Method and device for determining longitudinal adhesion coefficient, vehicle, medium and program product

Abstract

A method and device (50) for determining a longitudinal adhesion coefficient, a vehicle (60), a medium and a program product. The method comprises: determining a longitudinal adhesion coefficient of each wheel on the basis of first wheel information and a plurality of scenario adhesion coefficients of each wheel, the first wheel information comprising a longitudinal stiffness, a slip rate, and a nominal longitudinal force (S201); on the basis of the longitudinal adhesion coefficients of a plurality of wheels, determining a first longitudinal adhesion coefficient and a first confidence of a vehicle in a low adhesion state, and a second longitudinal adhesion coefficient and a second confidence of the vehicle in a high adhesion state (S202); and determining a longitudinal adhesion coefficient of the vehicle on the basis of the first longitudinal adhesion coefficient, the first confidence, the second longitudinal adhesion coefficient and the second confidence (S203), thereby improving the accuracy of determining the longitudinal adhesion coefficient of the vehicle.

Description

Method, device, vehicle, medium and program product for determining longitudinal adhesion coefficient

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 15, 2024, with application number 202410301421.1 and application name “Method, device, vehicle, medium and program product for determining longitudinal adhesion coefficient”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to, but are not limited to, the field of vehicle technology, and in particular to a method, device, vehicle, medium, and program product for determining a longitudinal adhesion coefficient. Background Art

[0003] The vehicle's adhesion coefficient plays a key role in the vehicle's longitudinal drive anti-skid control. Therefore, accurately determining the vehicle's adhesion coefficient is crucial for the vehicle's anti-skid control. Summary of the Invention

[0004] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0005] The embodiments of the present application provide a method, apparatus, vehicle, medium, and program product for determining a longitudinal adhesion coefficient, which can improve the accuracy of determining the longitudinal adhesion coefficient of a vehicle.

[0006] In a first aspect, an embodiment of the present application provides a method for determining a longitudinal adhesion coefficient, comprising:

[0007] determining a longitudinal adhesion coefficient of each wheel based on first wheel information of each wheel and a plurality of scenario adhesion coefficients, wherein the first wheel information includes longitudinal stiffness, slip ratio, and normalized longitudinal force;

[0008] determining, based on the longitudinal adhesion coefficients of the plurality of wheels, a first longitudinal adhesion coefficient and a first confidence level of the vehicle in a low adhesion state, and a second longitudinal adhesion coefficient and a second confidence level of the vehicle in a high adhesion state;

[0009] A longitudinal adhesion coefficient of the vehicle is determined based on the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level.

[0010] In one implementation, determining the longitudinal adhesion coefficient of each wheel according to the first wheel information of each wheel and the plurality of scenario adhesion coefficients includes:

[0011] For any wheel, determine the probability corresponding to each scene adhesion coefficient based on the first wheel information of the wheel and multiple scene adhesion coefficients;

[0012] The longitudinal adhesion coefficient of the wheel is determined according to the probability corresponding to each scene adhesion coefficient and the multiple scene adhesion coefficients.

[0013] In one implementation, determining a first longitudinal adhesion coefficient and a first confidence level of a vehicle in a low-adhesion state based on longitudinal adhesion coefficients of a plurality of wheels includes:

[0014] Obtain the activation duration of the stability control system and the rate of change of longitudinal acceleration;

[0015] Get the slip ratio deviation of each wheel;

[0016] For any wheel, if multiple low-adhesion estimation conditions are met, determining whether the wheel satisfies a first condition or a second condition based on the wheel slip ratio deviation and the normalized longitudinal force of the wheel;

[0017] Determining a first longitudinal adhesion coefficient and a first confidence level based on the number of wheels that meet the first condition, the number of wheels that meet the second condition, the longitudinal adhesion coefficient and the confidence level of each wheel that meets the first condition, and the longitudinal adhesion coefficient and the confidence level of each wheel that meets the second condition;

[0018] Among them, multiple low-attachment estimation conditions include:

[0019] The longitudinal adhesion coefficient of the wheel is greater than the first threshold, the estimated flag of the wheel is a valid flag, the activation time is greater than the second threshold, and the longitudinal acceleration change rate is less than the third threshold.

[0020] In one implementation, determining whether a wheel satisfies a first condition or a second condition based on a slip ratio deviation of the wheel and a normalized longitudinal force of the wheel includes:

[0021] If the slip ratio deviation of the wheel is greater than the first deviation threshold and less than or equal to the second deviation threshold, and the normalized longitudinal force of the wheel is greater than the first longitudinal force threshold, then determining that the wheel satisfies the first condition;

[0022] If the slip ratio deviation of the wheel is greater than the second deviation threshold, and the normalized longitudinal force of the wheel is greater than the first longitudinal force threshold, the wheel is determined to be a wheel that meets the second condition.

[0023] In one implementation, determining a second longitudinal adhesion coefficient and a second confidence level of the vehicle in a high adhesion state based on longitudinal adhesion coefficients of a plurality of wheels includes:

[0024] Get the activation time of the stability control system;

[0025] For any wheel, if multiple high-adhesion estimation conditions are met, determining whether the wheel satisfies the third condition or the fourth condition based on the normalized longitudinal force of the wheel;

[0026] determining a second longitudinal adhesion coefficient and a second confidence level based on the number of wheels that meet the third condition, the number of wheels that meet the fourth condition, the longitudinal adhesion coefficient and the confidence level of each wheel that meets the third condition, and the longitudinal adhesion coefficient and the confidence level of each wheel that meets the fourth condition;

[0027] Among them, multiple high-attachment estimation conditions include:

[0028] The longitudinal adhesion coefficient of the wheel is greater than the fourth threshold, the estimated flag position of the wheel is a valid flag position, and the activation time is greater than the fifth threshold.

[0029] In one implementation, determining whether a wheel satisfies the third condition or the fourth condition based on the normalized longitudinal force of the wheel includes:

[0030] If the normalized longitudinal force of the wheel is greater than the second longitudinal force threshold and less than or equal to the third longitudinal force threshold, determining that the wheel is a wheel that meets the third condition;

[0031] If the normalized longitudinal force of the wheel is greater than the third longitudinal force threshold, the wheel is determined to be a wheel that meets the fourth condition.

[0032] In one implementation, determining the longitudinal adhesion coefficient of the vehicle according to the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level includes:

[0033] Determine the adhesion coefficient variance corresponding to each wheel based on the longitudinal adhesion coefficient of the wheel, the probability corresponding to each scene adhesion coefficient, and the adhesion coefficients of multiple scenes;

[0034] Determining a scene adhesion coefficient variance of the vehicle according to scene adhesion coefficient variances corresponding to a plurality of wheels;

[0035] When the scene adhesion coefficient variance of the vehicle is less than the variance threshold, if the first confidence level is greater than or equal to the second confidence level, determining the first longitudinal adhesion coefficient as the longitudinal adhesion coefficient;

[0036] If the first confidence level is less than the second confidence level, determining the second longitudinal adhesion coefficient as the longitudinal adhesion coefficient;

[0037] When the scene adhesion coefficient variance of the vehicle is greater than or equal to the variance threshold, the preset longitudinal adhesion coefficient is determined as the longitudinal adhesion coefficient.

[0038] In one implementation, determining the scene adhesion coefficient variance of the vehicle based on the scene adhesion coefficient variances corresponding to the plurality of wheels includes:

[0039] For any wheel, determining a variance correction coefficient based on first wheel information and second wheel information of the wheel; the second wheel information includes: tire torque, acceleration fluctuation value, longitudinal vehicle speed quality factor, Euler angle, longitudinal vehicle speed, and / or load;

[0040] According to the variance correction coefficient, the adhesion coefficient variance corresponding to the wheel is corrected to obtain the corrected variance;

[0041] Accumulating the reciprocals of the correction variances of the multiple wheels to obtain a first accumulated value;

[0042] The reciprocal of the first accumulated value is determined as the scene adhesion coefficient variance of the vehicle.

