Vehicle control method and device, electronic equipment and storage medium
Patent Information
- Application Number
- CN202411453157.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-01-28
AI Technical Summary
The lack of effective utilization of magic formula models in the prior art has led to poor performance in vehicle dynamic control, especially the failure to accurately estimate the adhesion coefficient under high slip rate.
By using the target coefficient to correct the initial magic formula, the target magic formula is obtained, the decoupled curvature factors and rigid factor, and the data point is determined based on the operating parameters of the vehicle. control.
Improve the safety and stability of the vehicle under complex road conditions, simplify the operation process, reduce the dependence on professional and technical personnel, and reduce time and economic costs.
Smart Images
Figure CN119370100A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of vehicle control, and in particular to a vehicle control method and device, electronic equipment and storage medium. Background Art
[0002] Despite the continuous development of chassis-by-wire technology, the current dynamic motion control of the whole vehicle still mainly relies on traditional complex models such as Adams and CarSim to repeatedly calibrate on various road surfaces (such as dry asphalt, dry cement, wet asphalt, wet cobblestone, snow and ice) to obtain the vehicle tire model. However, this method fails to fully utilize the 4-wheel distributed control technology of the chassis-by-wire, only simply classifies the road surface, and fails to accurately estimate the adhesion coefficient under high slip rate, thus limiting the development potential of intelligent independent chassis-by-wire. Currently, there is little research on real-time fitting of adhesion curves, and there is also insufficient research on the improvement and optimization of magic formulas. Most studies still rely on old models such as Delft Tire96, Delft Tire97, PAC2002, etc., and lack effective use of the MF (Magic Formula) model, that is, the existing calibration work is complex and time-consuming, resulting in poor vehicle dynamic control performance on non-standard roads.
[0003] There is no effective solution to the above problems in the related technology. Summary of the invention
[0004] The present application provides a vehicle control method and device, an electronic device and a storage medium to solve the problem in the prior art of lacking an effective magic formula model, resulting in poor performance in vehicle dynamic control.
[0005] In a first aspect, the present application provides a vehicle control method, comprising: using a target coefficient to correct an initial magic formula of a tire to obtain a target magic formula, wherein the target coefficient is multiplied by a target result in the initial magic formula, and the target result is an arc tangent result of multiplying a slip rate by a stiffness factor; the target coefficient is used to decouple a curvature factor and a stiffness factor in the target magic formula; obtaining operating parameters at different times during an acceleration process after the vehicle starts, and determining corresponding data points based on the operating parameters, wherein the data points include a slip rate and a first adhesion coefficient; determining a second adhesion coefficient of a current road surface according to the data points at different times and the target magic formula, and controlling the vehicle based on the second adhesion coefficient.
[0006] Optionally, obtaining operating parameters at different times during the acceleration process after the vehicle starts, and determining corresponding data points based on the operating parameters includes: obtaining operating parameters of the vehicle tires, wherein the operating parameters include: output torque, wheel speed, vehicle speed and vertical force; determining the ratio of the output torque to the tire radius as the longitudinal force of the tire, and determining the ratio of the longitudinal force to the vertical force as the first adhesion coefficient; determining the difference between the wheel speed and the vehicle speed, and determining the ratio of the difference to the vehicle speed as the slip rate; determining the first adhesion coefficient and the slip rate as a set of the data points.
[0007] Optionally, determining a second adhesion coefficient of the current road surface according to data points at different times and the target magic formula, and controlling the vehicle based on the second adhesion coefficient includes: determining values of each coefficient in the target magic formula according to data points at different times; determining the second adhesion coefficient based on the target magic formula for determining the coefficient values and data points at different times, and controlling the vehicle based on the second adhesion coefficient.
[0008] Optionally, the values of each coefficient in the target magic formula are determined according to data points at different times, including: setting an error function, wherein the error function represents the sum of squares of differences between predicted values and actual values obtained by substituting all data points into the magic formula; repeatedly iterating the values of each coefficient in the target magic formula through a numerical optimization method until the value of the error function is minimized; and determining the values of each coefficient in the target magic formula corresponding to the minimum value of the error function as the values of each coefficient in the target magic formula for determining the second adhesion coefficient.
