Electric vehicle drive control method, device, computer equipment and storage medium

Abstract

The present application relates to a drive control method, device, computer equipment and storage medium for an electric vehicle, the method comprising determining the adhesion state of the front axle wheels and the rear axle wheels; when the adhesion states of the front axle wheels and the rear axle wheels are both in stable state, determining a correction parameter from a preset first mapping relationship according to the vehicle speed, steering wheel angle and body yaw angular velocity, and when the correction parameter is less than a first threshold value, determining that the rear axle of the vehicle is a drive axle; when the correction parameter is greater than or equal to the first threshold value, determining that the front axle and rear axle of the vehicle are both drive axles, and determining a first transfer ratio of the front axle from a preset second mapping relationship according to the correction parameter, transferring the required torque to the front axle according to the first transfer ratio to switch from rear-wheel drive control to four-wheel drive control. The method of the present application is used to improve the problem in the prior art that torque distribution of electric vehicles cannot be flexibly controlled.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a method, device, computer equipment, and storage medium for driving control of an electric vehicle. Background Art

[0002] Electric vehicles achieve four-wheel drive by arranging drive motors on the front and rear axles. Compared with two-wheel drive models, four-wheel drive models can provide stronger traction and passing performance, especially in harsh road conditions. Currently, the torque distribution method of four-wheel drive vehicles mostly distributes the driving force to the front and rear wheels in a constant ratio, such as 40:60. This method can provide continuous four-wheel drive performance. Regardless of road conditions, the driving torque will be evenly transmitted to the front and rear wheels; however, under some working conditions, four-wheel drive is not required, and the four-wheel drive mode will result in a waste of efficiency.

[0003] Therefore, the constant ratio torque distribution method cannot meet the driving requirements under different working conditions and cannot fully exert the performance of the vehicle. Summary of the Invention

[0004] Based on this, a method, device, computer equipment and storage medium for controlling electric vehicle driving are provided to improve the problem in the prior art that torque distribution of electric vehicles cannot be flexibly controlled.

[0005] In one aspect, a method for controlling a driving of an electric vehicle is provided, the method comprising:

[0006] determining the adhesion states of the front and rear axle wheels according to wheel state parameters, wherein the wheel state parameters include the wheel speed change rate and wheel speed difference of each wheel, and the adhesion states include a stable state and a slipping state;

[0007] When the adhesion states of the front axle wheels and the rear axle wheels are both in stable states, determining a correction parameter from a preset first mapping relationship according to the vehicle speed, the steering wheel angle, and the vehicle body yaw rate, wherein the correction parameter is positively correlated with the vehicle speed, the steering wheel angle, and the vehicle body yaw rate in the mapping relationship;

[0008] Determine drive shaft and actuation torque, including:

[0009] When the correction parameter is less than a first threshold, the rear axle of the vehicle is determined to be the drive axle, and the required torque of the vehicle is determined to be the execution torque of the drive axle to perform rear-wheel drive control; or

[0010] When the correction parameter is greater than or equal to the first threshold value, it is determined that the front axle and the rear axle of the vehicle are both drive axles, and based on the correction parameter, the first transfer ratio of the front axle is determined from a preset second mapping relationship, the required torque is transferred to the front axle according to the first transfer ratio, and the execution torque of the front axle and the execution torque of the rear axle are determined respectively to switch from rear-wheel drive control to four-wheel drive control.

[0011] In one embodiment, after determining the adhesion states of the front axle wheels and the rear axle wheels according to the wheel state parameters, the method further includes:

[0012] When the adhesion state of the front axle wheels or the rear axle wheels is a stable state and the adhesion state of the other axle is a slipping state, the axle with the stable adhesion state is determined to be the driving axle, and the required torque is determined to be the execution torque of the driving axle.

[0013] In one embodiment, after determining the adhesion states of the front axle wheels and the rear axle wheels according to the wheel state parameters, the method further includes:

[0014] When the adhesion states of the front axle wheels and the rear axle wheels are both in a slip state, it is determined that the front axle and the rear axle of the vehicle are both drive axles, and the execution torque of the front axle and the rear axle is determined according to a preset transfer ratio to perform four-wheel drive control.

[0015] In one embodiment, determining the torque transfer ratio of the front axle from the preset second mapping relationship further includes:

[0016] When the correction parameter is greater than a second threshold, the first transfer ratio is increased to obtain a second transfer ratio, so as to determine the execution torque of the front axle and the execution torque of the rear axle respectively according to the second transfer ratio, wherein the second threshold is greater than the first threshold.