[0043] In one implementation, determining the longitudinal adhesion coefficient of each wheel according to the first wheel information of each wheel and the plurality of scenario adhesion coefficients includes:

[0044] determining a longitudinal adhesion coefficient of each wheel based on first wheel information of each wheel and a plurality of scenario adhesion coefficients when the vehicle satisfies any one or more longitudinal estimation conditions of the plurality of longitudinal estimation conditions;

[0045] Among them, multiple longitudinal estimation conditions include:

[0046] The vehicle's speed is within a preset range;

[0047] The vehicle's acceleration is less than or equal to the acceleration threshold;

[0048] The vehicle's angular velocity is less than or equal to the angular velocity threshold;

[0049] The duration for which the vehicle's steering wheel angle is greater than the angle threshold is less than or equal to a preset duration;

[0050] The signal state of the vehicle's sensor signal is normal;

[0051] The vehicle's stability control system is activated.

[0052] In a second aspect, an embodiment of the present application provides a device for determining a longitudinal adhesion coefficient, comprising:

[0053] a processing module configured to determine a longitudinal adhesion coefficient of each wheel based on first wheel information of each wheel and a plurality of scenario adhesion coefficients, wherein the first wheel information includes longitudinal stiffness, slip ratio, and normalized longitudinal force;

[0054] The processing module is further configured to determine, based on the longitudinal adhesion coefficients of the plurality of wheels, a first longitudinal adhesion coefficient and a first confidence level of the vehicle in a low adhesion state, and a second longitudinal adhesion coefficient and a second confidence level of the vehicle in a high adhesion state;

[0055] The fusion module is configured to determine a longitudinal adhesion coefficient of the vehicle based on the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level.

[0056] In one implementation, the processing module is specifically configured to:

[0057] For any wheel, determine the probability corresponding to each scene adhesion coefficient based on the first wheel information of the wheel and multiple scene adhesion coefficients;

[0058] The longitudinal adhesion coefficient of the wheel is determined according to the probability corresponding to each scene adhesion coefficient and the multiple scene adhesion coefficients.

[0059] In one implementation, the processing module is specifically configured to:

[0060] Obtain the activation duration of the stability control system and the rate of change of longitudinal acceleration;

[0061] Get the slip ratio deviation of each wheel;

[0062] For any wheel, if multiple low-adhesion estimation conditions are met, determining whether the wheel satisfies a first condition or a second condition based on the wheel slip ratio deviation and the normalized longitudinal force of the wheel;

[0063] Determining a first longitudinal adhesion coefficient and a first confidence level based on the number of wheels that meet the first condition, the number of wheels that meet the second condition, the longitudinal adhesion coefficient and the confidence level of each wheel that meets the first condition, and the longitudinal adhesion coefficient and the confidence level of each wheel that meets the second condition;

[0064] Among them, multiple low-attachment estimation conditions include:

[0065] The longitudinal adhesion coefficient of the wheel is greater than the first threshold, the estimated flag of the wheel is a valid flag, the activation time is greater than the second threshold, and the longitudinal acceleration change rate is less than the third threshold.

[0066] In one implementation, the processing module is specifically configured to:

[0067] If the slip ratio deviation of the wheel is greater than the first deviation threshold and less than or equal to the second deviation threshold, and the normalized longitudinal force of the wheel is greater than the first longitudinal force threshold, then determining that the wheel satisfies the first condition;

[0068] If the slip ratio deviation of the wheel is greater than the second deviation threshold, and the normalized longitudinal force of the wheel is greater than the first longitudinal force threshold, the wheel is determined to be a wheel that meets the second condition.

[0069] In one implementation, the processing module is specifically configured to:

[0070] Get the activation time of the stability control system;

[0071] For any wheel, if multiple high-adhesion estimation conditions are met, determining whether the wheel satisfies the third condition or the fourth condition based on the normalized longitudinal force of the wheel;

[0072] determining a second longitudinal adhesion coefficient and a second confidence level based on the number of wheels that meet the third condition, the number of wheels that meet the fourth condition, the longitudinal adhesion coefficient and the confidence level of each wheel that meets the third condition, and the longitudinal adhesion coefficient and the confidence level of each wheel that meets the fourth condition;

[0073] Among them, multiple high-attachment estimation conditions include:

[0074] The longitudinal adhesion coefficient of the wheel is greater than the fourth threshold, the estimated flag position of the wheel is a valid flag position, and the activation time is greater than the fifth threshold.

[0075] In one implementation, the processing module is specifically configured to:

[0076] If the normalized longitudinal force of the wheel is greater than the second longitudinal force threshold and less than or equal to the third longitudinal force threshold, determining that the wheel is a wheel that meets the third condition;

[0077] If the normalized longitudinal force of the wheel is greater than the third longitudinal force threshold, the wheel is determined to be a wheel that meets the fourth condition.

[0078] In one implementation, the fusion module is specifically configured to:

[0079] Determine the adhesion coefficient variance corresponding to each wheel based on the longitudinal adhesion coefficient of the wheel, the probability corresponding to each scene adhesion coefficient, and the adhesion coefficients of multiple scenes;

[0080] Determining a scene adhesion coefficient variance of the vehicle according to scene adhesion coefficient variances corresponding to a plurality of wheels;

[0081] When the scene adhesion coefficient variance of the vehicle is less than the variance threshold, if the first confidence level is greater than or equal to the second confidence level, determining the first longitudinal adhesion coefficient as the longitudinal adhesion coefficient;

[0082] If the first confidence level is less than the second confidence level, determining the second longitudinal adhesion coefficient as the longitudinal adhesion coefficient;

[0083] When the scene adhesion coefficient variance of the vehicle is greater than or equal to the variance threshold, the preset longitudinal adhesion coefficient is determined as the longitudinal adhesion coefficient.

[0084] In one implementation, the fusion module is specifically configured to:

[0085] For any wheel, determining a variance correction coefficient based on first wheel information and second wheel information of the wheel; the second wheel information includes: tire torque, acceleration fluctuation value, longitudinal vehicle speed quality factor, Euler angle, longitudinal vehicle speed, and / or load;

[0086] According to the variance correction coefficient, the adhesion coefficient variance corresponding to the wheel is corrected to obtain the corrected variance;

[0087] Accumulating the reciprocals of the correction variances of the multiple wheels to obtain a first accumulated value;

[0088] The reciprocal of the first accumulated value is determined as the scene adhesion coefficient variance of the vehicle.

[0089] In one implementation, the processing module is specifically configured to:

[0090] determining a longitudinal adhesion coefficient of each wheel based on first wheel information of each wheel and a plurality of scenario adhesion coefficients when the vehicle satisfies any one or more longitudinal estimation conditions of the plurality of longitudinal estimation conditions;

[0091] Among them, multiple longitudinal estimation conditions include:

[0092] The vehicle's speed is within a preset range;

[0093] The vehicle's acceleration is less than or equal to the acceleration threshold;

[0094] The vehicle's angular velocity is less than or equal to the angular velocity threshold;

[0095] The duration for which the vehicle's steering wheel angle is greater than the angle threshold is less than or equal to a preset duration;

[0096] The signal state of the vehicle's sensor signal is normal;

[0097] The vehicle's stability control system is activated.

[0098] In a third aspect, an embodiment of the present application provides a vehicle, comprising:

[0099] a processor, and a memory communicatively coupled to the processor;

[0100] a memory configured to store computer-executable instructions;

[0101] The processor is configured to execute computer-executable instructions stored in the memory to implement the method for determining the longitudinal adhesion coefficient of the first aspect.

[0102] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are configured to implement the method for determining the longitudinal adhesion coefficient of the first aspect.

[0103] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program, which, when executed by a processor, is used to implement the method for determining the longitudinal adhesion coefficient as in the first aspect.

