Attachment coefficient determination method and device and electronic equipment

Abstract

The invention relates to the technical field of vehicle dynamics, and discloses an adhesion coefficient determination method and device and electronic equipment. The method comprises the steps that the wheel end torque, the wheel angular acceleration, the wheel slip rate and the wheel vertical load of the vehicle are obtained; determining a first longitudinal force of each wheel based on the wheel end torque and the wheel angular acceleration; determining a basic adhesion coefficient of each wheel based on the first longitudinal force and the wheel vertical load; determining a second longitudinal force of each wheel based on the wheel slip rate and a tire model corresponding to the wheel; if the basic adhesion coefficient is smaller than a preset adhesion coefficient threshold value, the second longitudinal force is adopted to correct the basic adhesion coefficient, and the target adhesion coefficient of each wheel is obtained. According to the method, the attachment state of each wheel can be known in time, potential safety hazards caused by inaccurate calculation of the attachment coefficient are reduced, and the driving safety of the vehicle is improved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle dynamics, and particularly to a method, device and electronic device for determining adhesion coefficient. Background Art

[0002] In the power system of a vehicle, due to the advantage that the four-wheel motors of distributed drive can be individually controlled, independent control of the four wheels can be achieved for different working conditions and different control objectives by combining control algorithms. In the anti-skid control function, it is necessary to estimate the adhesion coefficient of the four wheels to determine the maximum available driving force of the four wheels under the current working condition, and limit the maximum output torque value of the anti-skid torque, so that the vehicle can maintain the maximum power while not slipping. Therefore, the accurate determination of the wheel adhesion coefficient can improve the dynamic performance and stability of vehicle anti-skid prohibition.

[0003] In the related art, the adhesion coefficient of the wheel is estimated by the vehicle traction method. However, when the driving torque suddenly increases or decreases, or the wheel acceleration suddenly changes, there will be large deviations and fluctuations in the estimation of the adhesion coefficient, which cannot effectively utilize the dynamic performance of the power system or increase the wheel slip amount, resulting in a large estimation error of the wheel adhesion coefficient, thus affecting the anti-skid performance and stability of the vehicle. Summary of the Invention

[0004] To solve the above technical problems, embodiments of the present application provide a method, device and electronic device for determining adhesion coefficient.

[0005] According to one aspect of the embodiments of the present application, a method for determining adhesion coefficient is provided. The determination method includes: obtaining the wheel-end torque, wheel angular acceleration, wheel slip ratio and wheel vertical load of the vehicle; determining the first longitudinal force of each wheel based on the wheel-end torque and the wheel angular acceleration; determining the basic adhesion coefficient of each wheel based on the first longitudinal force and the wheel vertical load; determining the second longitudinal force of each wheel based on the wheel slip ratio and the tire model corresponding to the wheel; if the basic adhesion coefficient is less than a preset adhesion coefficient threshold, then using the second longitudinal force to correct the basic adhesion coefficient to obtain the target adhesion coefficient of each wheel.

[0006] According to one aspect of the embodiments of the present application, the step of using the second longitudinal force to correct the basic adhesion coefficient to obtain the target adhesion coefficient of each wheel includes: obtaining the road surface type where the vehicle is located; if the road surface type is characterized as a uniform road surface, then obtaining the real-time working condition data of the vehicle; determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data, so as to correct the basic adhesion coefficient based on the correction parameter and the second longitudinal force to obtain the target adhesion coefficient of each wheel.

[0007] According to one aspect of the embodiments of the present application, determining a correction parameter corresponding to the second longitudinal force based on the real-time operating conditions data, and correcting the base adhesion coefficient based on the correction parameter and the second longitudinal force to obtain the target adhesion coefficient of each wheel, includes: determining a weighting parameter corresponding to the first longitudinal force according to the correction parameter, the sum of the weighting parameter and the correction parameter being 1; correcting the second longitudinal force according to the correction parameter to obtain a corrected second longitudinal force; and obtaining the target adhesion coefficient of each wheel according to the weighting parameter, the corrected second longitudinal force, and the base adhesion coefficient.

[0008] According to one aspect of the embodiments of the present application, determining a correction parameter corresponding to the second longitudinal force based on the real-time operating conditions data includes: determining the throttle opening value of the vehicle based on the real-time operating conditions data; if the throttle pedal opening value is greater than a preset throttle pedal opening value, determining a correction parameter corresponding to the second longitudinal force based on the throttle opening value, where the correction parameter has a positive correlation with the throttle opening value.

[0009] According to one aspect of the embodiments of the present application, determining a correction parameter corresponding to the second longitudinal force based on the real-time operating conditions data includes: determining the single-wheel torque change rate of the vehicle based on the real-time operating conditions data; if the single-wheel torque change rate is greater than a preset torque change rate threshold, determining a correction parameter corresponding to the second longitudinal force based on the single-wheel torque change rate, and the positive correlation between the correction parameter and the single-wheel torque change rate is greater than the positive correlation between the correction parameter and the throttle opening value.

[0010] According to one aspect of the embodiments of the present application, determining a correction parameter corresponding to the second longitudinal force based on the real-time operating conditions data includes: determining the difference in base adhesion coefficients between each wheel based on the real-time operating conditions data, where the difference in base adhesion coefficients includes the maximum difference in base adhesion coefficients between the maximum base adhesion coefficient and the minimum base adhesion coefficient among each wheel; determining a correction parameter corresponding to the second longitudinal force based on the maximum difference in base adhesion coefficients, and the correction parameter has a positive correlation with the maximum difference in base adhesion coefficients.

[0011] According to one aspect of the embodiments of the present application, the determination method further includes: obtaining a target adhesion coefficient difference between each wheel, where the target adhesion coefficient difference includes a maximum target adhesion coefficient difference between the maximum target adhesion coefficient and the minimum target adhesion coefficient among each wheel; if the maximum target adhesion coefficient difference is greater than a preset difference threshold and the remaining target adhesion coefficient differences are all less than the preset difference threshold, determining a wheel to be corrected based on the maximum target adhesion coefficient difference; determining an average target adhesion coefficient corresponding to the target wheels of the vehicle, where the target wheels are the other wheels of the vehicle except the wheel to be corrected, and correcting the target adhesion coefficient of the wheel to be corrected based on the average target adhesion coefficient.

[0012] According to one aspect of the embodiments of the present application, the determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data includes: determining a wheel instability state parameter based on the real-time working condition data, where the wheel instability parameter includes the number of wheel slips, the wheel speed overshoot, and the wheel slip duration; determining the correction parameter corresponding to the second longitudinal force based on any one or more of the number of wheel slips, the wheel speed overshoot, and the wheel slip duration; where the correction parameter is positively correlated with the number of wheel slips, the wheel speed overshoot, and the wheel slip duration.

[0013] According to one aspect of the embodiments of the present application, the determination method further includes: if the wheel slip ratio is greater than a preset slip ratio threshold, re-determining the basic adhesion coefficient of the wheel; obtaining the number of wheel slips of the vehicle within a preset duration; if the number of wheel slips is greater than a preset number of slips threshold and the wheel slip ratio is greater than the preset slip ratio threshold, updating the basic adhesion coefficient of each wheel.

[0014] According to one aspect of the embodiments of the present application, there is provided an adhesion coefficient determination device, where the determination device includes: an acquisition module for acquiring the wheel end torque, wheel angular acceleration, wheel slip ratio, and wheel vertical load of the vehicle; a first determination module for determining a first longitudinal force of each wheel based on the wheel end torque and the wheel angular acceleration; a second determination module for determining the basic adhesion coefficient of each wheel based on the first longitudinal force and the wheel vertical load; a third determination module for determining a second longitudinal force of each wheel based on the wheel slip ratio and the tire model corresponding to the wheel; a correction module for, if the basic adhesion coefficient is less than a preset adhesion coefficient threshold, correcting the basic adhesion coefficient with the second longitudinal force to obtain the target adhesion coefficient of each wheel.