[0009] Optionally, the initial magic formula of the tire is modified by using the target coefficient to obtain the target magic formula, which includes: adding the target coefficient G to the following initial magic formula x : F x =D x sin{C x arctan[B x λ-E x (B x λ-arctanB x λ)]}
[0010] Get the target magic formula: F x =D x sin{C x arctan[B x λ-E x (B x λ-G x arctanB x λ)]}
[0011] Among them, Fx represents the longitudinal force, x is the longitudinal slip rate, D x is the peak factor, C x is the shape factor, B x is the stiffness factor, E x is the curvature factor, λ is the slip rate; λ=x+Sh, Sh is the horizontal offset.
[0012] Optionally, determining the second adhesion coefficient based on a target magic formula for determining the coefficient value and data points at different times, and controlling the vehicle based on the second adhesion coefficient includes: determining the longitudinal force at the target moment based on the data points at the target moment and the target magic formula, and determining the second adhesion coefficient based on the ratio of the longitudinal force to the vertical force of the tire; when the difference between the determined second adhesion coefficient and the actually measured adhesion coefficient is less than a preset threshold, controlling the vehicle at the target moment based on the determined second adhesion coefficient.
[0013] Optionally, controlling the vehicle at the target moment based on the determined second adhesion coefficient includes: determining the adhesion of the vehicle tires based on the second adhesion coefficient; obtaining the slip rate of the road surface at the target moment, and allocating corresponding torque to the vehicle tires at the target moment based on the slip rate and the adhesion.
[0014] In a second aspect, the present application provides a vehicle control device, comprising: a first processing module, used to correct the initial magic formula of the tire using a target coefficient to obtain a target magic formula, wherein the target coefficient is multiplied by the target result in the initial magic formula, and the target result is the arc tangent result of the slip rate multiplied by the stiffness factor; the target coefficient is used to decouple the curvature factor and the stiffness factor in the target magic formula; a second processing module, used to obtain operating parameters at different times during the acceleration process after the vehicle starts, and determine corresponding data points based on the operating parameters, wherein the data points include the slip rate and the first adhesion coefficient; a third processing module, determines the second adhesion coefficient of the current road surface according to the data points at different times and the target magic formula, and controls the vehicle based on the second adhesion coefficient.
[0015] In a third aspect, the present application provides an electronic device comprising: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor connected to the at least one bus; and at least one memory connected to the at least one bus, wherein the processor is configured to execute instructions for executing the vehicle control method described in the first aspect of the present application.
[0016] In a fourth aspect, the present application further provides a computer storage medium storing computer executable instructions, wherein the computer executable instructions are used to execute the vehicle control method described in the first aspect of the present application.
[0017] The above technical solution provided by the embodiment of the present application has the following advantages over the prior art: the method provided by the embodiment of the present application uses the target coefficient to correct the initial magic tire formula to obtain the target magic formula, which pays attention to the difference between the front and rear ends of the slip rate, so that the curve accuracy of the target magic tire formula is closer to the road conditions, and does not bring more complex computing power consumption. Therefore, after obtaining the operating parameters at different times during the acceleration process after the vehicle starts, the corresponding data points are determined according to the operating parameters, and the coefficients of the target magic tire formula determined by the data points can then be used to more accurately identify the second adhesion coefficient of the current road surface according to the target magic formula. Therefore, when the second adhesion coefficient determined by the embodiment of the present application controls the vehicle, it can enhance the safety and stability of the vehicle under complex road conditions. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0020] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.
[0021] Figure 1 A flow chart of a vehicle control method provided in an embodiment of the present application;
[0022] Figure 2 Add coefficient G to the magic formula in the embodiment of this application x Schematic diagram of the curve change after
[0023] Figure 3 Add coefficient G to the magic formula in the embodiment of this application x Schematic diagram of the change of rear slip rate;
[0024] Figure 4A schematic diagram of the structure of a vehicle control device provided in an embodiment of the present application;
[0025] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION
[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0027] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.