[0017] In one embodiment, after determining the drive shaft and executing the torque, the method further includes:

[0018] Get the wheel adhesion of the front and rear axles;

[0019] determining the torque extremes of the front axle and the rear axle respectively according to the wheel adhesion of the front axle and the rear axle;

[0020] When the execution torque of the drive shaft is greater than or equal to the torque limit, the execution torque is limited according to the torque limit, so as to perform rear-wheel drive control or four-wheel drive control according to the limited execution torque.

[0021] In one embodiment, determining the adhesion states of the front and rear axles of the wheels according to the wheel state parameters includes:

[0022] determining the adhesion state based on a comparison result of the wheel speed change rate and the change rate threshold, and a comparison result of a first wheel speed difference and the wheel speed difference threshold, wherein the first wheel speed difference is a maximum value among the wheel speed differences;

[0023] When the wheel speed change rate is less than a change rate threshold, and the first wheel speed difference is less than a wheel speed difference threshold, it is determined that both the front axle and the rear axle are in a stable state.

[0024] In one embodiment, determining the adhesion states of the front and rear axles of the wheels according to the wheel state parameters further includes:

[0025] determining the adhesion state of the front axle based on a comparison result of the wheel speed change rate of the front axle wheels with a change rate threshold, or a comparison result of a second wheel speed difference with the wheel speed difference threshold, wherein the second wheel speed difference is obtained by a difference between a maximum wheel speed of the front axle wheels and a minimum wheel speed of the rear axle wheels;

[0026] If the wheel speed change rate of the front axle wheel is greater than or equal to the change rate threshold, or the second wheel speed difference is greater than or equal to the wheel speed difference threshold, it is determined that the front axle is in a slip state;

[0027] determining the adhesion state of the rear axle based on a comparison result of the wheel speed change rate of the rear axle wheels with a change rate threshold, or a comparison result of a third wheel speed difference with the wheel speed difference threshold, wherein the third wheel speed difference is obtained based on a difference between a maximum wheel speed of the rear axle wheels and a minimum wheel speed of the front axle wheels;

[0028] When the wheel speed change rate of the rear axle wheels is greater than or equal to the change rate threshold, or the third wheel speed difference is greater than or equal to the wheel speed difference threshold, it is determined that the rear axle is in a slip state.

[0029] In another aspect, a driving control device for an electric vehicle is provided, the device comprising:

[0030] The monitoring module is used to determine the adhesion state of the front axle wheels and the rear axle wheels based on the wheel state parameters, wherein the wheel state parameters include the wheel speed change rate and the wheel speed difference of each wheel, and the adhesion state includes a stable state and a slip state.

[0031] a calculation module, configured to determine, when the adhesion states of the front axle wheels and the rear axle wheels are both in a stable state, a correction parameter from a preset first mapping relationship based on the vehicle speed, the steering wheel angle, and the vehicle body yaw rate, wherein in the mapping relationship, the correction parameter is positively correlated with the vehicle speed, the steering wheel angle, and the vehicle body yaw rate;

[0032] An execution module is used to determine the drive shaft and the execution torque, including when the correction parameter is less than a first threshold, determining that the rear axle of the vehicle is the drive shaft, and determining the required torque of the vehicle as the execution torque of the drive shaft to perform rear-wheel drive control; or when the correction parameter is greater than or equal to the first threshold, determining that the front axle and rear axle of the vehicle are both drive shafts, and according to the correction parameter, determining a first transfer ratio of the front axle from a preset second mapping relationship, transferring the required torque to the front axle according to the first transfer ratio, and respectively determining the execution torque of the front axle and the execution torque of the rear axle to switch from rear-wheel drive control to four-wheel drive control.

[0033] In another aspect, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the steps of the method are implemented when the processor executes the computer program.

[0034] A computer-readable storage medium is also provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method are implemented.

[0035] The above-mentioned electric vehicle drive control method, device, computer equipment and storage medium determine the adhesion status of the front axle wheels and the rear axle wheels through wheel state parameters, and thereby determine whether the vehicle is in a stable state. When the vehicle is in a stable state, correction parameters reflecting the vehicle's lateral stability and the intensity of the vehicle body deflection are determined based on the vehicle's speed, steering wheel angle and body yaw angular velocity. When the correction parameter is less than a first threshold, it is considered that the vehicle is in a straight line driving at a low speed. At this time, the rear-wheel drive mode is adopted, which is conducive to the rear wheel adhesion; when the correction parameter reaches or even exceeds the first threshold, it switches to four-wheel drive control to effectively improve driving stability. The above-mentioned method adopts different torque distribution methods under different driving conditions to maximize the driving performance of the four-wheel drive vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 1 is a flow chart of a driving control method for an electric vehicle according to an embodiment;

[0037] Figure 2 Schematic diagram of mapping between correction parameters and transfer coefficients in one embodiment;

[0038] Figure 3 is a dynamic model of a vehicle in one embodiment;

[0039] Figure 4 This is a structural block diagram of an electric vehicle drive control device in one embodiment;

[0040] Figure 5 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0042] Electric four-wheel drive vehicles are often driven by dual front and rear motors. Unlike fuel vehicles, they do not need to consider traditional axle length, transfer case, differential lock layout and other issues, so the implementation cost is lower.