[0015] According to one aspect of the embodiments of the present application, an electronic device is provided, including: one or more processors; a storage device for storing one or more programs, which, when executed by the one or more processors, cause the electronic device to implement the determination method as described above.

[0016] According to one aspect of the embodiments of the present application, a computer-readable storage medium is provided, on which computer-readable instructions are stored, which, when executed by a processor of a computer, cause the computer to execute the determination method as described above.

[0017] According to one aspect of the embodiments of the present application, a computer program product is further provided, including a computer program, which, when executed by a processor, implements the steps in the determination method as described above.

[0018] In the technical solution provided by the embodiments of the present application, by comprehensively considering the wheel-end data of the vehicle and the tire model to obtain the first longitudinal force and the second longitudinal force of the wheel, the force state of the wheel during driving can be more comprehensively reflected. The combined use of these two longitudinal forces can further improve the accuracy of the adhesion coefficient calculation. By directly calculating the basic adhesion coefficient through the ratio of the first longitudinal force to the vertical load, sudden changes in road surface adhesion can be captured within milliseconds. When the basic coefficient is lower than the threshold, the second longitudinal force calculated by the tire model is introduced for correction to avoid underestimating the wheel adhesion coefficient due to the non-linear characteristics of road surface friction, significantly improving the real-time performance, accuracy, and adaptability of the adhesion coefficient estimation, providing more reliable basic data support for vehicle dynamics control, helping to timely understand the adhesion state of the wheel, reducing potential safety hazards caused by inaccurate calculation of the adhesion coefficient, and improving the driving safety of the vehicle.

[0019] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0021] Figure 1 It is a schematic diagram of an implementation environment for determining the adhesion coefficient during driving shown in an exemplary embodiment of the present application.

[0022] Figure 2 It is a flowchart of a method for determining the adhesion coefficient shown in an exemplary embodiment of the present application.

[0023] Figure 3 It is the specific flowchart of step S250 shown in an exemplary embodiment of the present application. Figure 2 in

[0024] Figure 4 It is the specific flowchart of step S330 shown in an exemplary embodiment of the present application. Figure 3 in

[0025] Figure 5 It is the specific flowchart of step S330 in another embodiment shown in the embodiment of the present application. Figure 3 in

[0026] Figure 6 It is the specific flowchart of step S330 in another embodiment shown in the embodiment of the present application. Figure 3 in

[0027] Figure 7 It is the specific flowchart of step S330 in another embodiment shown in the embodiment of the present application. Figure 3 in

[0028] Figure 8 It is the flowchart of a method for determining adhesion coefficient shown in another exemplary embodiment of the present application.

[0029] Figure 9 It is the specific flowchart of step S330 in another embodiment shown in the embodiment of the present application. Figure 3 in

[0030] Figure 10 It is the flowchart of a method for determining adhesion coefficient shown in another exemplary embodiment of the present application.

[0031] Figure 11 It is the block diagram of an adhesion coefficient determination device shown in an exemplary embodiment of the present application.

[0032] Figure 12 It shows the schematic structural diagram of a computer system of an electronic device suitable for implementing the embodiment of the present application.

[0033] Explanation of reference numerals: intelligent terminal 110, adhesion coefficient determination device 1100, acquisition module 1110, first determination module 1120, second determination module 1130, third determination module 1140, correction module 1150, computer system 1200, CPU 1201, ROM 1202, RAM 1203, bus 1204, I / O interface 1205, input part 1206, output part 1207, storage part 1208, communication part 1209, driver 1210, removable medium 1211. Detailed Implementation Modes

[0034] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation modes described in the following exemplary embodiments do not represent all implementation modes consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0035] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0036] The flowcharts shown in the drawings are only exemplary illustrations and do not necessarily include all contents and operations / steps, nor do they necessarily need to be executed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0037] In the present application, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0038] The wheel adhesion coefficient refers to the static friction coefficient between the tire and the road surface, which reflects the adhesion ability of the tire under different road surface conditions. In essence, it is the combined result of the mechanical engagement, molecular adhesion, and hysteresis loss of the microstructures of the tire and the road surface. It determines the maximum longitudinal / lateral force that the vehicle can transmit under specific conditions and directly affects the acceleration limit, braking performance, and steering response of the vehicle. There are many influencing factors for the adhesion coefficient, mainly including tire characteristics (material, tread pattern, wear degree, tire pressure), road surface conditions (dry, wet, snow-covered, gravel), temperature (tire and road surface temperature), vehicle speed (affecting the contact area and deformation of the tire), and vehicle load (affecting the ground pressure distribution of the tire). In terms of the calculation method, it can be measured through experiments, usually through braking tests or traction tests. Under a known vertical load, the maximum braking force or driving force is measured, and then the adhesion coefficient (μ) is calculated.

[0039] Figure 1 is a schematic diagram of the implementation environment for determining the adhesion coefficient during vehicle driving shown in an exemplary embodiment of the present application. As Figure 1As shown, during vehicle driving, the intelligent terminal 110 can obtain the wheel-end torque, wheel angular acceleration, wheel slip ratio, and wheel vertical load of the vehicle. Then, the first longitudinal force of the vehicle's wheel can be calculated based on the wheel-end torque and wheel angular acceleration, and the basic adhesion coefficient of the wheel can be determined based on the first longitudinal force and the wheel vertical load. Then, the intelligent terminal 110 can determine the second longitudinal force of the wheel based on the wheel slip ratio and the corresponding tire model of the wheel. Then, if the basic adhesion coefficient is less than the preset adhesion coefficient threshold, the second longitudinal force is used to correct the basic adhesion coefficient to obtain the target adhesion coefficient of the wheel. In this way, the accurate estimation of the adhesion coefficient of the vehicle on the road surface is realized.

[0040] Among them, Figure 1 The intelligent terminal 110 shown can be any terminal device that supports data collection and processing, such as in-vehicle equipment, smartphones, in-vehicle computers, tablets, laptops, or wearable devices, but is not limited thereto.

[0041] In the vehicle's powertrain, due to the advantage that the four-wheel motors of distributed drive can be individually controlled, independent control of the four wheels can be achieved for different working conditions and different control objectives by combining control algorithms. In the anti-skid control function, it is necessary to estimate the adhesion coefficients of the four wheels to determine the maximum available driving force of the four wheels under the current working conditions and limit the maximum output torque value of the anti-skid torque, so that the vehicle can maintain the maximum power while not skidding. Therefore, the accurate determination of the wheel adhesion coefficient can improve the dynamic performance and stability of the vehicle's anti-skid prohibition.

[0042] In the related art, the adhesion coefficient of the wheel is estimated by the vehicle traction method. However, when the driving torque suddenly increases or decreases, or the wheel acceleration suddenly changes, there will be large deviations and fluctuations in the estimation of the adhesion coefficient, which cannot effectively utilize the dynamic performance of the powertrain or increase the wheel slip, resulting in a large estimation error of the wheel adhesion coefficient and thus affecting the anti-skid performance of the vehicle.

[0043] The problems pointed out above are generally applicable in common travel scenarios. It can be seen that the existing calculation methods of the adhesion coefficient are not accurate enough, with large errors, affecting the anti-skid performance of the vehicle. To solve these problems, the embodiments of the present application respectively propose an adhesion coefficient determination method, an adhesion coefficient determination device, an electronic device, a computer-readable storage medium, and a computer program product, which will be described in detail below.

[0044] Please refer to Figure 2 , Figure 2 which is a flowchart of the adhesion coefficient determination method shown in an exemplary embodiment of the present application. This method can be applied to Figure 1The described implementation environment, and is specifically executed by the intelligent terminal 110 in this implementation environment. It should be understood that this method can also be applied to other exemplary implementation environments and be specifically executed by devices in other implementation environments. This embodiment does not limit the implementation environment applicable to this method.

[0045] As Figure 2 shown, in an exemplary embodiment, the adhesion coefficient determination method at least includes steps S210 to S250, which are introduced in detail as follows: Step S210, obtain the wheel-end torque, wheel angular acceleration, wheel slip ratio, and wheel vertical load of the vehicle.