[0028] First, the relevant terms involved in the embodiments of the present application are explained;
[0029] Wire-controlled chassis: Wire-controlled technology (x-by-wire), a revolutionary innovation originating from the aviation field, was originally applied to the flight control system (fly-by-wire) of aircraft. Its working principle is very intuitive: the pilot's operating actions are captured by sensors, and these actions are then converted into electrical signals, which are precisely processed by the electronic control unit (ECU) and finally transmitted to the actuator to achieve precise control of the aircraft. This technology, also known as electronic control technology, uses precise electronic sensors and actuators to replace traditional mechanical or hydraulic systems. The automotive chassis system that applies this technology is called a wire-controlled chassis. In the scenario of intelligent driving, the vehicle's perception module is responsible for collecting information about the surrounding environment, and the decision-making and planning module makes task decisions based on this information and plans the best driving trajectory for the vehicle. Subsequently, the control module is responsible for ensuring that the vehicle strictly follows this planned trajectory.
[0030] In order to solve the problem that the prior art lacks effective magic formula models, resulting in poor performance of vehicle dynamic control, the present application provides a vehicle control method, such as Figure 1 As shown, the steps of the method include:
[0031] Step 101, using a target coefficient to correct an initial magic formula of the tire to obtain a target magic formula, wherein the target coefficient is multiplied by a target result in the initial magic formula, and the target result is an arc tangent result of multiplying the slip rate by the stiffness factor; the target coefficient is used to decouple the curvature factor and the stiffness factor in the target magic formula;
[0032] It should be noted that, based on the target coefficient, the high slip rate part of the modified target magic formula is more separated than the high slip rate part of the initial magic formula. In addition, the initial magic formula in the embodiment of the present application is mainly used for the research on the front linear area of the auxiliary force curve (slip rate 0% to 15%) and the middle section to obtain the optimal adhesion area (slip rate 15% to 35%), while the high slip rate part of the rear section is not distinguished. In order to make better use of this formula, in the high slip rate part, an additional target coefficient is added for this purpose, so that the characteristics of the changes in the front and rear sections can be slightly separated, so that the target magic formula can be more fitted in the high slip part than the initial magic formula. In the specific example, the target magic formula is as follows:
[0033] F x =D x sin{C x arctan[B x λ-E x (B x λ-G x arctan B x λ)]}
[0034] Among them, G x is the target coefficient, F x represents the longitudinal force, x is the longitudinal slip rate, D x is the peak factor, C x is the shape factor, B x is the stiffness factor, E x is the curvature factor, λ is the slip rate; λ=x+Sh, Sh is the horizontal offset.
[0035] It should be noted that the high slip part of the magic formula refers to the description of the mechanical properties of the tire under high-speed sliding or high slip rate conditions.
[0036] Step 102, obtaining operating parameters at different times during the acceleration process after the vehicle starts, and determining corresponding data points based on the operating parameters, wherein the data points include a slip ratio and a first adhesion coefficient;
[0037] In a specific example, the operating parameters may include the output torque of a single tire, wheel speed, vehicle speed, vertical force, etc. Based on the operating parameters, the slip rate and adhesion coefficient of the current ground surface can be determined.
[0038] Step 103, determining a second adhesion coefficient of the current road surface according to the data points at different times and the target magic formula, and controlling the vehicle based on the second adhesion coefficient.
[0039] Through the above steps 101 to 103, the target magic formula obtained by correcting the initial magic tire formula with the target coefficient pays attention to the difference between the front and rear ends of the slip rate, so that the curve accuracy of the target magic tire formula is closer to the road conditions, and it does not bring more complex computing power consumption. Therefore, after obtaining the operating parameters of the vehicle at different times during the acceleration process after starting, the corresponding data points are determined according to the operating parameters, and the coefficients of the target magic tire formula determined by the data points can then be used to more accurately identify the second adhesion coefficient of the current road surface according to the target magic formula. Therefore, when the second adhesion coefficient determined by the embodiment of the present application controls the vehicle, it can enhance the safety and stability of the vehicle under complex road conditions.