[0043] Currently, most electric four-wheel drive vehicles use a fixed ratio method for front and rear torque distribution. However, due to the large torque and quick response of the drive motor, if the front and rear motor torque is not properly distributed during starting acceleration, uphill starting and other working conditions, wheel slippage is often likely to occur, resulting in a slower starting response. In severe cases, there are safety hazards such as vehicle instability.

[0044] This application provides a method for controlling electric vehicle driving. Figure 1 As shown, the following steps are included:

[0045] Step 101: Determine the adhesion states of the front axle wheels and the rear axle wheels according to the wheel state parameters.

[0046] The front axle and rear axle of a vehicle are also commonly referred to as the front axle assembly, rear axle assembly, front axle, and rear axle. Electric vehicles are equipped with drive motors on the front axle and rear axle respectively to drive the front wheels and rear wheels.

[0047] In this embodiment, the wheel state parameters include the wheel speed change rate and wheel speed difference of each wheel. The vehicle controller monitors the wheel speed v of each wheel in real time. wheel_i (i represents each wheel of the vehicle, including the right front wheel FR, the left front wheel FL, the right rear wheel RR, and the left rear wheel RL), and the wheel speed change rate v' of each wheel over time is obtained based on the wheel speed wheel_i On the other hand, the wheel speed difference between each wheel is obtained based on the wheel speed. Generally, when the vehicle wheels are not slipping, the wheel speed change rate and the wheel speed difference are both within a certain range. Therefore, based on the comparison between the wheel speed change rate and the wheel speed difference and the preset conditions, it can be determined whether the vehicle is in a stable state or a slipping state.

[0048] For example, the attachment status is determined as follows:

[0049] For the stable state, the wheel state parameters are kept in a certain range, namely:

[0050]

[0051] In the above mathematical expression, a thd 、v thdThey are the change rate threshold and wheel speed difference threshold, both of which can be determined by calibration. is the maximum value of the wheel speed, min(v wheel_i ) is the minimum value of the wheel speed, and the maximum wheel speed difference is calculated from the difference between the two.

[0052] If the above conditions are met, it can be considered that the front and rear axles of the vehicle are in a stable state, and it can be understood that the wheel speed change rate v' wheel_i Mainly consider the wheel acceleration state.

[0053] For the slip state, when the above mathematical expression is not satisfied, it can be considered that the vehicle is skidding.

[0054] The driving control method provided in this embodiment can provide driving torque transfer in a stable state to meet the needs of different scenarios and maximize the use of vehicle efficiency. Therefore, the next step is implemented when both the front and rear axles are in a stable state.

[0055] Step 102 : determining a correction parameter from a preset first mapping relationship according to the vehicle speed, the steering wheel angle, and the vehicle body yaw rate.

[0056] The vehicle speed is the longitudinal speed v of the vehicle along the direction of the vehicle body. long The steering wheel angle θ can be obtained through sensor detection. The body yaw rate ω refers to the speed at which the car body swings laterally during driving, which can also be obtained through sensor elements. It is worth mentioning that the steering wheel angle and the body yaw rate are both scalar values, and the direction of rotation or swinging can be ignored.

[0057] Exemplarily illustrate the first mapping relationship It can be stored in the form of a mapping table on the vehicle side. In the first mapping relationship, the correction parameter With vehicle speed v long It is a positive correlation. Under the condition of limiting other conditions, the higher the vehicle speed, the larger the correction parameter; the correction parameter It is positively correlated with the steering wheel angle θ. The larger the steering wheel angle, the larger the correction parameter. It is also positively correlated with the vehicle body yaw angular velocity ω. The greater the vehicle body yaw angular velocity, the larger the correction parameter.

[0058] The magnitude of the correction parameter can reflect the intensity of the vehicle's motion, and has a larger value when the vehicle is at high speed or making a sharp turn.

[0059] Step 103 : Determine the driving shaft and execution torque of the vehicle based on the correction parameters.

[0060] In this embodiment, the vehicle has the rear axle as the main axle, the rear axle is driven by a drive motor with better performance, and the drive motor of the front axle is used for auxiliary purpose.

[0061] As mentioned above, the larger the correction parameter, the higher the vehicle speed or the greater the rotation and yaw. In this embodiment, the first threshold value of the correction parameter is determined through experimental calibration. When the correction parameter is greater than or equal to the first threshold value, it is determined that the front and rear axles of the vehicle are both drive axles, and four-wheel drive is performed to improve the stability of the vehicle.