[0046] The wheel-end torque of the vehicle refers to the driving torque actually output by the driving wheel, which is formed by amplifying or attenuating the engine torque through the transmission system. Usually, the wheel-end torque can be obtained by a strain gauge sensor pasted on the surface of the vehicle drive shaft, or the wheel-end torque can be determined by the change in the magnetic permeability of the magnetic material of the magnetic sensor under the action of torque. In some pure electric or hybrid vehicles, the wheel-end torque of the vehicle can also be determined by the phase current and magnetic field parameters of the drive motor. The wheel angular acceleration can also be obtained by differentiating the wheel speed signal of the vehicle. Among them, the wheel angular velocity reflects the transient change rate of the tire rotation; the slip ratio is a parameter describing the degree of slippage between the wheel and the road surface, and it is defined as the ratio of the sliding speed of the wheel to the rolling speed of the wheel. Therefore, the slip ratio can be obtained from the rolling speed of the wheel and the rolling speed of the wheel, or other methods can also be used; the wheel vertical load can be calculated by combining the suspension stroke sensor with the suspension stiffness, or other methods can also be used.

[0047] Step S220, determine the first longitudinal force of each wheel based on the wheel-end torque and the wheel angular acceleration.

[0048] The wheel-end torque refers to the torque acting on the wheel, usually generated by the motor or the engine, and the wheel angular acceleration is the speed of the vehicle. The longitudinal force should refer to the force of the wheel in the driving direction, that is, the traction force or the braking force. The wheel angular acceleration may affect the wheel slip ratio, and thus affect the longitudinal force. If there is a difference between the wheel angular acceleration and the wheel speed, that is, when slippage occurs, the longitudinal force may not only be determined by the torque, but also related to the slip ratio.

[0049] Optionally, first calculate the theoretical longitudinal force based on the wheel-end torque and the wheel radius, and then correct it according to the vehicle speed. For example, when the vehicle speed is very high, the tire may be close to or reach the adhesion limit, and at this time the actual longitudinal force may be less than the theoretically calculated value. Or, if the wheel speed corresponding to the wheel angular acceleration is inconsistent with the wheel speed calculated based on the torque, it may involve the efficiency or loss of the power transmission system. Or, the wheel angular acceleration may be used to calculate the angular velocity of the wheel, and then combined with the torque to calculate the power, and then derive the force. In some feasible embodiments, the first longitudinal force of the vehicle's wheels can also be calculated by the traction method. Among them, the traction method mainly calculates the longitudinal force of the vehicle based on the wheel-end torque and the wheel angular acceleration, and then calculates the first longitudinal force of each wheel of the vehicle.

[0050] Wherein, is the first longitudinal force of the wheel, the wheel-end torque of each wheel, is the wheel-end moment of inertia of each wheel, is the wheel angular acceleration of each wheel, is the wheel radius.

[0051] Step S230, determine the base adhesion coefficient of each wheel based on the first longitudinal force and the wheel vertical load.

[0052] Exemplarily, the base adhesion coefficient of each wheel can be obtained according to the ratio of the first longitudinal force to the wheel vertical load. The base adhesion coefficient is a key parameter in vehicle dynamics control. Its essence is the proportion of the maximum frictional force that can be utilized between the tire and the road surface at the current moment. By combining the first longitudinal force derived from the wheel-end torque and the wheel angular acceleration with the vertical load, the current road surface adhesion ability can be quickly estimated, providing a benchmark for subsequent slip ratio control and traction force distribution. Therefore, the base adhesion coefficient reflects the frictional force utilization potential of the tire under the current working conditions (without considering the non-linear effect of the slip ratio). Among them, the wheel vertical load includes the static load determined by the vehicle mass distribution and the dynamic load affected by the pitching and rolling motions of the vehicle.

[0053] Step S240, determine the second longitudinal force of each wheel based on the wheel slip ratio and the tire model corresponding to the wheel.

[0054] The TireModel is a mathematical model used to describe the mechanical behavior of a tire when it comes into contact with the ground. Its core objective is to quantify the dynamic characteristics such as longitudinal forces (driving / braking forces), lateral forces (cornering forces), aligning moments (self-aligning moments), and vertical load distribution generated by the tire under different operating conditions. It is a core tool for vehicle dynamics analysis, control system design, and simulation. Common types of tire models include, for example, the Magic Formula, the Brush Model, the Linear Model, etc. That is to say, once the road surface condition information is obtained and a suitable tire model is selected, the second longitudinal force of the wheel can be calculated. Specifically, parameters such as the road surface friction coefficient, road surface unevenness, road surface material, road surface temperature, and humidity can be input into the tire model; the current state of the tire, such as air pressure, wear level, temperature, etc., which also affect the mechanical behavior of the tire, is determined, and then kinematic parameters such as the rotational speed of the wheel, slip ratio, and sideslip angle are input. Then, based on the tire model and the input parameters, the longitudinal force of the wheel is calculated. In the case of the Magic Formula, this usually involves a series of complex mathematical operations, including trigonometric functions, exponential functions, and polynomials, and then the second longitudinal force of the wheel is output. This force is the result of the interaction between the tire and the road surface, taking into account the influence of road surface conditions and tire characteristics.

[0055] Exemplarily, the second longitudinal force is the transient longitudinal force of the tire in the non-linear friction region (such as braking skid or driving skid), which directly affects the response accuracy of vehicle stability control. Through the combined calculation of the slip ratio (λ) and the tire model, the ultimate friction capacity of the tire can be dynamically predicted. Among them, the slip ratio characterizes the relative sliding degree between the wheel and the ground, and the slip ratio of the wheel can also be determined by the wheel center speed, the rolling radius of the wheel, and the wheel angular velocity.

[0056] In some realizable embodiments, the Magic Formula can be selected as the tire model, and then the second longitudinal force corresponding to each wheel of the vehicle is calculated according to the Magic Formula as follows: Where, is the second longitudinal force of the wheel, is the wheel slip ratio, , , , are the stiffness factor, shape factor, peak factor, and curvature factor respectively. Regarding the stiffness factor , the shape factor , the peak factor and the curvature factor , can be determined according to the tires of the vehicle and the road surface characteristics where the vehicle is located. Therefore, during the application process, it may be necessary to adjust and verify parameters according to factors such as different tire types, sizes, air pressures, and road conditions. The wheel slip ratio is the proportion of the sliding degree of the wheel relative to the pure rolling state.

[0057] Step S250, if the base adhesion coefficient is less than the preset adhesion coefficient threshold, then use the second longitudinal force to correct the base adhesion coefficient to obtain the target adhesion coefficient of each wheel.

[0058] Exemplarily, if the base adhesion coefficient is less than the preset threshold (for example, the wet and slippery road surface threshold is set to 0.4), it means that the credibility of the adhesion coefficient obtained by using the first longitudinal force is relatively low, and the correction process needs to be started. The actual longitudinal force (the second longitudinal force) between the tire and the ground is calculated in real time through a tire model (such as the Magic Formula). For example, the transient friction characteristics (such as the non-linear change of the friction force caused by the change of the slip ratio) can be captured, and the target adhesion coefficient is gradually increased according to the slip ratio. Among them, the correction amplitude of the second longitudinal force increases as the slip ratio increases, avoiding the influence of the wheel slip ratio on the accuracy of the wheel adhesion coefficient calculation. Furthermore, the target adhesion coefficient corresponding to each wheel of the vehicle can be calculated.

[0059] In some embodiments of the present application, by comprehensively considering the wheel end data of the vehicle and the tire model to obtain the first longitudinal force and the second longitudinal force of the wheel, the force state of the wheel during driving can be more comprehensively reflected. The combined use of these two longitudinal forces can further improve the accuracy of the adhesion coefficient calculation. The base adhesion coefficient is directly calculated by the ratio of the first longitudinal force to the vertical load, and the sudden change of the road surface adhesion can be captured within milliseconds. When the base coefficient is lower than the threshold, the second longitudinal force calculated by the tire model is introduced for correction, avoiding the underestimation of the wheel adhesion coefficient due to the non-linear characteristics of the road surface friction force, significantly improving the real-time performance, accuracy and adaptability of the adhesion coefficient estimation, providing more reliable basic data support for vehicle dynamics control, helping to timely understand the adhesion state of the wheel, reducing potential safety hazards caused by inaccurate adhesion coefficient calculation, and improving the driving safety of the vehicle.