[0040] It can be seen that the initial magic formula in the embodiment of the present application is the following formula:
[0041] F x =D x sin{C x arctan[B x λ-E x (B x λ-arctanB x λ)]}
[0042] Adopt target coefficient G x The initial magic formula is modified to obtain the following target magic formula:
[0043] F x =D x sin{C x arctan[B x λ-E x (B x λ-G x arctanB x λ)]}
[0044] Among them, F x represents the longitudinal force, x is the longitudinal slip rate, D x is the peak factor, C x is the shape factor, B x is the stiffness factor, E x is the curvature factor, λ is the slip rate; λ=x+Sh, Sh is the horizontal offset.
[0045] In this regard, in a specific example, Figure 2 As shown, in different G xThe curve changes under the coefficient. x The coefficient can more accurately fit the actual real-time detected slip rate, such as Figure 3 In this formula, G x Adjusted arctan(B x λ), making the input of the arctan function more complex and dynamic. This structure can adjust the early sensitivity to the input variable and separate it from the later output change. Therefore, in the case of high slip rate, more precise adjustment can be provided in the embodiment of the present application, that is, the target coefficient C in the embodiment of the present application is x This provides greater sensitivity and adaptability, allowing MF models based on the magic formula to more finely tune their corresponding responses.
[0046] In the embodiment of the present application, the operating parameters may include the output torque, wheel speed, vehicle speed and vertical force of a single tire, etc. The first adhesion coefficient and slip rate may be further determined based on the relationship between the various operating parameters. Therefore, the method of obtaining the operating parameters at different times during the acceleration process after the vehicle starts and determining the corresponding data points based on the operating parameters involved in the above step 102 in the embodiment of the present application may further include:
[0047] Step 11, obtaining operating parameters of the vehicle tire, wherein the operating parameters include output torque, wheel speed, vehicle speed and vertical force;
[0048] Step 12, determining the ratio of the output torque to the tire radius as the longitudinal force of the tire, and determining the ratio of the longitudinal force to the vertical force as the first adhesion coefficient;
[0049] Step 13, determining the difference between the wheel speed and the vehicle speed, and determining the ratio of the difference to the vehicle speed as the slip rate;
[0050] Step 14: determine the first adhesion coefficient and the slip ratio as a set of data points.
[0051] In the specific example, the above steps 11 to 14 may refer to calculating the slip ratio and the first adhesion coefficient when the vehicle starts, that is, when the vehicle accelerates for the first time, a single tire is used as the observation object, that is, the output torque f and wheel speed v of a single tire are obtained in real time. ω , vehicle speed v , vertical force F z . And calculate the force of the tire on the ground Where r is the tire radius. Based on this, the slip rate and the first adhesion coefficient can be obtained by the following formula. The formula for determining the slip rate is: The formula for determining the adhesion coefficient is: And save this set of data points as (λ i , μ i). Through the above steps 11 to 14, the slip rate and the first adhesion coefficient of the road surface can be actually measured, and the force F of the tire on the ground can be calculated. xi , which provides relatively accurate data support for the subsequent determination of the coefficients in the target magic formula. xi With F x The meanings expressed are the same, the difference is that F xi is the actual measurement result, F x Calculated by the target magic formula.
[0052] In the embodiment of the present application, the values of the coefficients in the target magic formula are determined according to the data points actually measured, which can be determined by fitting the sampling points, specifically, finding the values of the parameters in the target magic formula so that the F obtained based on the target magic formula x Compared with the actual measured F xi The difference between them is minimal. It can be seen that in the embodiment of the present application, the values of each coefficient in the target magic are first determined, and then the corresponding adhesion coefficient is determined based on the target magic formula for determining the coefficient to control the vehicle. Based on this, the method involved in the above step 103 of determining the first adhesion coefficient of the current road surface according to the data points at different times and the target magic formula, and controlling the vehicle based on the second adhesion coefficient, can further include:
[0053] Step 21, determining the values of each coefficient in the target magic formula according to the data points at different times;
[0054] Step 22, determining a second adhesion coefficient based on a target magic formula for determining a coefficient value and data points at different times, and controlling the vehicle based on the second adhesion coefficient.