[0062] When the correction parameter is less than the first threshold, it is determined that the vehicle is basically in a straight and low-speed driving condition, such as a typical vehicle starting scenario. At this time, determining that the rear axle of the vehicle is the drive axle can still meet the driving needs. Moreover, at low speeds, most vehicles have an acceleration trend. When accelerating, the center of gravity of the vehicle moves rearward, and the rear wheels have greater adhesion. The use of rear-wheel drive can provide better driving stability and comfort. After accelerating to a certain extent, as the correction parameter increases to the first threshold, the vehicle switches to four-wheel drive control to improve high-speed driving performance or steering performance.

[0063] When driving with rear-wheel drive, the vehicle's required torque is the execution torque of the drive shaft. When driving with four-wheel drive, the torque is distributed proportionally, and part of the torque is transferred from the rear-wheel drive to the front-wheel drive.

[0064] In this embodiment, based on the correction parameter, the first transfer ratio of the front axle is determined from the preset second mapping relationship, the required torque is transferred to the front axle according to the first transfer ratio, and the execution torque of the front axle and the execution torque of the rear axle are determined respectively.

[0065] Since the rear axle is the main axle in this embodiment, the rear axle torque has a fixed basic distribution ratio p base =100%. In other embodiments, if the front axle is the main axle, the basic distribution ratio of the front axle can still be defined as 100%, and the power can be transferred to another axle according to a certain transfer ratio, thereby realizing the switch from single-axle drive to four-wheel drive.

[0066] Specifically, such as Figure 2 In the second mapping relationship shown, the transfer ratio p offset As the correction parameter increases, it increases in steps. When the correction parameter is greater than or equal to the first threshold, the first transfer ratio p is used. offset_1 Transfer; when the correction parameter continues to increase and is greater than or equal to the second threshold, according to the second transfer ratio p offset_2 Transfer; when the correction parameter is greater than or equal to the third threshold, according to the third transfer ratio p offset_3 Make the transfer.

[0067] Based on the distribution ratio after the transfer, calculate the torque value T after the rear axle motor is distributed Rear,Right now:

[0068] T Rear =T raw ·(p base -p offset )

[0069] Calculate the torque value T after the front axle motor is distributed Rear ,Right now:

[0070] T Front =T raw ·[1-( pbase -p offset )]

[0071] In the above torque calculation method, T raw is the required torque.

[0072] It is understood that in actual implementation, the transfer ratio may have more or fewer levels.

[0073] In the above embodiment, when the vehicle is stable, the lateral stability of the vehicle during driving is taken into consideration, and the vehicle torque is distributed based on the correction parameters, so that the vehicle adopts the corresponding driving mode under different working conditions and fully exerts the vehicle's driving performance.

[0074] In one embodiment, when the adhesion state of the front axle wheels or the rear axle wheels is a stable state and the adhesion state of the other axle is a slipping state, the axle with the stable adhesion state is determined to be the driving axle, and the required torque is determined to be the execution torque of the driving axle.

[0075] For example, in the case of single-axle slip, the torque is transferred to the non-slipping axle, that is, if any wheel on the front axle is unstable, the torque is transferred to the rear axle; if any wheel on the rear axle is unstable and slips, the torque is transferred to the front axle.

[0076] In actual implementation, if the number of slipping wheels on the vehicle exceeds one, the vehicle is determined to be in an unstable state, and the axle that is slipping is further determined based on the wheel speed change rate and wheel speed difference.

[0077] For example, when the wheel speed change rate of any wheel on the front axle is greater than or equal to the change rate threshold, it can be considered that the front axle is slipping.

[0078] Alternatively, if the speed of any wheel on the front axle is too high, far exceeding that of the other rear axle wheels, it can also be considered that the front axle is slipping.

[0079] Similar to the front axle wheels, when the wheel speed change rate of any wheel on the rear axle is greater than or equal to the change rate threshold, the rear axle can be considered to be slipping; or, if the wheel speed of any wheel on the rear axle is too high, far exceeding that of the front axle wheels, the rear axle can also be considered to be slipping.

[0080] In summary, the transfer ratio when the wheel is in a single-axis slip state is determined according to the following mathematical expression:

[0081]

[0082] If both axles have wheels slipping, the execution torque of the front and rear axles is determined according to the preset transfer ratio, for example, the front and rear axles are evenly distributed, that is, p s =50%.

[0083] Using the above method, torque transfer and distribution are carried out based on the state of the slipping wheel in the case of wheel slip, so as to give full play to the adhesion of the front and rear axle wheels, maximize the driving performance of the four-wheel drive vehicle, and improve the vehicle's ability to escape from difficulties.