[0060] Based on the above embodiments, please refer to Figure 3 , in one exemplary embodiment provided by the present application, the specific implementation process of using the second longitudinal force to correct the base adhesion coefficient to obtain the target adhesion coefficient of each wheel may further include steps S310 to S330, which are introduced in detail as follows: Step S310, obtain the road surface type where the vehicle is located; Step S320, if the road surface type is characterized as a uniform road surface, obtain the real-time working condition data of the vehicle; Step S330: Determine the correction parameter corresponding to the second longitudinal force based on the real-time working condition data, so as to correct the basic adhesion coefficient based on the correction parameter and the second longitudinal force, and obtain the target adhesion coefficient of each wheel.

[0061] Exemplarily, road surface types can usually be classified according to various factors such as road surface materials, structural characteristics, and usage conditions. For example, during vehicle driving, road surface condition information can be collected through on-vehicle sensors (such as cameras, radars, acceleration sensors, etc.), including road surface flatness, friction coefficient, material type (such as asphalt, concrete, gravel, etc.), humidity, temperature, etc. Then, based on this information, machine learning algorithms or expert systems can be used to identify the road surface type. For example, by comparing the collected information with the feature library of known road surface types, the most matching road surface type can be determined. Common road surface types in applications include: highway road surfaces usually composed of asphalt or concrete, with high flatness and moderate friction coefficient; urban road surfaces that may include asphalt, concrete or masonry road surfaces, with relatively high flatness, but may be affected by factors such as traffic flow and weather; rural road surfaces that may include dirt roads, gravel roads or concrete / asphalt road surfaces, with low flatness and large variations in friction coefficient, and special road surfaces such as ice and snow road surfaces, slippery road surfaces, muddy road surfaces, etc. These road surface types have a significant impact on vehicle driving performance.

[0062] In addition, it is also possible to determine whether the road surface type where the vehicle is located is a uniform road surface according to the error magnitude between the basic adhesion coefficients of each wheel of the vehicle. If the error magnitude is within the allowable error range, it can be determined that the road surface type where the vehicle is located is a uniform road surface. In some embodiments of the present application, real-time operating condition data can be used to determine the vehicle parameters of the vehicle at the current moment (e.g., vehicle speed, acceleration, driving or braking torque, wheel speed, slip ratio, vertical load, throttle opening value, single-wheel torque change rate, wheel instability state parameters, basic adhesion coefficient, etc.). The wheel instability state parameters include, but are not limited to, the number of wheel slips, the overshoot of the wheel speed, and the duration of wheel slip. Then, the correction parameter corresponding to the second longitudinal force can be determined according to the real-time operating condition data of the vehicle. Among them, the logic corrected by the real-time operating condition information of the vehicle includes, but is not limited to, when the vehicle accelerates or brakes violently, the load will transfer between the front and rear wheels, and the correction parameter corresponding to the second longitudinal force is determined according to the acceleration and vehicle parameters (such as the height of the center of mass, the wheelbase), or when the dynamic torque is close to the tire adhesion limit, the correction parameter corresponding to the second longitudinal force is determined according to the ratio of the actual torque to the limit torque, or when driving in a curve, the lateral acceleration will affect the longitudinal grip of the tire, and the correction parameter corresponding to the second longitudinal force is determined by estimating the turning radius through the steering wheel angle or the lateral acceleration sensor, or the correction parameter corresponding to the second longitudinal force is determined by considering the influence of tire temperature or wear on the adhesion performance. Finally, the basic adhesion coefficient of the wheel is corrected by combining the correction parameter corresponding to the second longitudinal force, and then the target adhesion coefficient of the wheel is obtained.

[0063] In some embodiments of the present application, by comprehensively using the basic adhesion coefficient, road surface type judgment, real-time operating condition data, and the second longitudinal force correction parameter, the force condition of the wheel on the actual road surface can be more accurately reflected, thereby improving the accuracy of the adhesion coefficient calculation, and making the calculation of the adhesion coefficient more flexible and accurate, which helps to cope with the complex and changeable road environment and improve the safety and stability of vehicle driving.

[0064] Based on the above embodiments, please refer to Figure 4 , in one exemplary embodiment provided by the present application, the specific implementation process of determining the correction parameter corresponding to the second longitudinal force based on the real-time operating condition data, and correcting the basic adhesion coefficient based on the correction parameter and the second longitudinal force to obtain the target adhesion coefficient of each wheel may further include steps S410 to S430, which are introduced in detail as follows: Step S410, determine the weighting parameter corresponding to the first longitudinal force according to the correction parameter, and the sum of the weighting parameter and the correction parameter is 1; Step S420, correct the second longitudinal force according to the correction parameter to obtain the corrected second longitudinal force; Step S430, obtain the target adhesion coefficient of each wheel according to the weighting parameter, the corrected second longitudinal force, and the basic adhesion coefficient.

[0065] Continuing from the above embodiments, correction parameters are calculated based on real-time operating condition data (such as acceleration, torque, lateral force, etc.), and these parameters reflect the degree of influence of the current operating condition on the adhesion coefficient. The range of the correction parameter is usually between 0 and 1, and the larger the value, the more significant the influence of the operating condition. For example, the weighting coefficient corresponding to the first longitudinal force can be determined according to the correction parameter corresponding to the second longitudinal force, where the sum of the weighting coefficient and the correction parameter is 1, and the weighting parameter and the correction parameter are complementary to ensure that their sum is 1. Then, the weighting parameter is applied to the basic adhesion coefficient, and at the same time, the corrected second longitudinal force is incorporated, and the correction parameter is used to adjust the second longitudinal force. The larger the correction parameter, the greater the adjustment amplitude of the second longitudinal force. Then, through weighted average or proportional mixing, the basic adhesion coefficient and the corrected second longitudinal force are combined to obtain the final target adhesion coefficient of the wheel. In this way, the target adhesion coefficients of each wheel of the vehicle are calculated.

[0066] In some realizable embodiments, the adhesion coefficient corresponding to the wheel can be calculated through the first longitudinal force and the second longitudinal force of the wheel, as follows: Wherein, is the target adhesion coefficient of the wheel, represents the wheel, is the first longitudinal force of the wheel; is the second longitudinal force of the wheel; is the vertical load of each wheel; is the weighting coefficient corresponding to the first longitudinal force, is the correction parameter corresponding to the second longitudinal force. Furthermore, the target adhesion coefficient corresponding to the wheel can be determined according to the first longitudinal force and the second longitudinal force of the wheel. When is 1, is 0, is the basic adhesion coefficient corresponding to each wheel.

[0067] In some embodiments of the present application, by introducing a weighting parameter associated with the correction parameter, comprehensively correcting the second longitudinal force and combining the basic adhesion coefficient to obtain the target adhesion coefficient can more accurately adapt to the vehicle driving state and road surface conditions, and significantly improve the accuracy of wheel adhesion coefficient estimation and vehicle control stability.

[0068] Further, based on the above embodiments, please refer to Figure 5 , in one exemplary embodiment provided by the present application, the specific implementation process of determining the correction parameter corresponding to the second longitudinal force based on real-time operating condition data may further include step S510 and step S520, which are introduced in detail as follows: Step S510, determining the throttle opening value of the vehicle based on real-time operating condition data; Step S520: If the throttle pedal opening value is greater than the preset throttle pedal opening value, determine the correction parameter corresponding to the second longitudinal force based on the throttle opening value, where the correction parameter has a positive correlation with the throttle opening value.