[0055] In the embodiment of the present application, the corresponding longitudinal force can be determined by the adhesion coefficient in the data point, so the values of each coefficient in the target magic formula can be obtained by substituting multiple longitudinal forces and multiple corresponding slip rates into the target magic formula. Further, in the embodiment of the present application, the method of determining the values of each coefficient in the target magic formula according to the data points at different times involved in step 21 in the above embodiment of the present application can further include:
[0056] Step 31, setting an error function, wherein the error function represents the sum of squares of the differences between the predicted values obtained by substituting all data points into the magic formula and the actual values;
[0057] Step 32, repeatedly iterating the values of each coefficient in the target magic formula by a numerical optimization method until the value of the error function is minimized;
[0058] Step 33: Determine the values of each coefficient in the target magic formula corresponding to the minimum value of the error function as the values of each coefficient in the target magic formula for determining the first adhesion coefficient.
[0059] For the above steps 31 to 33, in a specific example, the error function E may be first defined as the sum of squares of the differences between the predicted values and the actual values at all data points. The specific formula is as follows:
[0060]
[0061] Based on this, we first take the actual measured data points (λ i , μ i ), select the data point with the largest first adhesion coefficient, namely μ max Then determine the F corresponding to the maximum first adhesion coefficient. xi Furthermore, a set of values of each coefficient of the target magic formula can be initialized, and then the coefficients in the target magic formula can be adjusted based on numerical optimization methods, such as gradient descent method and conjugate gradient method. Through repeated iterations, a set of coefficients is obtained to minimize the value of the error function E, and the values of the set of coefficients are determined as the values of each coefficient in the target magic formula.
[0062] In the embodiment of the present application, after determining the values of each coefficient in the target magic formula, it is necessary to further verify whether the target magic formula is a truly applicable adhesion coefficient curve application. Therefore, in the embodiment of the present application, for the target magic formula based on the determined coefficient values and the data points at different times involved in the above step 22, the adhesion coefficient is determined, and the method of controlling the vehicle based on the adhesion coefficient may further include:
[0063] Step 41, determining the longitudinal force at the target moment based on the data point at the target moment and the target magic formula, and determining the second adhesion coefficient based on the ratio of the longitudinal force to the vertical force of the tire;
[0064] Step 42: When the difference between the determined second adhesion coefficient and the actually measured adhesion coefficient is less than a preset threshold, control the vehicle at a target time based on the determined second adhesion coefficient.
[0065] Through the above steps 41 and 42, after the values of the coefficients in the target magic formula are determined, the current longitudinal force can be determined from the current actual slip rate, and then the second adhesion coefficient of the road surface can be determined based on the longitudinal force and the vertical force of the tire. If the difference between the adhesion coefficient actually measured and the adhesion coefficient obtained according to the target magic formula exceeds the preset threshold, it indicates that the target magic formula does not apply to the current environment and the traditional calibration curve can be used. If the difference between the adhesion coefficients obtained according to the target magic formula does not exceed the preset threshold, it indicates that the current target magic formula is applicable to the current environment.
[0066] It can be seen that, through the above-mentioned method of the embodiment of the present application, compared with the traditional complex calibration method, the scheme in the embodiment of the present application simplifies the operation process, and only needs to simply optimize the existing magic formula, that is, add G x After the coefficient (target coefficient), add G x The magic formula after the coefficient is used to fit the sampling points, that is, the addition of G can be obtained through the minimum error function. x The values of the magic formula coefficients after the coefficients reduce the dependence on professional technicians, thereby reducing time and economic costs, making vehicle maintenance more efficient and economical.
[0067] In an optional implementation of the embodiment of the present application, the method of controlling the vehicle at the target time based on the determined adhesion coefficient involved in the above step 42 may further include:
[0068] Step 51, determining the adhesion of the vehicle tire based on the second adhesion coefficient;
[0069] Step 52, obtaining the slip rate of the road surface at the target time, and allocating corresponding torque to the vehicle tires at the target time based on the slip rate and adhesion.