[0084] In one embodiment, when the vehicle is driving, the wheel end torque is not the greater the better, but there is a limit on the adhesion of the wheel. The adhesion F μi It represents the limit of the tangential reaction force of the ground on each tire. When the vehicle is driving normally on the road, the adhesion of each wheel is proportional to the normal reaction force of the corresponding wheel, that is:

[0085] F μi =μ·F zi

[0086] Where μ is the road adhesion coefficient, which is determined by both the tire and the road surface. The tire characteristics are usually fixed and unchanged. For normal driving roads, the road adhesion coefficient usually does not change suddenly. F zi is the normal reaction force corresponding to each wheel, which is related to the vehicle weight.

[0087] Correspondingly, the ground tangential reaction force caused by the torque acting on each drive wheel cannot be greater than the adhesion, otherwise the wheel will slip. Based on this, the torque extremes of the front and rear axles are calculated separately:

[0088] T imax =μ·F zi ·r wheel

[0089] Among them, r wheel is the tire radius.

[0090] According to Figure 3 The vehicle dynamics model shown in Figure 1 yields:

[0091]

[0092]

[0093] Among them, F zF 、F zRare the normal reaction forces corresponding to the front and rear axles respectively, L is the vehicle wheelbase, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, h g is the height of the center of mass, G is the gravity of the vehicle, m is the mass of the vehicle, α is the slope, and u is the speed in the direction of travel.

[0094] The front axle torque limit T is calculated from this Fmax And the torque limit T of the rear axle Rmax :

[0095]

[0096]

[0097] When the execution torque of the drive shaft is greater than or equal to the torque limit, the execution torque is limited according to the torque limit, so as to perform rear-wheel drive control or four-wheel drive control according to the limited execution torque, that is, the drive control is performed according to the following mathematical expression:

[0098]

[0099]

[0100] By limiting the execution torque of the wheels, slipping caused by excessive torque can be avoided.

[0101] In the above, the slope of the vehicle is based on the longitudinal acceleration signal a collected by the vehicle inertial navigation system. g and longitudinal speed v long Estimate, that is:

[0102]

[0103] Where g is the acceleration due to gravity.

[0104] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0105] In one embodiment, Figure 4As shown, an electric vehicle driving control device is provided, comprising: a monitoring module 201, a calculation module 202 and an execution module 203, wherein:

[0106] The monitoring module 201 is used to determine the adhesion state of the front axle wheels and the rear axle wheels according to the wheel state parameters, wherein the wheel state parameters include the wheel speed change rate and wheel speed difference of each wheel, and the adhesion state includes a stable state and a slip state.

[0107] a calculation module 202 configured to determine, when the adhesion states of the front axle wheels and the rear axle wheels are both in a stable state, a correction parameter from a preset first mapping relationship based on the vehicle speed, the steering wheel angle, and the vehicle body yaw rate, wherein the correction parameter is positively correlated with the vehicle speed, the steering wheel angle, and the vehicle body yaw rate in the mapping relationship;

[0108] The execution module 203 is used to determine the drive shaft and the execution torque, including when the correction parameter is less than a first threshold value, determining that the rear axle of the vehicle is the drive shaft, and determining the required torque of the vehicle as the execution torque of the drive shaft to perform rear-wheel drive control; or when the correction parameter is greater than or equal to the first threshold value, determining that the front axle and the rear axle of the vehicle are both drive shafts, and according to the correction parameter, determining a first transfer ratio of the front axle from a preset second mapping relationship, transferring the required torque to the front axle according to the first transfer ratio, and respectively determining the execution torque of the front axle and the execution torque of the rear axle to switch from rear-wheel drive control to four-wheel drive control.

[0109] The above-mentioned electric vehicle drive control device determines the adhesion status of the front axle wheels and the rear axle wheels through the wheel state parameters, and thereby determines whether the vehicle is in a stable state. When the vehicle is in a stable state, correction parameters reflecting the vehicle's lateral stability and the intensity of the vehicle body deflection are determined based on the vehicle's speed, steering wheel angle and body yaw angular velocity. When the correction parameter is less than a first threshold, it is considered that the vehicle is in a straight line driving at a lower speed. At this time, the rear-wheel drive mode is adopted, which is conducive to the rear wheel adhesion; when the correction parameter reaches or even exceeds the first threshold, it switches to four-wheel drive control to effectively improve driving stability. The above-mentioned method adopts different torque distribution methods under different driving conditions to maximize the driving performance of the four-wheel drive vehicle.

[0110] In one embodiment, the transfer ratio also includes a second transfer ratio. When the correction parameter is greater than a second threshold, the execution module 203 increases the first transfer ratio to obtain the second transfer ratio, so as to determine the execution torque of the front axle and the execution torque of the rear axle respectively according to the second transfer ratio.