[0104] Embodiments of the present application provide a method, apparatus, vehicle, medium, and program product for determining a longitudinal adhesion coefficient. In this method, a vehicle can determine the longitudinal adhesion coefficient of each wheel based on first wheel information and multiple scenario adhesion coefficients for each wheel; the first wheel information includes longitudinal stiffness, slip rate, and normalized longitudinal force. Based on the longitudinal adhesion coefficients of the multiple wheels, the vehicle can determine a first longitudinal adhesion coefficient and a first confidence level for the vehicle in a low-adhesion state, as well as a second longitudinal adhesion coefficient and a second confidence level for the vehicle in a high-adhesion state. The vehicle can determine the longitudinal adhesion coefficient of the vehicle based on the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level. Through the above-described method, the longitudinal adhesion coefficient can be accurately determined, thereby improving the accuracy of determining the vehicle's longitudinal adhesion coefficient, thereby improving the vehicle's controllability under driving conditions and enhancing the safety of passengers.

[0105] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0106] The drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0107] FIG1 is a schematic diagram of an application scenario applicable to an embodiment of the present application;

[0108] FIG2 a is a flow chart of a method for determining a longitudinal adhesion coefficient according to a first embodiment of the present application;

[0109] FIG2 b is a schematic diagram of a hyperbolic tangent fitting curve provided in an embodiment of the present application;

[0110] FIG3 a is a flow chart of a second embodiment of a method for determining a longitudinal adhesion coefficient provided in an embodiment of the present application;

[0111] FIG3 b is a schematic diagram of a process for analyzing a wheel according to an embodiment of the present application;

[0112] FIG4 a is a flow chart of a third embodiment of a method for determining a longitudinal adhesion coefficient provided in an embodiment of the present application;

[0113] FIG4 b is a schematic diagram of another process for analyzing a wheel according to an embodiment of the present application;

[0114] FIG5 is a schematic structural diagram of a device for determining a longitudinal adhesion coefficient according to an embodiment of the present application;

[0115] FIG6 is a structural diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0116] The described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments made by ordinary technicians in this field under the inspiration of these embodiments are within the scope of protection of this application.

[0117] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the numbers used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0118] A vehicle's longitudinal adhesion coefficient plays a key role in implementing longitudinal anti-skid control. Typically, the longitudinal adhesion coefficient is estimated directly based on the ratio of longitudinal driving force to vertical load, and anti-skid control is implemented based on this longitudinal adhesion coefficient. However, this method of estimating the longitudinal adhesion coefficient directly based on the ratio of longitudinal driving force to vertical load suffers from inconsistencies between the estimated longitudinal adhesion coefficient and the actual longitudinal adhesion coefficient of the vehicle during operation, leading to inaccurate anti-skid control and compromising passenger safety.

[0119] An embodiment of the present application provides a method for determining a longitudinal adhesion coefficient. A vehicle can determine the longitudinal adhesion coefficient of each wheel based on first wheel information and multiple scenario adhesion coefficients for each wheel; the first wheel information includes longitudinal stiffness, slip rate, and normalized longitudinal force. The vehicle can determine a first longitudinal adhesion coefficient and a first confidence level for the vehicle in a low-adhesion state, and a second longitudinal adhesion coefficient and a second confidence level for the vehicle in a high-adhesion state based on the longitudinal adhesion coefficients of the multiple wheels. The vehicle can determine the longitudinal adhesion coefficient of the vehicle based on the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level. Through the above method, the longitudinal adhesion coefficient can be accurately determined, improving the accuracy of determining the vehicle's longitudinal adhesion coefficient, thereby improving the vehicle's controllability under driving conditions and enhancing the safety of passengers.

[0120] The principles and features of the embodiments of the present application are described below in conjunction with the accompanying drawings. The examples given are only used to explain the embodiments of the present application and are not used to limit the scope of the embodiments of the present application.

[0121] FIG1 is a schematic diagram of an application scenario applicable to an embodiment of the present application. The application scenario includes a vehicle 10, which includes multiple wheels. For example, FIG1 shows four wheels, namely a left front wheel 101, a right front wheel 102, a left rear wheel 103, and a right rear wheel 104.

[0122] In one implementation, multiple sensors (not shown in FIG1 ) may be installed on the vehicle 10 . It should be noted that the multiple sensors may include a wheel speed sensor, an inertial measurement unit (IMU) sensor, and a wheel angle sensor.

[0123] In one implementation, the vehicle 10 may also be deployed with a stability control system (not shown in FIG. 1 ).

[0124] It should be noted that stability control systems include, but are not limited to, anti-lock braking systems, anti-skid systems, traction control systems, automatic driving systems, automatic avoidance control systems, and other systems that operate based on information related to the rotation of one or more wheels (tires) of the vehicle (for example, information about the relative rotation of two or more wheels (tires)).

[0125] In this application scenario, vehicle 10 can determine the longitudinal adhesion coefficient of each wheel based on first wheel information for each wheel and multiple scenario adhesion coefficients; the first wheel information includes longitudinal stiffness, slip ratio, and normalized longitudinal force. Based on the longitudinal adhesion coefficients of the multiple wheels, vehicle 10 can determine a first longitudinal adhesion coefficient and a first confidence level for vehicle 10 in a low-adhesion state, and a second longitudinal adhesion coefficient and a second confidence level for vehicle 10 in a high-adhesion state. Vehicle 10 can determine the longitudinal adhesion coefficient of vehicle 10 based on the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level.

[0126] The embodiment of the present application does not limit the actual form of the vehicle included in Figure 1. In the application of the solution, it can be set according to actual needs.

[0127] The technical solution of the present application is described in detail below through specific embodiments. It should be noted that the following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0128] FIG2a is a flow chart of a method for determining a longitudinal adhesion coefficient according to an embodiment of the present application. Referring to FIG2a , the method specifically includes the following steps:

[0129] S201: Determine the longitudinal adhesion coefficient of each wheel according to first wheel information of each wheel and multiple scene adhesion coefficients.

[0130] In this embodiment, the vehicle can obtain first wheel information and multiple scenario adhesion coefficients for each wheel. The first wheel information includes longitudinal stiffness, slip rate, and normalized longitudinal force. It should be noted that the scenario adhesion coefficient refers to the longitudinal adhesion coefficient of the wheel under a specific road scenario.

[0131] The vehicle can determine the longitudinal adhesion coefficient of each wheel based on the first wheel information of each wheel and multiple scenario adhesion coefficients.

[0132] Specifically, in the process of determining the longitudinal adhesion coefficient of each wheel:

[0133] First, it should be noted that the numerical relationship between the longitudinal adhesion coefficient and the slip rate of the wheel satisfies the hyperbolic tangent fitting curve:

[0134] Wherein, x(i) is the longitudinal adhesion coefficient of the wheel; muelevel(i) is the scene adhesion coefficient. For example, muelevel(i) can be any value in [0.15 0.35 0.45 0.6 0.75 0.9]; k takes the values ​​of 1, 2, 3, and 4, representing the left front wheel, right front wheel, left rear wheel, and right rear wheel respectively; LongStfns(k) is the longitudinal stiffness, and Slip(k) is the slip rate.

[0135] FIG2 b is a schematic diagram of a hyperbolic tangent fitting curve provided in an embodiment of the present application.

[0136] Based on the numerical relationship between the longitudinal adhesion coefficient and slip rate of the wheel, which satisfies the hyperbolic tangent fitting curve, the vehicle can determine the probability corresponding to each scenario adhesion coefficient for any wheel based on the first wheel information of the wheel and multiple scenario adhesion coefficients. The vehicle can determine the longitudinal adhesion coefficient of the wheel based on the probability corresponding to each scenario adhesion coefficient and the multiple scenario adhesion coefficients.

[0137] For example, the vehicle may use the following formula to calculate the longitudinal adhesion coefficient of the wheel: MueInst(k)=E(X)=P(1)*0.15+P(2)*0.3+P(3)*0.45+P(4)*0.6+P(5)*0.75+P(6)*0.9

[0138] It should be noted that P(1) is the probability corresponding to the adhesion coefficient of the first scene, and 0.15 is the adhesion coefficient of the first scene; P(2) is the probability corresponding to the adhesion coefficient of the second scene, and 0.35 is the adhesion coefficient of the second scene; P(3) is the probability corresponding to the adhesion coefficient of the third scene, and 0.45 is the adhesion coefficient of the third scene; P(4) is the probability corresponding to the adhesion coefficient of the fourth scene, and 0.6 is the adhesion coefficient of the fourth scene; P(5) is the probability corresponding to the adhesion coefficient of the fifth scene, and 0.75 is the adhesion coefficient of the second scene; P(6) is the probability corresponding to the adhesion coefficient of the sixth scene, and 0.9 is the adhesion coefficient of the sixth scene.