[0070] In this regard, in a specific example, the torque of the vehicle wheels (e.g., four wheels) can be allocated respectively based on the current target magic formula and the actual expected slip rate and adhesion. Since the target magic formula in the embodiment of the present application can accurately estimate and adapt to different slip rates and road types, the performance of the vehicle in various environments can be improved, especially the performance under non-standard road conditions.
[0071] Corresponding to the above Figure 1 , the embodiment of the present application also provides a vehicle control device, such as Figure 4 As shown, the device comprises:
[0072] A first processing module 402 is used to modify the initial magic formula of the tire using a target coefficient to obtain a target magic formula, wherein the target coefficient is multiplied by a target result in the initial magic formula, and the target result is an arc tangent result of multiplying the slip rate by the stiffness factor; the target coefficient is used to decouple the curvature factor and the stiffness factor in the target magic formula;
[0073] The second processing module 404 is used to obtain the operating parameters at different times during the acceleration process after the vehicle starts, and determine the corresponding data points based on the operating parameters, wherein the data points include the slip rate and the first adhesion coefficient;
[0074] The third processing module 406 is used to determine the second adhesion coefficient of the road surface according to the data points at different times and the target magic formula, and control the vehicle based on the second adhesion coefficient.
[0075] Through the device of the embodiment of the present application, the target magic formula obtained by correcting the initial magic tire formula with the target coefficient pays attention to the difference between the front and rear ends of the slip rate, so that the curve accuracy of the target magic tire formula is closer to the road conditions, and it does not bring more complex computing power consumption. Therefore, after obtaining the operating parameters of the vehicle at different times during the acceleration process after starting, the corresponding data points are determined according to the operating parameters, and the coefficients of the target magic tire formula determined by the data points can then be used to more accurately identify the second adhesion coefficient of the current road surface according to the target magic formula. Therefore, when the second adhesion coefficient determined by the embodiment of the present application controls the vehicle, it can enhance the safety and stability of the vehicle under complex road conditions.
[0076] In an optional implementation manner of an embodiment of the present application, the second processing module in the embodiment of the present application may further include: an acquisition unit, used to acquire operating parameters of vehicle tires, wherein the operating parameters include: output torque, wheel speed, vehicle speed and vertical force; a first determination unit, used to determine the ratio of the output torque to the tire radius as the longitudinal force of the tire, and determine the ratio of the longitudinal force to the vertical force as the first adhesion coefficient; a second determination unit, used to determine the difference between the wheel speed and the vehicle speed, and determine the ratio of the difference to the vehicle speed as the slip rate; a third determination unit, used to determine the first adhesion coefficient and the slip rate as a set of data points.
[0077] In an optional implementation manner of an embodiment of the present application, the third processing module in the embodiment of the present application includes: a determination unit, used to determine the values of each coefficient in the target magic formula according to data points at different times; a processing unit, used to determine the first adhesion coefficient based on the target magic formula for determining the coefficient values and the data points at different times, and control the vehicle based on the second adhesion coefficient.
[0078] In an optional implementation manner of an embodiment of the present application, the determination unit in the embodiment of the present application may further include: a setting unit, used to set an error function, wherein the error function represents the sum of squares of differences between predicted values and actual values obtained by substituting all data points into the magic formula; a processing unit, used to repeatedly iterate the values of each coefficient in the target magic formula through a numerical optimization method until the value of the error function is minimized; a fourth determination unit, used to determine the values of each coefficient in the target magic formula corresponding to the minimum value of the error function as the values of each coefficient in the target magic formula for determining the adhesion coefficient.
[0079] In an optional implementation of the embodiment of the present application, the target magic formula obtained after the initial magic formula is modified by using the target coefficient is G x : F x =D x sin{C x arctan[B x λ-E x (B x λ-arctanB x λ)]}
[0080] The target magic formula is: F x =D x sin{C x arctan[B x λ-E x (B x λ-G x arctanB x λ)]}
[0081] Among them, F x represents the longitudinal force, x is the longitudinal slip rate, D x is the peak factor, C x is the shape factor, B x is the stiffness factor, E x is the curvature factor, λ is the slip rate; λ=x+Sh, Sh is the horizontal offset.