[0111] In one embodiment, if the monitoring module 201 detects that a single axis is stable, the execution module 203 determines the stable and non-slip axis as the drive axis, and determines the required torque as the execution torque of the drive axis. If both axes slip, the required torque is distributed to the front axis according to a preset transfer ratio.

[0112] In one embodiment, the execution module 203 determines the torque extremes of the front axle and the rear axle respectively according to the wheel adhesion of the front axle and the rear axle, and limits the execution torque according to the torque extremes to avoid slipping caused by excessive execution torque.

[0113] During the monitoring process of the monitoring module 201 , when the wheel speed change rate is less than the change rate threshold and the maximum wheel speed difference is less than the wheel speed difference threshold, it is determined that both the front axle and the rear axle are in a stable state; otherwise, it is considered that slippage occurs.

[0114] In the presence of slip, if the wheel speed change rate of the front axle wheels is greater than or equal to the change rate threshold, the front axle is considered to be in a slipping state, or if the second wheel speed difference is greater than or equal to the wheel speed difference threshold, then it is determined that the front axle is in a slipping state, and the second wheel speed difference is the difference between the maximum wheel speed among the front axle wheels and the minimum wheel speed among the rear axle wheels.

[0115] On the other hand, when the wheel speed change rate of the rear axle wheels is greater than or equal to the change rate threshold, or the third wheel speed difference is greater than or equal to the wheel speed difference threshold, it is determined that the rear axle is in a slip state.

[0116] The specific definition of the electric vehicle drive control device can be found in the definition of the electric vehicle drive control method above and will not be repeated here. The various modules in the above-mentioned electric vehicle drive control device can be implemented in whole or in part through software, hardware, or a combination thereof. The above-mentioned modules can be embedded in or independent of the processor of the computer device in hardware form, or can be stored in the memory of the computer device in software form, so that the processor can call and execute the corresponding operations of each of the above modules.

[0117] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 5As shown. The computer device includes a processor, a memory, a network interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a method for driving and controlling an electric vehicle is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad provided on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0118] Those skilled in the art will understand that Figure 5 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0119] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the following steps are performed:

[0120] determining the adhesion states of the front and rear axle wheels according to wheel state parameters, wherein the wheel state parameters include the wheel speed change rate and wheel speed difference of each wheel, and the adhesion states include a stable state and a slipping state;

[0121] When the adhesion states of the front axle wheels and the rear axle wheels are both in stable states, determining a correction parameter from a preset first mapping relationship according to the vehicle speed, the steering wheel angle, and the vehicle body yaw rate, wherein the correction parameter is positively correlated with the vehicle speed, the steering wheel angle, and the vehicle body yaw rate in the mapping relationship;

[0122] Determine drive shaft and actuation torque, including:

[0123] When the correction parameter is less than a first threshold, the rear axle of the vehicle is determined to be the drive axle, and the required torque of the vehicle is determined to be the execution torque of the drive axle to perform rear-wheel drive control; or

[0124] When the correction parameter is greater than or equal to the first threshold value, it is determined that the front axle and the rear axle of the vehicle are both drive axles, and based on the correction parameter, the first transfer ratio of the front axle is determined from a preset second mapping relationship, the required torque is transferred to the front axle according to the first transfer ratio, and the execution torque of the front axle and the execution torque of the rear axle are determined respectively to switch from rear-wheel drive control to four-wheel drive control.

[0125] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0126] When the adhesion state of the front axle wheels or the rear axle wheels is a stable state and the adhesion state of the other axle is a slipping state, the axle with the stable adhesion state is determined to be the driving axle, and the required torque is determined to be the execution torque of the driving axle.

[0127] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0128] When the adhesion states of the front axle wheels and the rear axle wheels are both in a slip state, it is determined that the front axle and the rear axle of the vehicle are both drive axles, and the execution torque of the front axle and the rear axle is determined according to a preset transfer ratio to perform four-wheel drive control.

[0129] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0130] Get the wheel adhesion of the front and rear axles;

[0131] determining the torque extremes of the front axle and the rear axle respectively according to the wheel adhesion of the front axle and the rear axle;

[0132] When the execution torque of the drive shaft is greater than or equal to the torque limit, the execution torque is limited according to the torque limit, so as to perform rear-wheel drive control or four-wheel drive control according to the limited execution torque.

[0133] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0134] determining the adhesion state based on a comparison result of the wheel speed change rate and the change rate threshold, and a comparison result of a first wheel speed difference and the wheel speed difference threshold, wherein the first wheel speed difference is a maximum value among the wheel speed differences;

[0135] When the wheel speed change rate is less than a change rate threshold, and the first wheel speed difference is less than a wheel speed difference threshold, it is determined that both the front axle and the rear axle are in a stable state.