[0139] It should also be noted that MueInst(k) is the longitudinal adhesion coefficient of the wheel, FxNorm(k) is the normalized longitudinal force, LongStfns(k) is the longitudinal stiffness, Slip(k) is the slip rate, and the values ​​of k are 1, 2, 3, and 4, representing the left front wheel, right front wheel, left rear wheel, and right rear wheel respectively.

[0140] It should also be noted that when calculating the probability corresponding to each scene adhesion coefficient, max(P) can use the initial value 1 / 6. An initial value of 1 can be used.

[0141] S202: Determine, based on the longitudinal adhesion coefficients of the plurality of wheels, a first longitudinal adhesion coefficient and a first confidence level of the vehicle in a low adhesion state, and a second longitudinal adhesion coefficient and a second confidence level of the vehicle in a high adhesion state.

[0142] In this embodiment, the vehicle may determine a first longitudinal adhesion coefficient and a first confidence level of the vehicle in a low adhesion state, and a second longitudinal adhesion coefficient and a second confidence level of the vehicle in a high adhesion state based on the longitudinal adhesion coefficients of multiple wheels.

[0143] In determining the first dynamic adhesion coefficient and the first confidence level:

[0144] The vehicle can obtain the activation time of the stability control system and the rate of change of longitudinal acceleration. The vehicle can also obtain the slip deviation of each wheel.

[0145] For any wheel, if the vehicle determines that the wheel meets multiple low-adhesion estimation conditions, the vehicle analyzes the wheel based on the wheel's slip ratio deviation and the normalized longitudinal force to determine whether the wheel meets the first condition or the second condition. The multiple low-adhesion estimation conditions include: the wheel's longitudinal adhesion coefficient is greater than a first threshold, the wheel's estimation flag is valid, the activation duration is greater than a second threshold, and the longitudinal acceleration rate of change is less than a third threshold. It should be noted that the vehicle determines the wheel's estimation flag is valid if the wheel's corresponding adhesion coefficient variance is less than a sixth threshold; and determines the wheel's estimation flag is invalid if the wheel's corresponding adhesion coefficient variance is greater than or equal to a fifth threshold. It should also be noted that the first threshold can be any value between 0 and 0.4, the third threshold can be any value between 200 milliseconds and 500 milliseconds, and the fourth threshold can be any value between 3000 and 5000.

[0146] After analyzing all wheels, the vehicle can determine the number of wheels that meet the first condition and the number of wheels that meet the second condition.

[0147] The wheels can determine the first longitudinal adhesion coefficient and the first confidence level based on the number of wheels that meet the first condition, the number of wheels that meet the second condition, the longitudinal adhesion coefficient and confidence level of each wheel that meets the first condition, and the longitudinal adhesion coefficient and confidence level of each wheel that meets the second condition.

[0148] In determining the second dynamic adhesion coefficient and the second confidence factor:

[0149] The vehicle can obtain information about how long the stability control system has been active.

[0150] For any wheel, if the vehicle determines that the wheel meets multiple high-adhesion estimation conditions, the vehicle determines whether the wheel meets the third condition or the fourth condition based on the normalized longitudinal force of the wheel. The multiple high-adhesion estimation conditions include: the wheel's longitudinal adhesion coefficient being greater than a fourth threshold, the wheel's estimation flag being in the valid position, and the activation duration being greater than a fifth threshold. It should be noted that the fourth threshold can be any value between 0.4 and 1, and the fifth threshold can be any value between 300 milliseconds and 500 milliseconds.

[0151] After analyzing all wheels, the vehicle can determine the number of wheels that meet the third condition and the number of wheels that meet the fourth condition.

[0152] The vehicle can determine the second longitudinal adhesion coefficient and the second confidence level based on the number of wheels that meet the third condition, the number of wheels that meet the fourth condition, the longitudinal adhesion coefficient and confidence level of each wheel that meets the third condition, and the longitudinal adhesion coefficient and confidence level of each wheel that meets the fourth condition.

[0153] S203: Determine the longitudinal adhesion coefficient of the vehicle according to the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level.

[0154] In this embodiment, the vehicle may determine the longitudinal adhesion coefficient of the vehicle according to the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level.

[0155] Specifically, the vehicle can determine the adhesion coefficient variance corresponding to each wheel based on the longitudinal adhesion coefficient of the wheel, the probability corresponding to each scene adhesion coefficient, and multiple scene adhesion coefficients.

[0156] For example, the vehicle can use the following formula to calculate the variance of the adhesion coefficient corresponding to each wheel: MueVarInst(k)=D(x)=p1[x1-E(X)] 2 +p2[x2-E(X)] 2 +…+p n [x n -E(X)] 2

[0157] Among them, MueVarInst(k) is the adhesion coefficient variance corresponding to the wheel; n is the number of scene adhesion coefficients; E(X) is MueInst(k), which is the adhesion coefficient of the wheel (expected value); x is the scene adhesion coefficient; P is the probability corresponding to each scene adhesion coefficient.

[0158] A vehicle can determine the vehicle's scenario adhesion coefficient variance based on the scenario adhesion coefficient variances corresponding to multiple wheels. Specifically, for any wheel, a variance correction coefficient is determined based on first wheel information and second wheel information for the wheel; the second wheel information includes tire torque, acceleration fluctuation value, longitudinal vehicle speed quality factor, Euler angle, longitudinal vehicle speed, and / or load. The vehicle can correct the adhesion coefficient variance corresponding to the wheel based on the variance correction coefficient to obtain a corrected variance. The vehicle can accumulate the reciprocals of the corrected variances for the multiple wheels to obtain a first accumulated value. The vehicle can determine the reciprocal of the first accumulated value as the vehicle's scenario adhesion coefficient variance.

[0159] For example, the vehicle may use the following formula to determine the scene adhesion coefficient variance of the vehicle: MueVarCmn=offset1+offset2+offset3+offset4+offset5 MueVarInst(k)=MueVarInst(k)*Factor1*Factor2*Factor3*MueVarCmn

[0160] Among them, MueVarInst(k) is the adhesion coefficient variance corresponding to the wheel; k takes values ​​of 1, 2, 3, and 4, representing the left front wheel, right front wheel, left rear wheel, and right rear wheel respectively; InstLongRfeMueVar is the scene adhesion coefficient variance of the vehicle; Factor1 is the correction coefficient determined by the vehicle based on the slip rate lookup table; Factor2 is the correction coefficient determined by the vehicle based on the load lookup table; Factor3 is the correction coefficient determined by the vehicle based on the normalized longitudinal force lookup table; offset1 is the correction coefficient determined by the vehicle based on the tire torque lookup table; offset2 is the correction coefficient determined by the vehicle based on the acceleration fluctuation value lookup table; offset3 is the correction coefficient determined by the vehicle based on the longitudinal speed mass factor lookup table; offset4 is the correction coefficient determined by the vehicle based on the Euler angle lookup table; offset5 is the correction coefficient determined by the vehicle based on the longitudinal speed.

[0161] The vehicle compares the first confidence level and the second confidence level when determining that the scene adhesion coefficient variance of the vehicle is less than a variance threshold.

[0162] If the first confidence level is greater than or equal to the second confidence level, the vehicle may determine the first longitudinal adhesion coefficient as the longitudinal adhesion coefficient. In addition, the vehicle may also determine the first confidence level as the confidence level of the longitudinal adhesion coefficient.

[0163] If the first confidence level is less than the second confidence level, the vehicle may determine the second longitudinal adhesion coefficient as the longitudinal adhesion coefficient. In addition, the vehicle may also determine the second confidence level as the confidence level of the longitudinal adhesion coefficient.