[0069] Exemplarily, the position signal of the vehicle's throttle pedal can be determined through the vehicle's communication bus or sensor system. Among them, the position signal of the throttle pedal can be converted into a throttle opening value. Then, it is judged whether the throttle opening value is greater than the preset throttle opening threshold, which is set according to the vehicle performance and driving requirements. If the throttle opening value of the vehicle is greater than the preset throttle opening threshold, enter the correction parameter determination link. Among them, the correction parameter corresponding to the second longitudinal force can be determined through the pre-established positive correlation between the throttle opening value and the correction parameter value. Then, adjust the second longitudinal force (such as driving torque or tire force) according to the correction parameter to match the power demand at high throttle openings, and ensure that the deeper the throttle is pressed, the more active the correction of the wheel adhesion coefficient is combined with the positive correlation design.

[0070] Optionally, as shown in Table 1 below, taking the preset throttle opening threshold as 80% as an example, the positive correlation between the throttle opening value of the vehicle and the correction parameter can be preset and mapped into the corresponding numerical relationship.

[0071] Table 1 Furthermore, after determining the throttle opening value of the vehicle according to the vehicle's real-time working condition data, the correction parameter corresponding to the second longitudinal force and the weighting coefficient corresponding to the first longitudinal force can be quickly determined according to Table 1.

[0072] In some embodiments of the present application, the throttle opening value is accurately obtained based on the real-time working condition data, and the opening threshold is set to trigger the correction mechanism. When the throttle pedal opening value reaches above the preset value, the correction parameter changes positively with the throttle opening value, which can dynamically adapt to the driver's acceleration intention and the vehicle's power demand, timely and accurately adjust the correction parameter of the second longitudinal force, effectively improve the accuracy of the adhesion coefficient estimation of the vehicle under different acceleration conditions, enhance the power response and driving stability of the vehicle during acceleration, avoid the risk of insufficient power output or wheel skidding out of control caused by the adhesion coefficient estimation deviation, and improve the driving safety and handling experience.

[0073] Based on the above embodiments, please refer to Figure 6 , in one exemplary embodiment provided by the present application, the specific implementation process of determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data may further include Step S610 and Step S620, which are introduced in detail as follows: Step S610: Determine the single-wheel torque change rate of the vehicle based on the real-time working condition data; Step S620: If the single-wheel torque change rate is greater than the preset torque change rate threshold, determine the correction parameter corresponding to the second longitudinal force based on the single-wheel torque change rate. The positive correlation between the correction parameter and the single-wheel torque change rate is greater than the positive correlation between the correction parameter and the throttle opening value.

[0074] Exemplarily, the torque signals corresponding to the respective wheels of the vehicle can be obtained through the communication bus or wheel speed sensors of the vehicle, and then the single-wheel torque change rate of the vehicle can be calculated based on the torque signals. The single-wheel torque change rate is the change rate of the torque of a single wheel of the vehicle per unit time, and the real-time change rate value of the single wheel can be obtained by differentiating or differencing the torque signal of the wheel. Then, the single-wheel torque change rate is compared with the preset torque change rate threshold. The preset torque change rate threshold can be set according to the vehicle power system and control requirements. If the single-wheel torque change rate is greater than the preset torque change rate threshold, enter the process of determining the correction parameter corresponding to the second longitudinal force. For example, a positive correlation relationship can be established between the single-wheel torque change rate and the correction parameter, and the greater the single-wheel torque change rate, the higher the value of the correction parameter, and its growth rate is faster than the correction parameter related to the throttle opening.

[0075] Optionally, as shown in Table 2 below, taking the preset single-wheel torque change rate of 50 as an example (unit: Nm / 100ms), the positive correlation relationship between the single-wheel torque change rate of the vehicle and the correction parameter can be preset and mapped into the corresponding numerical relationship.

[0076] Table 2 Furthermore, after determining the single-wheel torque change rate of the vehicle based on the real-time working condition data of the vehicle, the correction parameter corresponding to the second longitudinal force and the weighting coefficient corresponding to the first longitudinal force can be quickly determined according to Table 2.

[0077] In some embodiments of the present application, the single-wheel torque change rate of the vehicle is determined through real-time working condition data. Taking the preset threshold as the judgment basis, when the single-wheel torque change rate exceeds the threshold, the correction parameter of the second longitudinal force is determined based on it, and a stronger positive correlation is given between the single-wheel torque change rate and the correction parameter, which can more sensitively capture the drastic fluctuation of the single-wheel torque during vehicle driving, quickly and accurately adjust the correction parameter. Compared with only considering the throttle opening value, it can more timely and effectively respond to the change of the adhesion situation caused by torque mutation under complex working conditions, significantly improve the accuracy of the adhesion coefficient estimation of the vehicle under working conditions such as rapid acceleration and sudden lane change, enhance the driving stability and safety of the vehicle, and optimize the handling performance.

[0078] Based on the above embodiments, please refer to Figure 7, in one exemplary embodiment provided by the present application, the specific implementation process of determining the correction parameter corresponding to the second longitudinal force based on real-time operating conditions data may further include step S710 and step S720, which are introduced in detail as follows: Step S710, determining the difference in basic adhesion coefficients between the wheels of the vehicle based on real-time operating conditions data, where the difference in basic adhesion coefficients includes the maximum difference in basic adhesion coefficients between the maximum basic adhesion coefficient and the minimum basic adhesion coefficient among the wheels. Step S720, if the maximum difference in basic adhesion coefficients is greater than the first preset difference threshold, determining the correction parameter corresponding to the second longitudinal force based on the maximum difference in basic adhesion coefficients, and the correction parameter has a positive correlation with the maximum difference in basic adhesion coefficients.

[0079] Continuing from the above embodiment, the basic adhesion coefficients corresponding to the wheels of the vehicle determined through the above embodiment based on the real-time operating conditions data of the vehicle can be used. For example, the left front wheel , the right front wheel , the left rear wheel , the right rear wheel , and then the maximum value and the minimum value are found from the basic adhesion coefficients of all the wheels, and the maximum difference in basic adhesion coefficients between the maximum value and the minimum value is calculated. This difference reflects the degree of difference in the adhesion conditions between the wheels of the vehicle and the road surface (such as split road surfaces, partial skidding, or uneven ice and snow coverage), and the magnitude relationship between the maximum basic coefficient difference and the first preset difference threshold is judged. Among them, the first preset difference threshold is a threshold set according to the vehicle dynamics characteristics and control requirements. If the maximum difference in basic adhesion coefficients is greater than the first preset difference threshold, a positive correlation between the maximum basic adhesion difference and the correction parameter corresponding to the second longitudinal force can be established. Furthermore, the greater the maximum difference in basic adhesion coefficients , the higher the value of the correction parameter, reflecting that the influence of uneven road surface adhesion on control is more significant. The correction parameter is used to adjust the second longitudinal force (such as drive torque distribution or braking pressure) to compensate for the adhesion difference between the wheels. The positive correlation design ensures that the greater the adhesion difference, the more actively the system corrects the adhesion coefficient.

[0080] Optionally, as shown in Table 3 below, taking the first preset difference threshold as 0.05 as an example, the positive correlation between the maximum difference in basic adhesion coefficients of the vehicle and the correction parameter can be preset and mapped into the corresponding numerical relationship.

[0081] Table 3 Furthermore, after determining the maximum difference in basic adhesion coefficients between the wheels of the vehicle based on the real-time operating condition data of the vehicle, the correction parameter corresponding to the second longitudinal force and the weighting coefficient corresponding to the first longitudinal force can be quickly determined according to Table 3.

[0082] In some embodiments of the present application, the difference in basic adhesion coefficients between the wheels of the vehicle (especially the maximum difference in basic adhesion coefficients) is calculated through real-time operating condition information. Taking the first preset difference threshold as the judgment criterion, when the difference exceeds the limit, the correction parameter of the second longitudinal force is determined based on it and the two are positively correlated. It can keenly sense the difference in adhesion conditions between the wheels, and accurately adjust the correction parameter in a timely manner when significant differences occur, effectively coping with the uneven wheel adhesion caused by factors such as road surface unevenness and vehicle tilt, significantly improving the accuracy of adhesion coefficient estimation of the vehicle on complex adhesion road surfaces, enhancing the driving stability and safety of the vehicle, and optimizing the handling performance of the vehicle under different road conditions.

