to-rear axle torque distribution coefficient, the difference between the lower limit of the theoretical front-to-rear axle torque distribution coefficient and the original front-to-rear axle torque distribution coefficient is used as the rear-rear axle torque distribution adjustment coefficient; When the theoretical front-rear axle torque distribution coefficient is greater than the difference between the lower limit of the theoretical front-rear axle torque distribution coefficient and the original front-rear axle torque distribution coefficient, the difference between the upper limit of the theoretical front-rear axle torque distribution coefficient and the original front-rear axle torque distribution coefficient is used as the rear-rear axle torque distribution adjustment coefficient.

4. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 1, wherein: The method for correcting the original front-to-rear axle torque distribution coefficient based on the actual yaw rate deviation and the final yaw rate deviation to obtain the theoretical front-to-rear axle torque distribution adjustment coefficient includes: obtaining a vehicle reference acceleration based on the vehicle lateral acceleration and the vehicle longitudinal acceleration; obtaining a final front-to-rear axle torque distribution coefficient adjustment proportional term and a final front-to-rear axle torque distribution coefficient adjustment integral term based on the actual yaw rate deviation, the vehicle reference acceleration, the driver's required torque, and the absolute value of the lateral acceleration; Obtaining a vehicle yaw control enable state for determination, adjusting the proportional term based on the absolute value of the lateral acceleration and the final front and rear axle torque distribution coefficient according to the vehicle yaw control enable state to obtain a front and rear axle torque distribution proportional term adjustment coefficient, and adjusting the integral term based on the vehicle yaw control enable state and the final front and rear axle torque distribution coefficient to obtain a front and rear axle torque distribution integral term adjustment coefficient; The sum of the front-rear axle torque distribution proportional item adjustment coefficient and the front-rear axle torque distribution integral item adjustment coefficient is used as the theoretical front-rear axle torque distribution adjustment coefficient.

5. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 4, wherein: The method for obtaining the front-rear axle torque distribution proportional term adjustment coefficient based on the absolute value of the lateral acceleration and the final front-rear axle torque distribution coefficient adjustment proportional term according to the vehicle yaw control enable state includes: when the vehicle yaw control is enabled, the front-rear axle torque distribution proportional term adjustment coefficient is the product of the final front-rear axle torque distribution coefficient adjustment proportional term and the final yaw angular velocity deviation; When the vehicle yaw angle control is not enabled, the front and rear axle torque distribution ratio adjustment coefficient is 0.

6. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 5, wherein: The method for obtaining a front-to-rear axle torque distribution integral item adjustment coefficient based on the vehicle yaw control enable state and the final front-to-rear axle torque distribution coefficient adjustment integral item includes: obtaining the front-to-rear axle torque distribution pre-control adjustment coefficient based on a calibrated two-dimensional table of driver demand torque, lateral acceleration absolute value, and front-to-rear axle torque distribution pre-control adjustment coefficient; obtaining the front-to-rear axle torque distribution integral item adjustment coefficient based on the front-to-rear axle torque distribution pre-control adjustment coefficient, the original front-to-rear axle torque distribution coefficient, and the front-to-rear axle torque distribution proportional item adjustment coefficient; When the vehicle yaw control is switched from unenabled to enabled, the front and rear axle torque distribution integral term adjustment coefficient is the front and rear axle torque distribution integral term pre-control adjustment coefficient; When vehicle yaw control is enabled, the front and rear axle torque distribution integral term adjustment coefficient is the product of the final front and rear axle torque distribution coefficient adjustment integral term and the final yaw rate deviation; When the vehicle yaw angle control is not enabled, the front and rear axle torque distribution integral adjustment coefficient is 0.

7. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 6, wherein: The method for obtaining the front and rear axle torque distribution integral item pre-control adjustment coefficient based on the front and rear axle torque distribution pre-control adjustment coefficient, the original front and rear axle torque distribution coefficient and the front and rear axle torque distribution proportional item adjustment coefficient includes: the front and rear axle torque distribution integral item pre-control adjustment coefficient is the difference between the front and rear axle torque distribution pre-control adjustment coefficient, the original front and rear axle torque distribution coefficient and the front and rear axle torque distribution proportional item adjustment coefficient.

8. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 4, wherein: The method for obtaining a final front-to-rear axle torque distribution coefficient adjustment proportional term based on an actual yaw rate deviation, a vehicle reference acceleration, a driver demand torque, and an absolute value of a lateral acceleration includes: obtaining the front-to-rear axle torque distribution coefficient adjustment proportional term based on a calibrated two-dimensional table of actual yaw rate deviation, vehicle reference acceleration, and front-to-rear axle torque distribution coefficient adjustment proportional term; obtaining a deviation correction coefficient for the front-to-rear axle torque distribution coefficient adjustment proportional term based on a calibrated two-dimensional table of driver demand torque, final yaw rate deviation, and deviation correction coefficients for the front-to-rear axle torque distribution coefficient adjustment proportional term; and obtaining an acceleration correction coefficient for the front-to-rear axle torque distribution coefficient adjustment proportional term based on a calibrated two-dimensional table of driver demand torque, an absolute value of a lateral acceleration, and acceleration correction coefficients for the front-to-rear axle torque distribution coefficient adjustment proportional term. The final front and rear axle torque distribution coefficient adjustment proportional term is the product of the front and rear axle torque distribution coefficient adjustment proportional term, the deviation correction coefficient of the front and rear axle torque distribution coefficient adjustment proportional term, and the acceleration correction coefficient of the front and rear axle torque distribution coefficient adjustment proportional term.

9. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 4, wherein: The method for obtaining a final front-to-rear axle torque distribution coefficient adjustment integral term based on an actual yaw rate deviation, a vehicle reference acceleration, a driver demand torque, and an absolute value of a lateral acceleration includes: obtaining the front-to-rear axle torque distribution coefficient adjustment integral term based on a calibrated two-dimensional table of actual yaw rate deviation, vehicle reference acceleration, and front-to-rear axle torque distribution coefficient adjustment integral term; obtaining a deviation correction coefficient for the front-to-rear axle torque distribution coefficient adjustment integral term based on a calibrated two-dimensional table of driver demand torque, final yaw rate deviation, and deviation correction coefficients for the front-to-rear axle torque distribution coefficient adjustment integral term; and obtaining an acceleration correction coefficient for the front-to-rear axle torque distribution coefficient adjustment integral term based on a calibrated two-dimensional table of driver demand torque, an absolute value of a lateral acceleration, and acceleration correction coefficients for the front-to-rear axle torque distribution coefficient adjustment integral term. The final front and rear axle torque distribution coefficient adjustment integral term is the product of the front and rear axle torque distribution coefficient adjustment integral term, the deviation correction coefficient of the front and rear axle torque distribution coefficient adjustment integral term, and the acceleration correction coefficient of the front and rear axle torque distribution coefficient adjustment integral term.

10. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 4, wherein: The method for obtaining a vehicle reference acceleration based on the vehicle lateral acceleration and the vehicle longitudinal acceleration includes: obtaining a current cycle initial reference acceleration based on the vehicle lateral acceleration and the vehicle longitudinal acceleration; When there is an external torque increase or decrease request, the vehicle reference acceleration = the initial reference acceleration of the current cycle * the first weight coefficient + the reference acceleration of the previous cycle * the second weight coefficient ... the reference acceleration of the previous N-1 cycle * the Nth weight coefficient, and the first weight coefficient + the second weight coefficient ... + the Nth weight coefficient = 1; When there is no external torque increase or decrease request, if the current vehicle speed is greater than the set speed threshold, the vehicle reference acceleration is the larger value of the initial reference acceleration of the current cycle and the reference acceleration of the previous cycle. If the current vehicle speed is not greater than the set speed threshold, the vehicle reference acceleration is the reference acceleration of the previous cycle.

11. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 1, wherein: The method for correcting the vehicle yaw rate deviation to obtain a final yaw rate deviation includes: obtaining an original yaw rate deviation based on an actual yaw rate and a target yaw rate; determining an upper limit of a yaw rate deviation dead zone and a lower limit of a yaw rate deviation dead zone based on a calibrated steering wheel angle change rate, an absolute value of a lateral acceleration, and an upper limit and a lower limit of a yaw rate deviation dead zone; When the original yaw rate deviation is greater than or equal to the upper limit of the yaw rate deviation dead zone, the final yaw rate deviation is the difference between the original yaw rate deviation and the upper limit of the yaw rate deviation dead zone; When the original yaw rate deviation is less than or equal to the lower limit of the yaw rate deviation dead zone, the final yaw rate deviation is the difference between the original yaw rate deviation and the lower limit of the yaw rate deviation dead zone; When the original yaw rate deviation is between the upper limit of the yaw rate deviation dead zone and the lower limit of the yaw rate deviation dead zone, the final yaw rate deviation is 0.

12. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 11, wherein: The method for obtaining a raw yaw rate deviation based on an actual yaw rate and a target yaw rate includes: when the actual yaw rate is greater than 0 and the target yaw rate is less than 0, or the actual yaw rate is less than 0 and the target yaw rate is greater than 0, the raw yaw rate deviation is the sum of the absolute value of the actual yaw rate and the absolute value of the target yaw rate; otherwise, the raw yaw rate deviation is the difference between the absolute value of the actual yaw rate and the absolute value of the target yaw rate.

13. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 11, wherein: The method for correcting the actual yaw rate to obtain an actual yaw rate deviation includes: obtaining an initial actual yaw rate deviation based on a lateral acceleration, a vehicle speed, and an actual yaw rate; when the vehicle speed is within a set speed range, the actual yaw rate deviation is an absolute value of a first-order low-pass filtered value of the initial actual yaw rate deviation; when the vehicle speed is not within the set speed range, the actual yaw rate deviation is initially zero.

14. The method for controlling torque distribution between front and rear axles of a four-wheel drive vehicle according to claim 1, wherein: When TCS is activated, the final front and rear axle torque distribution coefficient of this cycle is the final front and rear axle torque distribution coefficient of the previous cycle.

15. A control system, characterized in that: include, a first correction module, configured to correct the vehicle yaw rate deviation to obtain a final yaw rate deviation; a second correction module, configured to correct the actual yaw rate to obtain an actual yaw rate deviation; a third correction module, which corrects the original front-rear axle torque distribution coefficient based on the actual yaw rate deviation and the final yaw rate deviation to obtain a theoretical front-rear axle torque distribution adjustment coefficient; a distribution coefficient determination module, the distribution coefficient determination module obtaining a final front and rear axle torque distribution coefficient based on a theoretical front and rear axle torque distribution adjustment coefficient and an original front and rear axle torque distribution coefficient; An execution module distributes the front and rear axle torques of the four-wheel drive vehicle according to a final front and rear axle torque distribution coefficient.

16. A control system according to claim 15, characterized in that: Also includes, An acquisition module, wherein the acquisition module is used to acquire the actual yaw angular velocity of the vehicle; The acquisition module is used to obtain the vehicle yaw rate deviation and the original front and rear axle torque distribution coefficient.

17. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for controlling the torque distribution between the front and rear axles of a four-wheel drive vehicle as described in any one of claims 1 to 14 are implemented.

18. A computer program product, characterized in that The computer program product includes a computer program, and when the computer program is executed by a processor, the steps of the front and rear axle torque distribution control method of a four-wheel drive vehicle as described in any one of claims 1 to 14 are implemented.

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