[0164] The vehicle may determine the preset longitudinal adhesion coefficient as the longitudinal adhesion coefficient when the variance of the vehicle's scenario adhesion coefficient is greater than or equal to a variance threshold. Additionally, the vehicle may determine a preset confidence level as the confidence level of the longitudinal adhesion coefficient. For example, the preset longitudinal adhesion coefficient may be 1, and the preset confidence level may be 0.

[0165] The beneficial effects of this embodiment are as follows: The vehicle can determine the longitudinal adhesion coefficient of each wheel based on first wheel information for each wheel and multiple scenario adhesion coefficients; the first wheel information includes longitudinal stiffness, slip rate, and normalized longitudinal force. The vehicle can determine the first longitudinal adhesion coefficient and first confidence level of the vehicle in a low-adhesion state, and the second longitudinal adhesion coefficient and second confidence level of the vehicle in a high-adhesion state based on the longitudinal adhesion coefficients of the multiple wheels. The vehicle can determine the longitudinal adhesion coefficient of the vehicle based on the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level. Through the above-described method, the longitudinal adhesion coefficient can be accurately determined, improving the accuracy of determining the vehicle's longitudinal adhesion coefficient, thereby improving the vehicle's controllability under driving conditions and enhancing the safety of passengers.

[0166] The following describes in detail the process of determining the first longitudinal adhesion coefficient and the first confidence level of the vehicle in a low adhesion state through a second method embodiment.

[0167] FIG3a is a flow chart of a second embodiment of a method for determining a longitudinal adhesion coefficient provided in an embodiment of the present application. Referring to FIG3a, the method specifically includes the following steps:

[0168] S301: Obtain activation duration of the stability control system and longitudinal acceleration change rate.

[0169] In this embodiment, the vehicle can obtain the activation duration of the stability control system and the longitudinal acceleration change rate.

[0170] S302: Obtain the slip ratio deviation of each wheel.

[0171] In this embodiment, the vehicle can obtain the slip ratio deviation of each wheel.

[0172] S303: For any wheel, if multiple low-adhesion estimation conditions are met respectively, determine whether the wheel satisfies the first condition or the second condition based on the slip ratio deviation of the wheel and the normalized longitudinal force of the wheel.

[0173] In this embodiment, for any wheel, when the vehicle determines that the wheel meets multiple low-adhesion estimation conditions, it determines whether the wheel meets the first condition or the second condition based on the slip rate deviation of the wheel and the normalized longitudinal force of the wheel.

[0174] Among them, multiple low-attachment estimation conditions include:

[0175] The longitudinal adhesion coefficient of the wheel is greater than a first threshold;

[0176] The estimated flag of the wheel is a valid flag; the activation time is greater than the second threshold;

[0177] The longitudinal acceleration change rate is less than a third threshold.

[0178] The following describes a process in which the vehicle determines whether a wheel satisfies the first condition or the second condition based on the slip ratio deviation and the normalized longitudinal force of the wheel.

[0179] Figure 3b is a schematic diagram of a process for analyzing a wheel according to an embodiment of the present application. As shown in Figure 3b, for any wheel, the vehicle can determine whether the wheel meets multiple low-adhesion estimation conditions.

[0180] If not, the preset longitudinal adhesion coefficient is determined as the first longitudinal adhesion coefficient of the wheel, and the preset confidence is determined as the first confidence of the wheel.

[0181] If so, a determination is made as to whether the wheel's slip ratio deviation is greater than a first deviation threshold and less than or equal to a second deviation threshold, and whether the wheel's normalized longitudinal force is greater than the first longitudinal force threshold. If so, the wheel is determined to satisfy the first condition. If not, a determination is made as to whether the wheel's slip ratio deviation is greater than the second deviation threshold, and whether the wheel's normalized longitudinal force is greater than the first longitudinal force threshold. If so, the wheel is determined to satisfy the second condition. If not, the preset longitudinal adhesion coefficient is determined as the wheel's first longitudinal adhesion coefficient, and the preset confidence level is determined as the wheel's first confidence level.

[0182] For example, the first deviation threshold may be any value between 0 and 0.04, the second deviation threshold may be any value between 0.04 and 1, and the first longitudinal force threshold may be any value between 0 and 0.12.

[0183] S304: Determine a first longitudinal adhesion coefficient and a first confidence level based on the number of wheels that meet the first condition, the number of wheels that meet the second condition, the longitudinal adhesion coefficient and confidence level of each wheel that meets the first condition, and the longitudinal adhesion coefficient and confidence level of each wheel that meets the second condition.

[0184] In this embodiment, the vehicle can determine the first longitudinal adhesion coefficient and the first confidence level based on the number of wheels that meet the first condition, the number of wheels that meet the second condition, the longitudinal adhesion coefficient and confidence level of each wheel that meets the first condition, and the longitudinal adhesion coefficient and confidence level of each wheel that meets the second condition.

[0185] The following describes in detail the process of determining the first longitudinal adhesion coefficient and the first confidence level of the vehicle.

[0186] The vehicle may determine the first longitudinal adhesion coefficient under the first condition as the ratio of the sum of the longitudinal force adhesion coefficients of at least one wheel that meets the first condition to the number of wheels that meet the first condition. Additionally, the vehicle may also determine the first calibration parameter as the first confidence level under the first condition.

[0187] For example, the vehicle may use the following formula to determine the first longitudinal adhesion coefficient and the first confidence level under the first condition: mueFastTrackConfd=cnfdLvlMidWheels

[0188] Among them, nofMidWheels is the number of wheels that meet the first condition, mueFastTrack is the first longitudinal adhesion coefficient under the first condition, mueFastTrackConfd is the first confidence level under the first condition, and cnfdLvlMidWheels is the first calibration parameter.

[0189] The vehicle may determine the ratio of the sum of the longitudinal force adhesion coefficients of at least one wheel that meets the second condition to the number of wheels that meet the second condition as the first longitudinal adhesion coefficient under the second condition. Additionally, the vehicle may also determine the second calibration parameter as the first confidence level under the second condition.

[0190] For example, the vehicle may use the following formula to determine the first longitudinal adhesion coefficient under the second condition and the first confidence level under the second condition: mueFastTrackConfd=cnfdLvlLargeWheels

[0191] Among them, nofLargeWheels is the number of wheels that meet the second condition, mueFastTrack is the first longitudinal adhesion coefficient under the first condition, mueFastTrackConfd is the first confidence level under the second condition, and cnfdLvlLargeWheels is the second calibration parameter.

[0192] The vehicle can analyze the number of wheels that meet the first condition and the number of wheels that meet the second condition:

[0193] The vehicle may determine the first longitudinal adhesion coefficient under the second condition as the first longitudinal adhesion coefficient and the first confidence level under the second condition as the first confidence level when it is determined that the number of wheels satisfying the second condition is greater than 0 and the number of wheels satisfying the first condition is 0.

[0194] The vehicle may determine the first longitudinal adhesion coefficient under the first condition as the first longitudinal adhesion coefficient and the first confidence level under the first condition as the first confidence level when it is determined that the number of wheels satisfying the first condition is greater than 0 and the number of wheels satisfying the second condition is 0.

[0195] When the vehicle determines that the number of wheels meeting the first condition is greater than 0 and the number of wheels meeting the second condition is greater than 0, it may determine the maximum of the first longitudinal adhesion coefficient under the first condition and the first longitudinal adhesion coefficient under the second condition as the first longitudinal adhesion coefficient, and determine the confidence level corresponding to the maximum value as the first confidence level. In one implementation, after determining the confidence level corresponding to the maximum value as the first confidence level, the vehicle may further adjust the first confidence level. For example, the vehicle may add the first confidence level to a third calibration parameter to adjust the first confidence level.

[0196] When the number of wheels that meet the first condition is determined to be 0 and the number of wheels that meet the second condition is determined to be 0, the vehicle may determine the preset longitudinal adhesion coefficient as the first longitudinal adhesion coefficient and the preset confidence level as the first confidence level. For example, the preset longitudinal adhesion coefficient may be 1 and the preset confidence level may be 0.