[0083] Based on the above embodiments, please refer to Figure 8 , in one exemplary embodiment provided by the present application, the specific implementation process of the above adhesion coefficient determination method may further include steps S810 to S840, which are introduced in detail as follows: Step S810, obtain the target adhesion coefficient difference between each wheel, and the target adhesion coefficient difference includes the maximum target adhesion coefficient difference between the maximum target adhesion coefficient and the minimum target adhesion coefficient among each wheel; Step S820, if the maximum target adhesion coefficient difference is greater than the preset difference threshold and the remaining target adhesion coefficient differences are all less than the preset difference threshold, determine the wheel to be corrected based on the maximum target adhesion coefficient difference; Step S830, determine the average target adhesion coefficient corresponding to the target wheel of the vehicle, where the target wheel is the other wheels of the vehicle except the wheel to be corrected, and correct the target adhesion coefficient of the wheel to be corrected based on the average target adhesion coefficient.

[0084] In accordance with the above embodiment, after calculating the target adhesion coefficients corresponding to each wheel of the vehicle, the target adhesion coefficient difference between the target adhesion coefficients of each wheel of the vehicle can be calculated, in particular, the maximum target adhesion coefficient and the minimum target adhesion coefficient are determined, and the difference between them, i.e., the maximum target adhesion coefficient difference, is calculated. Then the calculated maximum target adhesion coefficient difference is compared with a preset difference threshold, which is set according to the design, performance requirements and safety considerations of the vehicle. At the same time, it is also necessary to check whether the target adhesion coefficient differences between other wheels are all less than the preset difference threshold, in order to ensure that only the maximum target adhesion coefficient difference is significantly larger, while the other differences are within an acceptable range. If the maximum target adhesion coefficient difference is greater than the preset difference threshold, and the remaining target adhesion coefficient differences are all less than the preset difference threshold, then it can be determined that there is a wheel whose target adhesion coefficient is significantly different from that of the other wheels, and the wheel is the wheel to be corrected, and the target wheel refers to the other wheels in the vehicle except the wheel to be corrected. Then, the average value of the target adhesion coefficients of these target wheels, i.e., the average target adhesion coefficient, can be calculated, and then the target adhesion coefficient of the wheel to be corrected can be corrected based on the calculated average target adhesion coefficient. The purpose of the correction is to make the target adhesion coefficient of the wheel to be corrected closer to the target adhesion coefficients of other wheels, thereby improving the driving stability and safety of the vehicle. After the target adhesion coefficient of the wheel to be corrected is corrected, the target adhesion coefficient differences between the wheels need to be checked again to ensure that the maximum target adhesion coefficient difference has been reduced to an acceptable range and that other differences are also kept at a reasonable level.

[0085] In addition, in some feasible embodiments, after the target adhesion coefficient of the wheel is updated, if the slip rate of the wheel is less than the preset slip rate threshold within the preset time period after the target adhesion coefficient is updated, the target adhesion coefficient of the wheel may no longer be continuously updated; if it continues for the preset time period, the target adhesion coefficient of the wheel currently calculated may be compared with the target adhesion coefficient corresponding to the wheel at the previous moment, and the larger value may be taken as the current target adhesion coefficient of the wheel, and the "take the larger" rule may be followed at subsequent moments to ensure that the target adhesion coefficient of the wheel does not decrease.

[0086] In some embodiments of the present application, by obtaining the difference in target adhesion coefficients between the wheels of the vehicle and setting a difference threshold for logical judgment, when only the maximum target adhesion coefficient difference exceeds the threshold while the other differences are less than the threshold, the wheel with abnormal adhesion coefficient (i.e., the wheel to be corrected) can be accurately identified. Subsequently, by calculating the average target adhesion coefficient of the remaining normal wheels (target wheels) and using this as a benchmark to correct the adhesion coefficient of the abnormal wheel, it can not only quickly respond to and handle the problem of uneven distribution of adhesion coefficients between wheels, avoiding vehicle instability or performance degradation caused by abnormal adhesion of a single wheel, but also ensure that the corrected adhesion coefficient meets the overall dynamic requirements of the vehicle and avoids other potential risks caused by overcorrection by introducing the average adhesion coefficient, thereby effectively improving the stability, safety, and controllability of vehicle driving.

[0087] Based on the above embodiments, please refer to Figure 9 , in one exemplary embodiment provided by the present application, the implementation process of determining the correction parameter corresponding to the second longitudinal force based on real-time working condition data may further include steps S910 to S930, which are introduced in detail as follows: Step S910, determining the wheel instability state parameter based on real-time working condition data, where the wheel instability parameter includes the number of wheel slips, the wheel speed overshoot, and the wheel slip duration; Step S920, determining the correction parameter corresponding to the second longitudinal force based on any one or more of the number of wheel slips, the wheel speed overshoot, and the wheel slip time; Step S930, where the correction parameter is positively correlated with the number of wheel slips, the wheel speed overshoot, and the wheel slip duration.

[0088] Exemplarily, relevant sensors (such as wheel speed sensors) can be used to obtain data such as the wheel speed and acceleration of each wheel in real time, and determine whether each wheel is in a slipping state (such as the wheel speed exceeding the threshold or being significantly different from the reference vehicle speed), and count the number of slipping wheels. For the slipping wheels, calculate the difference between the actual wheel speed and the ideal wheel speed (based on the vehicle reference speed) to reflect the severity of the slip, and the duration from the start of the slip to the recovery of stability to reflect the duration of the slip. Among them, the number of wheel slips, the wheel speed overshoot, and the wheel slip duration all reflect the instability degree of the vehicle, but their importance is different. For example, the correction parameter corresponding to the second longitudinal force has the highest positive correlation with the number of wheel slips (directly affecting vehicle stability), followed by the wheel speed overshoot (reflecting the severity of the slip), and finally the wheel slip duration (reflecting the duration of the slip, but may have less impact due to the recovery strategy).

[0089] Optionally, as shown in Table 4, a positive correlation between the instability factors of the wheels (such as the number of wheel slips, the wheel slip time, and the wheel speed overshoot) and the correction parameters can be established in advance and mapped to the corresponding numerical relationship.

[0090] Table 4 Optionally, by synthesizing the above Tables 1-4, the following Table 5 can be obtained. During the vehicle operation, when the vehicle is traveling on a uniform road surface, the correction parameters corresponding to the second longitudinal force and the weighting coefficients corresponding to the first longitudinal force can be determined according to Table 5 below, and then the target adhesion coefficient of the wheel can be obtained.

[0091] Table 5 If the factors in the above Table 5 appear simultaneously, the weighting coefficient corresponding to the first longitudinal force can be determined by calculating the corresponding average value, and the correction coefficient corresponding to the second longitudinal force can be determined by calculating the corresponding average value, and then the target adhesion coefficient of the wheel can be calculated.

[0092] In some embodiments of the present application, the wheel instability state parameters including the number of wheel slips, the wheel speed overshoot, and the slip duration are determined through real-time working condition data, and the correction parameters of the second longitudinal force are determined based on one or more of them. At the same time, the positive correlation degree between each parameter and the correction parameter is reasonably set, which can comprehensively consider various wheel instability factors, more accurately reflect the abnormal state of the wheels during vehicle driving, and then timely and targeted adjust the correction parameters, effectively improving the vehicle's ability to cope with wheel instability under complex working conditions, enhancing driving stability and safety, and optimizing the vehicle's handling performance.

[0093] Further, based on the above embodiments, please refer to Figure 10 , in one exemplary embodiment provided by the present application, the specific implementation process of the above adhesion coefficient determination method may further include steps S1010 to S1030, which are introduced in detail as follows: Step S1010, if the wheel slip ratio is greater than the preset slip ratio threshold, re-determine the basic adhesion coefficient of the wheel; Step S1020, obtain the number of wheel slips of the vehicle within a preset time period; Step S1030, if the number of wheel slips is greater than the preset number of wheel slip threshold and the wheel slip ratio is greater than the preset slip ratio threshold, update the basic adhesion coefficient of each wheel.