[0136] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0137] determining the adhesion states of the front and rear axle wheels according to wheel state parameters, wherein the wheel state parameters include the wheel speed change rate and wheel speed difference of each wheel, and the adhesion states include a stable state and a slipping state;

[0138] When the adhesion states of the front axle wheels and the rear axle wheels are both in stable states, determining a correction parameter from a preset first mapping relationship according to the vehicle speed, the steering wheel angle, and the vehicle body yaw rate, wherein the correction parameter is positively correlated with the vehicle speed, the steering wheel angle, and the vehicle body yaw rate in the mapping relationship;

[0139] Determine drive shaft and actuation torque, including:

[0140] When the correction parameter is less than a first threshold, the rear axle of the vehicle is determined to be the drive axle, and the required torque of the vehicle is determined to be the execution torque of the drive axle to perform rear-wheel drive control; or

[0141] When the correction parameter is greater than or equal to the first threshold value, it is determined that the front axle and the rear axle of the vehicle are both drive axles, and based on the correction parameter, the first transfer ratio of the front axle is determined from a preset second mapping relationship, the required torque is transferred to the front axle according to the first transfer ratio, and the execution torque of the front axle and the execution torque of the rear axle are determined respectively to switch from rear-wheel drive control to four-wheel drive control.

[0142] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0143] When the adhesion state of the front axle wheels or the rear axle wheels is a stable state and the adhesion state of the other axle is a slipping state, the axle with the stable adhesion state is determined to be the driving axle, and the required torque is determined to be the execution torque of the driving axle.

[0144] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0145] When the correction parameter is greater than a second threshold, the first transfer ratio is increased to obtain a second transfer ratio, so as to determine the execution torque of the front axle and the execution torque of the rear axle respectively according to the second transfer ratio, wherein the second threshold is greater than the first threshold.

[0146] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0147] determining the adhesion state of the front axle based on a comparison result of the wheel speed change rate of the front axle wheels with a change rate threshold, or a comparison result of a second wheel speed difference with the wheel speed difference threshold, wherein the second wheel speed difference is obtained by a difference between a maximum wheel speed of the front axle wheels and a minimum wheel speed of the rear axle wheels;

[0148] If the wheel speed change rate of the front axle wheel is greater than or equal to the change rate threshold, or the second wheel speed difference is greater than or equal to the wheel speed difference threshold, it is determined that the front axle is in a slip state;

[0149] determining the adhesion state of the rear axle based on a comparison result of the wheel speed change rate of the rear axle wheels with a change rate threshold, or a comparison result of a third wheel speed difference with the wheel speed difference threshold, wherein the third wheel speed difference is obtained based on a difference between a maximum wheel speed of the rear axle wheels and a minimum wheel speed of the front axle wheels;

[0150] When the wheel speed change rate of the rear axle wheels is greater than or equal to the change rate threshold, or the third wheel speed difference is greater than or equal to the wheel speed difference threshold, it is determined that the rear axle is in a slip state.

[0151] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0152] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0153] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A driving control method for an electric vehicle, characterized in that: include: determining the adhesion states of the front and rear axle wheels according to wheel state parameters, wherein the wheel state parameters include the wheel speed change rate and wheel speed difference of each wheel, and the adhesion states include a stable state and a slipping state; When the adhesion states of the front axle wheels and the rear axle wheels are both in stable states, determining a correction parameter from a preset first mapping relationship according to the vehicle speed, the steering wheel angle, and the vehicle body yaw rate, wherein the correction parameter is positively correlated with the vehicle speed, the steering wheel angle, and the vehicle body yaw rate in the mapping relationship; Determine drive shaft and actuation torque, including: When the correction parameter is less than a first threshold, determining the rear axle of the vehicle as the drive axle, and determining the required torque of the vehicle as the execution torque of the drive axle to perform rear-wheel drive control; When the correction parameter is greater than or equal to the first threshold and less than a second threshold, determining that both the front axle and the rear axle of the vehicle are drive axles, determining a first transfer ratio of the front axle from a preset second mapping relationship based on the correction parameter, transferring the required torque to the front axle according to the first transfer ratio, and determining an execution torque of the front axle and an execution torque of the rear axle, respectively, to switch from rear-wheel drive control to four-wheel drive control; The determining of the torque transfer ratio of the front axle from the preset second mapping relationship further includes: When the correction parameter is greater than or equal to a second threshold and less than a third threshold, the first transfer ratio is increased to obtain a second transfer ratio, so as to determine the execution torque of the front axle and the execution torque of the rear axle respectively according to the second transfer ratio, wherein the second threshold is greater than the first threshold.