[0197] The beneficial effects of this embodiment are as follows: For any wheel, when the vehicle determines that the wheel meets multiple low-adhesion estimation conditions, the vehicle determines whether the wheel meets the first condition or the second condition based on the wheel's slip rate deviation and the wheel's normalized longitudinal force. The vehicle can determine a first longitudinal adhesion coefficient and a first confidence level based on the number of wheels meeting the first condition, the number of wheels meeting the second condition, the longitudinal adhesion coefficient and confidence level of each wheel meeting the first condition, and the longitudinal adhesion coefficient and confidence level of each wheel meeting the second condition. Through this approach, the vehicle can accurately determine the first longitudinal adhesion coefficient and the first confidence level in a low-adhesion state. This allows the vehicle to accurately determine the longitudinal adhesion coefficient and the confidence level based on the first longitudinal adhesion coefficient and the first confidence level, improving the matching of the longitudinal adhesion coefficient with the actual vehicle conditions and thereby enhancing the vehicle's controllability.

[0198] The following describes in detail the implementation process of determining the second longitudinal adhesion coefficient and the second confidence level of the vehicle in a high adhesion state through a third method embodiment.

[0199] FIG4a is a flow chart of a third embodiment of a method for determining a longitudinal adhesion coefficient provided in an embodiment of the present application. Referring to FIG4a , the method specifically includes the following steps:

[0200] S401: Obtain activation duration of the stability control system.

[0201] In this embodiment, the vehicle may obtain the activation duration of the stability control system.

[0202] S402: For any wheel, if multiple high-adhesion estimation conditions are met respectively, determine whether the wheel satisfies the third condition or the fourth condition based on the normalized longitudinal force of the wheel.

[0203] In this embodiment, for any wheel, when the vehicle determines that the wheel meets multiple high-adhesion estimation conditions, it determines whether the wheel meets the third condition or the fourth condition based on the normalized longitudinal force of the wheel.

[0204] Among them, multiple high-attachment estimation conditions include:

[0205] The longitudinal adhesion coefficient of the wheel is greater than a fourth threshold value; it should be noted that the fourth threshold value may be any value between 0.4 and 1;

[0206] The estimated mark position of the wheel is the effective mark position;

[0207] The activation duration is greater than the fifth threshold; it should be noted that the fifth threshold can be any value between 300 milliseconds and 500 milliseconds.

[0208] The following describes a process in which the vehicle determines whether a wheel satisfies the third condition or the fourth condition based on the normalized longitudinal force of the wheel.

[0209] Figure 4b is a schematic diagram of another process for analyzing wheels according to an embodiment of the present application. As shown in Figure 4b, for any wheel, the vehicle can determine whether the wheel meets multiple high-adhesion estimation conditions.

[0210] If not, the preset longitudinal adhesion coefficient is determined as the second longitudinal adhesion coefficient of the wheel, and the preset confidence is determined as the second confidence of the wheel.

[0211] If so, a determination is made as to whether the normalized longitudinal force of the wheel is greater than the second longitudinal force threshold and less than or equal to the third longitudinal force threshold. If so, the wheel is determined to satisfy the third condition. If not, a determination is made as to whether the normalized longitudinal force of the wheel is greater than the third longitudinal force threshold. If so, the wheel is determined to satisfy the fourth condition. If not, the preset longitudinal adhesion coefficient is determined as the second longitudinal adhesion coefficient of the wheel, and the preset confidence level is determined as the second confidence level of the wheel.

[0212] For example, the second longitudinal force threshold value may be any value between 0 and 0.55, and the third longitudinal force threshold value may be any value between 0.65 and 1.

[0213] S403: Determine a second longitudinal adhesion coefficient and a second confidence level based on the number of wheels that meet the third condition, the number of wheels that meet the fourth condition, the longitudinal adhesion coefficient and confidence level of each wheel that meets the third condition, and the longitudinal adhesion coefficient and confidence level of each wheel that meets the fourth condition.

[0214] In this embodiment, the vehicle can determine the second longitudinal adhesion coefficient and the second confidence level based on the number of wheels that meet the third condition, the number of wheels that meet the fourth condition, the longitudinal adhesion coefficient and confidence level of each wheel that meets the third condition, and the longitudinal adhesion coefficient and confidence level of each wheel that meets the fourth condition.

[0215] The process of determining the second longitudinal adhesion coefficient and the second confidence level of the vehicle is described in detail below.

[0216] The vehicle may determine the ratio of the sum of the longitudinal force adhesion coefficients of at least one wheel that meets the third condition to the number of wheels that meet the third condition as the second longitudinal adhesion coefficient under the third condition. Additionally, the vehicle may also determine a fourth calibration parameter as the second confidence level under the third condition.

[0217] For example, the vehicle may use the following formula to determine the second longitudinal adhesion coefficient under the third condition and the second confidence level under the third condition: mueFastTrackConfd=cnfdLvlMidWheels

[0218] Among them, nofMidWheels is the number of wheels that meet the third condition, mueFastTrack is the second longitudinal adhesion coefficient under the third condition, mueFastTrackConfd is the second confidence level under the third condition, and cnfdLvlMidWheels is the fourth calibration parameter.

[0219] The vehicle may determine the ratio of the sum of the longitudinal force adhesion coefficients of at least one wheel that meets the fourth condition to the number of wheels that meet the fourth condition as the second longitudinal adhesion coefficient under the fourth condition. Additionally, the vehicle may also determine the fifth calibration parameter as the second confidence level under the fourth condition.

[0220] For example, the vehicle may use the following formula to determine the second longitudinal adhesion coefficient under the fourth condition and the second confidence level under the fourth condition: mueFastTrackConfd=cnfdLvlLargeWheels

[0221] Among them, nofLargeWheels is the number of wheels that meet the fourth condition, mueFastTrack is the second longitudinal adhesion coefficient under the fourth condition, mueFastTrackConfd is the second confidence level under the fourth condition, and cnfdLvlLargeWheels is the fifth calibration parameter.

[0222] The vehicle can analyze the number of wheels that meet the third condition and the number of wheels that meet the fourth condition:

[0223] The vehicle may determine the second longitudinal adhesion coefficient under the fourth condition as the second longitudinal adhesion coefficient and the second confidence level under the fourth condition as the second confidence level when it is determined that the number of wheels satisfying the fourth condition is greater than 0 and the number of wheels satisfying the third condition is 0.

[0224] The vehicle may determine the second longitudinal adhesion coefficient under the third condition as the second longitudinal adhesion coefficient and the second confidence level under the third condition as the second confidence level when it is determined that the number of wheels satisfying the third condition is greater than 0 and the number of wheels satisfying the fourth condition is 0.

[0225] If the vehicle determines that the number of wheels meeting the third condition is greater than 0 and the number of wheels meeting the fourth condition is greater than 0, it may determine the maximum of the second longitudinal adhesion coefficient under the third condition and the second longitudinal adhesion coefficient under the fourth condition as the second longitudinal adhesion coefficient, and determine the confidence level corresponding to the maximum value as the second confidence level. In one implementation, after determining the confidence level corresponding to the maximum value as the second confidence level, the vehicle may further adjust the second confidence level. For example, the vehicle may add the second confidence level to the sixth calibration parameter to adjust the second confidence level.

[0226] When the number of wheels meeting the third condition is determined to be 0 and the number of wheels meeting the fourth condition is determined to be 0, the vehicle may determine the preset longitudinal adhesion coefficient as the second longitudinal adhesion coefficient and the preset confidence level as the second confidence level. For example, the preset longitudinal adhesion coefficient may be 1 and the preset confidence level may be 0.