[0094] Exemplarily, the wheel speeds of each wheel, the actual vehicle speed, and the overall motion state of the vehicle can be obtained. For each slipping wheel, its slip ratio is calculated, where the slip ratio = (vehicle reference speed - actual wheel speed) / vehicle reference speed × 100%. Here, the vehicle reference speed refers to the forward speed of the vehicle under ideal conditions (i.e., no wheel slip). Then, a slip ratio threshold is preset (for example, slip ratio > 20%) to identify severe slipping conditions.

[0095] Optionally, the wheel speeds of each wheel and the overall motion state of the vehicle can also be obtained in real time through sensors such as wheel speed sensors. For each wheel, the difference between its actual wheel speed and the ideal wheel speed based on the vehicle reference speed is calculated. If the difference exceeds a preset slipping threshold (such as the wheel speed is significantly higher than the reference speed), it is determined that the wheel is in a slipping state. Within a preset time period (for example, 1 second), the number of wheels in a slipping state is continuously counted. For example, if 2 or more wheels out of 4 wheels continuously slip within 1 second, it is recorded as the number of slipping wheels ≥ 2. According to the vehicle dynamics characteristics and control requirements, a quantity threshold is preset (for example, the number of slipping wheels ≥ 2). If the number of slipping wheels reaches or exceeds the preset quantity threshold within the preset time period, and the slip ratios of all slipping wheels exceed the preset slip ratio threshold, then the next step is to re-determine the base adhesion coefficient to update the base adhesion coefficient of the wheels. The detailed implementation process of the determination scheme of the base adhesion coefficient can be found in the descriptions of the foregoing various embodiments, and will not be elaborated here.

[0096] In some embodiments of the present application, by statistically counting the number of slipping wheels within a preset time period based on real-time working condition data, when the number exceeds the preset threshold, the slip ratios of the slipping wheels are further obtained. If the slip ratios all exceed the preset threshold, the base adhesion coefficient of the wheels is re-determined. By multi-level condition judgment, the severe slipping condition of the vehicle can be accurately captured, and the base adhesion coefficient can be re-evaluated in a timely manner, which can effectively cope with the large-area severe slipping of the vehicle under complex road conditions, improve the accuracy of the adhesion coefficient estimation, provide a more reliable basis for vehicle control, and enhance the driving stability and safety of the vehicle.

[0097] Such as Figure 11As shown, the exemplary adhesion coefficient determination device 1100 includes: an acquisition module 1110 for acquiring the wheel-end torque, wheel angular acceleration, wheel slip ratio, and wheel vertical load of the vehicle; a first determination module 1120 for determining the first longitudinal force of each wheel based on the wheel-end torque and the wheel angular acceleration; a second determination module 1130 for determining the basic adhesion coefficient of each wheel based on the first longitudinal force and the wheel vertical load; a third determination module 1140 for determining the second longitudinal force of each wheel based on the wheel slip ratio and the tire model corresponding to the wheel; and a correction module 1150 for, if the basic adhesion coefficient is less than a preset adhesion coefficient threshold, correcting the basic adhesion coefficient with the second longitudinal force to obtain the target adhesion coefficient of each wheel.

[0098] According to one aspect of the embodiments of the present application, the above-mentioned correction module 1150 is further configured to obtain the road surface type where the vehicle is located; if the road surface type is characterized as a uniform road surface, obtain the real-time working condition data of the vehicle; determine the correction parameter corresponding to the second longitudinal force based on the real-time working condition data, so as to correct the basic adhesion coefficient with the correction parameter and the second longitudinal force to obtain the target adhesion coefficient of each wheel.

[0099] According to one aspect of the embodiments of the present application, the above-mentioned correction module 1150 is further configured to determine the weighting parameter corresponding to the first longitudinal force according to the correction parameter, and the sum of the weighting parameter and the correction parameter is 1; correct the second longitudinal force according to the correction parameter to obtain the corrected second longitudinal force; and obtain the target adhesion coefficient of each wheel according to the weighting parameter, the corrected second longitudinal force, and the basic adhesion coefficient.

[0100] According to one aspect of the embodiments of the present application, the above-mentioned correction module 1150 is further configured to determine the throttle opening value of the vehicle based on the real-time working condition data; if the throttle pedal opening value is greater than a preset throttle pedal opening value, determine the correction parameter corresponding to the second longitudinal force based on the throttle opening value, where the correction parameter has a positive correlation with the throttle opening value.

[0101] According to one aspect of the embodiments of the present application, the above-mentioned correction module 1150 is further configured to determine the single-wheel torque change rate of the vehicle based on the real-time working condition data; if the single-wheel torque change rate is greater than a preset torque change rate threshold, determine the correction parameter corresponding to the second longitudinal force based on the single-wheel torque change rate, and the positive correlation between the correction parameter and the single-wheel torque change rate is greater than the positive correlation between the correction parameter and the throttle opening value.

[0102] According to one aspect of the embodiments of the present application, the above-mentioned correction module 1150 is further configured to determine the difference in basic adhesion coefficients between each wheel based on real-time working condition data, where the difference in basic adhesion coefficients includes the maximum difference in basic adhesion coefficients between the maximum basic adhesion coefficient and the minimum basic adhesion coefficient among each wheel; determine the correction parameter corresponding to the second longitudinal force based on the maximum difference in basic adhesion coefficients, and the correction parameter has a positive correlation with the maximum difference in basic adhesion coefficients.

[0103] According to one aspect of the embodiments of the present application, the above-mentioned correction module 1150 is further configured to obtain the target adhesion coefficient difference between each wheel, where the target adhesion coefficient difference includes the maximum target adhesion coefficient difference between the maximum target adhesion coefficient and the minimum target adhesion coefficient among each wheel; if the maximum target adhesion coefficient difference is greater than the preset difference threshold and the remaining target adhesion coefficient differences are all less than the preset difference threshold, then determine the wheel to be corrected based on the maximum target adhesion coefficient difference; determine the average target adhesion coefficient corresponding to the target wheels of the vehicle, where the target wheels are the other wheels of the vehicle except the wheel to be corrected, and correct the target adhesion coefficient of the wheel to be corrected based on the average target adhesion coefficient.

[0104] According to one aspect of the embodiments of the present application, the above-mentioned correction module 1150 is further configured to determine the wheel instability state parameter based on real-time working condition data, where the wheel instability parameter includes the number of wheel slips, the wheel speed overshoot, and the wheel slip duration; determine the correction parameter corresponding to the second longitudinal force based on any one or more of the number of wheel slips, the wheel speed overshoot, and the wheel slip duration; where the correction parameter has a positive correlation with the number of wheel slips, the wheel speed overshoot, and the wheel slip duration.

[0105] According to one aspect of the embodiments of the present application, the above-mentioned second determination module 1130 is further configured to, if the wheel slip ratio is greater than the preset slip ratio threshold, re-determine the basic adhesion coefficient of the wheel; obtain the number of wheel slips of the vehicle within a preset duration; if the number of wheel slips is greater than the preset number of wheel slips threshold and the wheel slip ratio is greater than the preset slip ratio threshold, then update the basic adhesion coefficients of each wheel.

[0106] It should be noted that the adhesion coefficient determination device provided in the above embodiments and the determination method provided in the above embodiments belong to the same concept. The specific manners in which each module and unit perform operations have been described in detail in the method embodiments and will not be repeated here. In practical applications, the adhesion coefficient determination device provided in the above embodiments can, according to needs, allocate the above functions to different functional modules, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here either.

[0107] Embodiments of the present application also provide an electronic device, including: one or more processors; a storage device for storing one or more programs, which, when executed by the one or more processors, cause the electronic device to implement the determination methods provided in the above various embodiments.