2. The electric vehicle driving control method according to claim 1, characterized in that: After determining the adhesion states of the front axle wheels and the rear axle wheels according to the wheel state parameters, the method further includes: When the adhesion state of the front axle wheels or the rear axle wheels is a stable state and the adhesion state of the other axle is a slipping state, the axle with the stable adhesion state is determined to be the driving axle, and the required torque is determined to be the execution torque of the driving axle.

3. The electric vehicle driving control method according to claim 1, characterized in that: After determining the adhesion states of the front axle wheels and the rear axle wheels according to the wheel state parameters, the method further includes: When the adhesion states of the front axle wheels and the rear axle wheels are both in a slip state, it is determined that the front axle and the rear axle of the vehicle are both drive axles, and the execution torque of the front axle and the rear axle is determined according to a preset transfer ratio to perform four-wheel drive control.

4. The electric vehicle driving control method according to claim 1, characterized in that: After determining the drive shaft and executing the torque, the method further includes: Get the wheel adhesion of the front and rear axles; determining the torque extremes of the front axle and the rear axle respectively according to the wheel adhesion of the front axle and the rear axle; When the execution torque of the drive shaft is greater than or equal to the torque limit, the execution torque is limited according to the torque limit, so as to perform rear-wheel drive control or four-wheel drive control according to the limited execution torque.

5. The electric vehicle driving control method according to claim 1, characterized in that: The step of determining the adhesion states of the front and rear axles of the wheels according to the wheel state parameters includes: determining the adhesion state based on a comparison result of the wheel speed change rate and the change rate threshold, and a comparison result of a first wheel speed difference and the wheel speed difference threshold, wherein the first wheel speed difference is a maximum value among the wheel speed differences; When the wheel speed change rate is less than a change rate threshold, and the first wheel speed difference is less than a wheel speed difference threshold, it is determined that both the front axle and the rear axle are in a stable state.

6. The electric vehicle driving control method according to claim 1, characterized in that: The method of determining the adhesion states of the front and rear axles of the wheels according to the wheel state parameters further includes: determining the adhesion state of the front axle based on a comparison result of the wheel speed change rate of the front axle wheels with a change rate threshold, or a comparison result of a second wheel speed difference with the wheel speed difference threshold, wherein the second wheel speed difference is obtained by a difference between a maximum wheel speed of the front axle wheels and a minimum wheel speed of the rear axle wheels; If the wheel speed change rate of the front axle wheel is greater than or equal to the change rate threshold, or the second wheel speed difference is greater than or equal to the wheel speed difference threshold, it is determined that the front axle is in a slip state; determining the adhesion state of the rear axle based on a comparison result of the wheel speed change rate of the rear axle wheels with a change rate threshold, or a comparison result of a third wheel speed difference with the wheel speed difference threshold, wherein the third wheel speed difference is obtained based on a difference between a maximum wheel speed of the rear axle wheels and a minimum wheel speed of the front axle wheels; When the wheel speed change rate of the rear axle wheels is greater than or equal to the change rate threshold, or the third wheel speed difference is greater than or equal to the wheel speed difference threshold, it is determined that the rear axle is in a slip state.

7. An electric vehicle drive control device, characterized in that: The device comprises: a monitoring module, configured to determine the adhesion states of the front and rear axle wheels based on wheel state parameters, wherein the wheel state parameters include a wheel speed change rate and a wheel speed difference of each wheel, and the adhesion states include a stable state and a slipping state; a calculation module, configured to determine, when the adhesion states of the front axle wheels and the rear axle wheels are both in a stable state, a correction parameter from a preset first mapping relationship based on the vehicle speed, the steering wheel angle, and the vehicle body yaw rate, wherein in the mapping relationship, the correction parameter is positively correlated with the vehicle speed, the steering wheel angle, and the vehicle body yaw rate; an execution module, configured to determine a drive shaft and an execution torque, including determining, when the correction parameter is less than a first threshold, that the rear axle of the vehicle is the drive shaft, and determining the required torque of the vehicle as the execution torque of the drive shaft, so as to perform rear-wheel drive control; and when the correction parameter is greater than or equal to the first threshold and less than a second threshold, determining that both the front axle and the rear axle of the vehicle are drive shafts, and determining, based on the correction parameter, a first transfer ratio of the front axle from a preset second mapping relationship, transferring the required torque to the front axle according to the first transfer ratio, and determining the execution torque of the front axle and the execution torque of the rear axle, respectively, so as to switch from rear-wheel drive control to four-wheel drive control; When the correction parameter is greater than or equal to a second threshold and less than a third threshold, the execution module is further used to increase the first transfer ratio to obtain a second transfer ratio, so as to determine the execution torque of the front axle and the execution torque of the rear axle respectively according to the second transfer ratio, wherein the second threshold is greater than the first threshold.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A 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 according to any one of claims 1 to 6 are implemented.

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