[0227] The beneficial effects of this embodiment are as follows: For any wheel, if the vehicle determines that the wheel meets multiple high-adhesion estimation conditions, it can determine whether the wheel meets the third condition or the fourth condition based on the normalized longitudinal force of the wheel. The vehicle can determine the second longitudinal adhesion coefficient and the second confidence level based on the number of wheels meeting the third condition, the number of wheels meeting the fourth condition, the longitudinal adhesion coefficient and confidence level of each wheel meeting the third condition, and the longitudinal adhesion coefficient and confidence level of each wheel meeting the fourth condition. In this manner, the vehicle can accurately determine the second longitudinal adhesion coefficient and the second confidence level in a high-adhesion state, thereby enabling the vehicle to accurately determine the longitudinal adhesion coefficient and the confidence level based on the second longitudinal adhesion coefficient and the second confidence level, improving the matching of the longitudinal adhesion coefficient with the actual vehicle conditions and thereby enhancing the vehicle's controllability.

[0228] FIG5 is a schematic diagram of the structure of the device for determining the longitudinal adhesion coefficient provided in an embodiment of the present application. As shown in FIG5 , the device 50 for determining the longitudinal adhesion coefficient includes a processing module 51 and a fusion module 52.

[0229] a processing module 51 for determining a longitudinal adhesion coefficient of each wheel based on first wheel information of each wheel and a plurality of scenario adhesion coefficients, wherein the first wheel information includes longitudinal stiffness, slip ratio, and normalized longitudinal force;

[0230] The processing module 51 is further configured to determine, based on the longitudinal adhesion coefficients of the plurality of wheels, a first longitudinal adhesion coefficient and a first confidence level of the vehicle in a low adhesion state, and a second longitudinal adhesion coefficient and a second confidence level of the vehicle in a high adhesion state;

[0231] The fusion module 52 is configured to determine the longitudinal adhesion coefficient of the vehicle according to the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level.

[0232] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0233] In one implementation, the processing module 51 is specifically configured to:

[0234] For any wheel, determine the probability corresponding to each scene adhesion coefficient based on the first wheel information of the wheel and multiple scene adhesion coefficients;

[0235] The longitudinal adhesion coefficient of the wheel is determined according to the probability corresponding to each scene adhesion coefficient and the multiple scene adhesion coefficients.

[0236] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0237] In one implementation, the processing module 51 is specifically configured to:

[0238] Obtain the activation duration of the stability control system and the rate of change of longitudinal acceleration;

[0239] Get the slip ratio deviation of each wheel;

[0240] For any wheel, if multiple low-adhesion estimation conditions are met, determining whether the wheel satisfies a first condition or a second condition based on the wheel slip ratio deviation and the normalized longitudinal force of the wheel;

[0241] Determining a first longitudinal adhesion coefficient and a first confidence level based on the number of wheels that meet the first condition, the number of wheels that meet the second condition, the longitudinal adhesion coefficient and the confidence level of each wheel that meets the first condition, and the longitudinal adhesion coefficient and the confidence level of each wheel that meets the second condition;

[0242] Among them, multiple low-attachment estimation conditions include:

[0243] The longitudinal adhesion coefficient of the wheel is greater than the first threshold, the estimated flag of the wheel is a valid flag, the activation time is greater than the second threshold, and the longitudinal acceleration change rate is less than the third threshold.

[0244] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0245] In one implementation, the processing module 51 is specifically configured to:

[0246] If the slip ratio deviation of the wheel is greater than the first deviation threshold and less than or equal to the second deviation threshold, and the normalized longitudinal force of the wheel is greater than the first longitudinal force threshold, then determining that the wheel satisfies the first condition;

[0247] If the slip ratio deviation of the wheel is greater than the second deviation threshold, and the normalized longitudinal force of the wheel is greater than the first longitudinal force threshold, the wheel is determined to be a wheel that meets the second condition.

[0248] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0249] In one implementation, the processing module 51 is specifically configured to:

[0250] Get the activation time of the stability control system;

[0251] For any wheel, if multiple high-adhesion estimation conditions are met, determining whether the wheel satisfies the third condition or the fourth condition based on the normalized longitudinal force of the wheel;

[0252] determining a second longitudinal adhesion coefficient and a second confidence level based on the number of wheels that meet the third condition, the number of wheels that meet the fourth condition, the longitudinal adhesion coefficient and the confidence level of each wheel that meets the third condition, and the longitudinal adhesion coefficient and the confidence level of each wheel that meets the fourth condition;

[0253] Among them, multiple high-attachment estimation conditions include:

[0254] The longitudinal adhesion coefficient of the wheel is greater than the fourth threshold, the estimated flag position of the wheel is a valid flag position, and the activation time is greater than the fifth threshold.

[0255] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0256] In one implementation, the processing module 51 is specifically configured to:

[0257] If the normalized longitudinal force of the wheel is greater than the second longitudinal force threshold and less than or equal to the third longitudinal force threshold, determining that the wheel is a wheel that meets the third condition;

[0258] If the normalized longitudinal force of the wheel is greater than the third longitudinal force threshold, the wheel is determined to be a wheel that meets the fourth condition.

[0259] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0260] In one implementation, the fusion module 52 is specifically configured to:

[0261] Determine the adhesion coefficient variance corresponding to each wheel based on the longitudinal adhesion coefficient of the wheel, the probability corresponding to each scene adhesion coefficient, and the adhesion coefficients of multiple scenes;

[0262] Determining a scene adhesion coefficient variance of the vehicle according to scene adhesion coefficient variances corresponding to a plurality of wheels;

[0263] When the scene adhesion coefficient variance of the vehicle is less than the variance threshold, if the first confidence level is greater than or equal to the second confidence level, determining the first longitudinal adhesion coefficient as the longitudinal adhesion coefficient;

[0264] If the first confidence level is less than the second confidence level, determining the second longitudinal adhesion coefficient as the longitudinal adhesion coefficient;

[0265] When the scene adhesion coefficient variance of the vehicle is greater than or equal to the variance threshold, the preset longitudinal adhesion coefficient is determined as the longitudinal adhesion coefficient.

[0266] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0267] In one implementation, the fusion module 52 is specifically configured to:

[0268] For any wheel, determining a variance correction coefficient based on first wheel information and second wheel information of the wheel; the second wheel information includes: tire torque, acceleration fluctuation value, longitudinal vehicle speed quality factor, Euler angle, longitudinal vehicle speed, and / or load;

[0269] According to the variance correction coefficient, the adhesion coefficient variance corresponding to the wheel is corrected to obtain the corrected variance;

[0270] Accumulating the reciprocals of the correction variances of the multiple wheels to obtain a first accumulated value;

[0271] The reciprocal of the first accumulated value is determined as the scene adhesion coefficient variance of the vehicle.

[0272] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0273] In one implementation, the processing module 51 is specifically configured to:

[0274] determining a longitudinal adhesion coefficient of each wheel based on first wheel information of each wheel and a plurality of scenario adhesion coefficients when the vehicle satisfies any one or more longitudinal estimation conditions of the plurality of longitudinal estimation conditions;

[0275] Among them, multiple longitudinal estimation conditions include:

[0276] The vehicle's speed is within a preset range;

[0277] The vehicle's acceleration is less than or equal to the acceleration threshold;

[0278] The vehicle's angular velocity is less than or equal to the angular velocity threshold;

[0279] The duration for which the vehicle's steering wheel angle is greater than the angle threshold is less than or equal to a preset duration;

[0280] The signal state of the vehicle's sensor signal is normal;

[0281] The vehicle's stability control system is activated.

[0282] The device for determining the longitudinal adhesion coefficient provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0283] Figure 6 is a structural diagram of a vehicle provided in an embodiment of the present application. As shown in Figure 6 , vehicle 60 includes a processor 61 and a memory 62. Processor 61 is communicatively coupled to memory 62, which is configured to store computer-executable instructions. Processor 61 is configured to execute the computer-executable instructions stored in memory 62 to implement the technical solutions of any of the aforementioned method embodiments.

[0284] Optionally, the memory 62 may be independent or integrated with the processor 61. Optionally, when the memory 62 is a device independent of the processor 61, the vehicle 60 may further include a bus 63 configured to connect the above devices.

[0285] The vehicle is configured to execute the technical solution in any of the aforementioned method embodiments, and its implementation principles and technical effects are similar and will not be described in detail here.