[0108] Figure 12 FIG. shows a schematic structural diagram of a computer system of an electronic device suitable for implementing embodiments of the present application. It should be noted that, Figure 12 The illustrated computer system 1200 of the electronic device is only an example and should not impose any limitation on the functions and usage scope of the embodiments of the present application.

[0109] As Figure 12 shown, the computer system 1200 includes a central processing unit (CPU) 1201, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 1202 or the program loaded from the storage section 1208 into the random access memory (RAM) 1203, such as executing the methods in the above embodiments. In the RAM 1203, various programs and data required for system operation are also stored. The CPU 1201, ROM 1202, and RAM 1203 are connected to each other via a bus 1204. The input / output (I / O) interface 1205 is also connected to the bus 1204.

[0110] The following components are connected to the I / O interface 1205: an input section 1206 including a keyboard, a mouse, etc.; an output section 1207 including, for example, a cathode ray tube (CRT), a liquid crystal display (LCD), etc. and a speaker, etc.; a storage section 1208 including a hard disk, etc.; and a communication section 1209 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 1209 performs communication processing via a network such as the Internet. A drive 1210 is also connected to the I / O interface 1205 as required. A removable medium 1211, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1210 as required so that the computer program read from it can be installed into the storage section 1208 as required.

[0111] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 1209, and / or installed from the removable medium 1211. When the computer program is executed by the central processing unit (CPU) 1201, various functions defined in the system of the present application are executed.

[0112] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. The computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium 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), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable computer program. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, and the computer-readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The computer program included on the computer-readable medium can be transmitted by any suitable medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0113] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present application. Among them, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above-mentioned module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, as well as the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0114] The units involved in the embodiments described in the present application can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these units do not constitute a limitation to the units themselves in some cases.

[0115] Another aspect of the present application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the determination method as described above is implemented. The computer-readable storage medium may be included in the electronic device described in the above embodiments, or may exist separately without being assembled into the electronic device.

[0116] Another aspect of the present application also provides a computer program product or a computer program, and the computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the determination methods provided in the above various embodiments.

[0117] The above content is only a preferred exemplary embodiment of the present application and is not used to limit the implementation of the present application. Those of ordinary skill in the art can easily make corresponding adaptations or modifications according to the main concepts and spirits of the present application. Therefore, the protection scope of the present application should be subject to the protection scope required by the claims.

Claims

1. A method for determining adhesion coefficient, characterized in that, The determination method includes: Obtaining the wheel-end torque, wheel angular acceleration, wheel slip ratio, and wheel vertical load of the vehicle; Determining the first longitudinal force of each wheel based on the wheel-end torque and the wheel angular acceleration; Determining the basic adhesion coefficient of each wheel based on the first longitudinal force and the wheel vertical load; Determining the second longitudinal force of each wheel based on the wheel slip ratio and the tire model corresponding to the wheel; If the basic adhesion coefficient is less than a preset adhesion coefficient threshold, then the second longitudinal force is used to correct the basic adhesion coefficient to obtain the target adhesion coefficient of each wheel.

2. The determination method according to claim 1, wherein The step of using the second longitudinal force to correct the basic adhesion coefficient to obtain the target adhesion coefficient of each wheel includes: Obtaining the road surface type where the vehicle is located; If the road surface type is characterized as a uniform road surface, then obtaining the real-time working condition data of the vehicle; Determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data, so as to correct the basic adhesion coefficient based on the correction parameter and the second longitudinal force to obtain the target adhesion coefficient of each wheel.

3. The determination method according to claim 2, characterized in that, The step of determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data, so as to correct the basic adhesion coefficient based on the correction parameter and the second longitudinal force to obtain the target adhesion coefficient of each wheel includes: Determining the weighting parameter corresponding to the first longitudinal force according to the correction parameter, and the sum of the weighting parameter and the correction parameter is 1; Correcting the second longitudinal force according to the correction parameter to obtain the corrected second longitudinal force; Obtaining the target adhesion coefficient of each wheel according to the weighting parameter, the corrected second longitudinal force, and the basic adhesion coefficient.

4. The determination method according to claim 2, wherein The step of determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data includes: Determining the throttle opening value of the vehicle based on the real-time working condition data; If the throttle pedal opening value is greater than a preset throttle pedal opening value, then determining the correction parameter corresponding to the second longitudinal force based on the throttle opening value, where the correction parameter has a positive correlation with the throttle opening value.

5. The determination method according to claim 4, wherein The step of determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data includes: Determining the single-wheel torque change rate of the vehicle based on the real-time working condition data; If the single-wheel torque change rate is greater than a preset torque change rate threshold, then determining the correction parameter corresponding to the second longitudinal force based on the single-wheel torque change rate, and the positive correlation between the correction parameter and the single-wheel torque change rate is greater than the positive correlation between the correction parameter and the throttle opening value.

6. The determination method according to claim 2, wherein The step of determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data includes: Determining the difference in the basic adhesion coefficient between each wheel based on the real-time working condition data, where the difference in the basic adhesion coefficient between each wheel includes the maximum difference in the basic adhesion coefficient between the maximum basic adhesion coefficient and the minimum basic adhesion coefficient among each wheel; Determining the correction parameter corresponding to the second longitudinal force based on the maximum difference in the basic adhesion coefficient, and the correction parameter has a positive correlation with the maximum difference in the basic adhesion coefficient.

7. The determination method according to any one of claims 1 to 6, characterized in that, The determination method further includes: Obtaining a target adhesion coefficient difference between each wheel, where the target adhesion coefficient difference includes a maximum target adhesion coefficient difference between the maximum target adhesion coefficient and the minimum target adhesion coefficient among each wheel; If the maximum target adhesion coefficient difference is greater than a preset difference threshold and the remaining target adhesion coefficient differences are all less than the preset difference threshold, determining a wheel to be corrected based on the maximum target adhesion coefficient difference; Determining an average target adhesion coefficient corresponding to a target wheel of the vehicle, where the target wheel is other wheels of the vehicle except the wheel to be corrected, and correcting the target adhesion coefficient of the wheel to be corrected based on the average target adhesion coefficient.

8. The determination method according to claim 2, wherein The determining the correction parameter corresponding to the second longitudinal force based on the real-time working condition data includes: Determining a wheel instability state parameter based on the real-time working condition data, where the wheel instability parameter includes the number of wheel slips, the wheel speed overshoot, and the wheel slip duration; Determining the correction parameter corresponding to the second longitudinal force based on any one or more of the number of wheel slips, the wheel speed overshoot, and the wheel slip duration; Wherein, the correction parameter is positively correlated with the number of wheel slips, the wheel speed overshoot, and the wheel slip duration.

9. The determination method according to claim 1, characterized in that The determination method further includes: If the wheel slip ratio is greater than a preset slip ratio threshold, re-determining the basic adhesion coefficient of the wheel; Obtaining the number of wheel slips of the vehicle within a preset time period; If the number of wheel slips is greater than a preset number of wheel slip threshold and the wheel slip ratio is greater than a preset slip ratio threshold, updating the basic adhesion coefficient of each wheel.

10. An adhesion coefficient determination device, characterized in that, The determination device includes: An acquisition module, configured to acquire the wheel end torque, wheel angular acceleration, wheel slip ratio, and wheel vertical load of the vehicle; A first determination module, configured to determine a first longitudinal force of each wheel based on the wheel end torque and the wheel angular acceleration; A second determination module, configured to determine the basic adhesion coefficient of each wheel based on the first longitudinal force and the wheel vertical load; A third determination module, configured to determine a second longitudinal force of each wheel based on the wheel slip ratio and the tire model corresponding to the wheel; A correction module, configured to, if the basic adhesion coefficient is less than a preset adhesion coefficient threshold, correct the basic adhesion coefficient by using the second longitudinal force to obtain the target adhesion coefficient of each wheel.

11. An electronic device, characterized in that, Including: One or more processors; A storage device, configured to store one or more programs, which when executed by the one or more processors, cause the electronic device to implement the determination method according to any one of claims 1 to 9.

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