[0286] An embodiment of the present application further provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are configured to implement the technical solution provided by any of the aforementioned method embodiments.

[0287] An embodiment of the present application also provides a computer program product, including a computer program, which is configured to implement the technical solution provided by the aforementioned method embodiment when executed by a processor.

[0288] Those skilled in the art will appreciate that all or part of the steps in the above method can be completed by instructing relevant hardware (such as a processor) through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a disk or an optical disk. Optionally, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits. Accordingly, each module / unit in the above embodiment can be implemented in the form of hardware, for example, by implementing its corresponding function through an integrated circuit, or in the form of a software functional module, for example, by executing a program / instruction stored in a memory by a processor to implement its corresponding function. This application is not limited to any particular form of combination of hardware and software.

[0289] Finally, it should be noted that each of the above embodiments is only used to illustrate the technical solution of the present application, rather than to limit it. Although the present application has been described in detail with reference to each of the above embodiments, a person skilled in the art should understand that the technical solution described in each of the above embodiments can still be modified, or some or all of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution of each embodiment of the present application.

Claims

1. A method for determining a longitudinal adhesion coefficient, comprising: determining a longitudinal adhesion coefficient of each wheel based on first wheel information of each wheel and a plurality of scenario adhesion coefficients, wherein the first wheel information includes longitudinal stiffness, slip ratio, and normalized longitudinal force; determining, based on the longitudinal adhesion coefficients of the plurality of wheels, a first longitudinal adhesion coefficient and a first confidence level of the vehicle in a low adhesion state, and a second longitudinal adhesion coefficient and a second confidence level of the vehicle in a high adhesion state; A longitudinal adhesion coefficient of the vehicle is determined based on the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level.

2. The method of claim 1, wherein: For any wheel, determining a probability corresponding to each scene adhesion coefficient according to the first wheel information of the wheel and the multiple scene adhesion coefficients; The longitudinal adhesion coefficient of the wheel is determined according to the probability corresponding to each scene adhesion coefficient and the multiple scene adhesion coefficients.

3. The method of claim 2, wherein: Obtain the activation duration of the stability control system and the rate of change of longitudinal acceleration; Get the slip ratio deviation of each wheel; For any wheel, if multiple low-adhesion estimation conditions are met, determining whether the wheel satisfies a first condition or a second condition based on the slip ratio deviation of the wheel and the normalized longitudinal force of the wheel; determining the first longitudinal adhesion coefficient and the first confidence level based on the number of wheels that meet the first condition, the number of wheels that meet the second condition, the longitudinal adhesion coefficient and the confidence level of each wheel that meets the first condition, and the longitudinal adhesion coefficient and the confidence level of each wheel that meets the second condition; The multiple low attachment estimation conditions include: The longitudinal adhesion coefficient of the wheel is greater than a first threshold, the estimated flag of the wheel is a valid flag, the activation duration is greater than a second threshold, and the longitudinal acceleration change rate is less than a third threshold.

4. The method of claim 3, wherein: If the slip ratio deviation of the wheel is greater than a first deviation threshold and less than or equal to a second deviation threshold, and the normalized longitudinal force of the wheel is greater than a first longitudinal force threshold, determining that the wheel is the wheel that meets the first condition; If the slip ratio deviation of the wheel is greater than the second deviation threshold, and the normalized longitudinal force of the wheel is greater than the first longitudinal force threshold, the wheel is determined to be the wheel that meets the second condition.

5. The method of claim 2, wherein: Get the activation time of the stability control system; For any wheel, if multiple high-adhesion estimation conditions are met respectively, determining whether the wheel satisfies a third condition or a fourth condition based on the normalized longitudinal force of the wheel; determining the second longitudinal adhesion coefficient and the second confidence level based on the number of wheels that meet the third condition, the number of wheels that meet the fourth condition, the longitudinal adhesion coefficient and the confidence level of each wheel that meets the third condition, and the longitudinal adhesion coefficient and the confidence level of each wheel that meets the fourth condition; The multiple high-attachment estimation conditions include: The longitudinal adhesion coefficient of the wheel is greater than a fourth threshold, the estimated flag position of the wheel is a valid flag position, and the activation duration is greater than a fifth threshold.

6. The method of claim 5, wherein: If the normalized longitudinal force of the wheel is greater than a second longitudinal force threshold and less than or equal to a third longitudinal force threshold, determining that the wheel is the wheel that meets the third condition; If the normalized longitudinal force of the wheel is greater than the third longitudinal force threshold, the wheel is determined to be the wheel that meets the fourth condition.

7. The method of claim 1, wherein: determining an adhesion coefficient variance corresponding to each wheel according to the longitudinal adhesion coefficient of the wheel, the probability corresponding to each scene adhesion coefficient, and the multiple scene adhesion coefficients; Determining a scene adhesion coefficient variance of the vehicle according to scene adhesion coefficient variances corresponding to a plurality of wheels; When a scene adhesion coefficient variance of the vehicle is less than a variance threshold, and if the first confidence level is greater than or equal to the second confidence level, determining the first longitudinal adhesion coefficient as the longitudinal adhesion coefficient; If the first confidence level is less than the second confidence level, determining the second longitudinal adhesion coefficient as the longitudinal adhesion coefficient; When the scene adhesion coefficient variance of the vehicle is greater than or equal to the variance threshold, a preset longitudinal adhesion coefficient is determined as the longitudinal adhesion coefficient.

8. The method of claim 7, wherein: For any wheel, determining a variance correction coefficient according to the first wheel information and the second wheel information of the wheel; The second wheel information includes: tire torque, acceleration fluctuation value, longitudinal vehicle speed quality factor, Euler angle, longitudinal vehicle speed, and / or load; Correcting the adhesion coefficient variance corresponding to the wheel according to the variance correction coefficient to obtain a corrected variance; Accumulating the reciprocals of the correction variances of the multiple wheels to obtain a first accumulated value; The reciprocal of the first accumulated value is determined as the scene adhesion coefficient variance of the vehicle.

9. The method of claim 1, wherein: determining a longitudinal adhesion coefficient of each wheel according to first wheel information of each wheel and a plurality of scenario adhesion coefficients when the vehicle satisfies any one or more longitudinal estimation conditions of the plurality of longitudinal estimation conditions; The plurality of longitudinal estimation conditions include: The speed of the vehicle is within a preset range; The acceleration of the vehicle is less than or equal to an acceleration threshold; The angular velocity of the vehicle is less than or equal to an angular velocity threshold; The duration for which the steering wheel angle of the vehicle is greater than the angle threshold is less than or equal to a preset duration; The signal state of the sensor signal of the vehicle is normal; The vehicle activates a stability control system.

10. A device for determining a longitudinal adhesion coefficient, comprising: a processing module configured to determine a longitudinal adhesion coefficient of each wheel based on first wheel information of each wheel and a plurality of scenario adhesion coefficients, wherein the first wheel information includes longitudinal stiffness, slip ratio, and normalized longitudinal force; The processing module is further configured to determine, based on the longitudinal adhesion coefficients of the plurality of wheels, a first longitudinal adhesion coefficient and a first confidence level of the vehicle in a low adhesion state, and a second longitudinal adhesion coefficient and a second confidence level of the vehicle in a high adhesion state; A fusion module is configured to determine a longitudinal adhesion coefficient of the vehicle based on the first longitudinal adhesion coefficient, the first confidence level, the second longitudinal adhesion coefficient, and the second confidence level.

11. A vehicle comprising: a processor, and a memory communicatively connected to the processor; The memory is configured to store computer-executable instructions; The processor is configured to execute the computer-executable instructions stored in the memory to implement the method for determining the longitudinal adhesion coefficient according to any one of claims 1 to 9.

12. A computer-readable storage medium, wherein computer-executable instructions are stored in the computer-readable storage medium, wherein when the computer-executable instructions are executed by a processor, the method for determining the longitudinal adhesion coefficient according to any one of claims 1 to 9 is implemented.

13. A computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the method for determining the longitudinal adhesion coefficient according to any one of claims 1 to 9 is implemented.

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