[0082] In an optional implementation manner of an embodiment of the present application, the processing unit in the embodiment of the present application may further include: a first determination subunit, used to determine the longitudinal force at the target moment based on the data points at the target moment and the target magic formula, and determine the adhesion coefficient based on the ratio of the longitudinal force to the vertical force of the tire; a second determination subunit, used to control the vehicle at the target moment based on the determined second adhesion coefficient when the difference between the determined second adhesion coefficient and the actually measured adhesion coefficient is less than a preset threshold.
[0083] In an optional implementation of an embodiment of the present application, the second determination subunit in the embodiment of the present application is also used to determine the adhesion of the vehicle tires based on the second adhesion coefficient; and to obtain the slip rate of the road surface at the target moment, and to allocate corresponding torque to the vehicle tires at the target moment based on the slip rate and adhesion.
[0084] like Figure 5 As shown, an embodiment of the present application provides an electronic device, including a processor 511, a communication interface 512, a memory 513 and a communication bus 514, wherein the processor 511, the communication interface 512, and the memory 513 communicate with each other through the communication bus 514.
[0085] Memory 513, used for storing computer programs;
[0086] In one embodiment of the present application, the processor 511 is used to execute the program stored in the memory 513 to implement the vehicle control method provided by any of the above method embodiments, including:
[0087] S1, using a target coefficient to correct an initial magic formula of the tire to obtain a target magic formula, wherein the target coefficient is multiplied by a target result in the initial magic formula, the target result is an arc tangent result of multiplying the slip rate by the stiffness factor, and the target coefficient is used to decouple the curvature factor and the stiffness factor in the target magic formula;
[0088] S2, obtaining operating parameters at different times during the acceleration process after the vehicle starts, and determining corresponding data points based on the operating parameters, wherein the data points include a slip rate and an adhesion coefficient;
[0089] S3, determines the adhesion coefficient of the road surface according to the data points at different times and the target magic formula, and controls the vehicle based on the adhesion coefficient.
[0090] It should be noted that the electronic device performs the above steps and plays the same role as the above embodiment of the present application. Figure 1 The functions of the method steps in are the same and will not be repeated here.
[0091] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the vehicle control method provided in any of the aforementioned method embodiments are implemented.
[0092] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0093] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course, by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the relevant technology can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.
[0094] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.
[0095] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A vehicle control method, characterized in that: include: The initial magic formula of the tire is corrected by using a target coefficient to obtain a target magic formula, wherein the target coefficient is multiplied by a target result in the initial magic formula, and the target result is an arc tangent result of multiplying the slip rate by the stiffness factor; the target coefficient is used to decouple the curvature factor and the stiffness factor in the target magic formula; Acquiring operating parameters at different times during the acceleration process after the vehicle starts, and determining corresponding data points based on the operating parameters, wherein the data points include a slip ratio and a first adhesion coefficient; The second adhesion coefficient of the current road surface is determined according to the data points at different times and the target magic formula, and the vehicle is controlled based on the second adhesion coefficient.
2. The method according to claim 1, characterized in that: Obtaining operating parameters at different times during the acceleration process after the vehicle starts, and determining corresponding data points based on the operating parameters includes: Acquiring operating parameters of vehicle tires, wherein the operating parameters include: output torque, wheel speed, vehicle speed and vertical force; Determine the ratio of the output torque to the tire radius as the longitudinal force of the tire, and determine the ratio of the longitudinal force to the vertical force as the first adhesion coefficient; determining a difference between the wheel speed and the vehicle speed, and determining a ratio of the difference to the vehicle speed as the slip ratio; The first adhesion coefficient and the slip ratio are determined as a set of the data points.
3. The method according to claim 1, characterized in that Determining a second adhesion coefficient of a current road surface according to data points at different times and the target magic formula, and controlling the vehicle based on the second adhesion coefficient includes: Determine the value of each coefficient in the target magic formula according to data points at different times; The second adhesion coefficient is determined based on a target magic formula for determining a coefficient value and data points at different times, and the vehicle is controlled based on the second adhesion coefficient.
4. The method according to claim 3, characterized in that The values of the coefficients in the target magic formula are determined according to the data points at different times, including: Setting an error function, wherein the error function represents the sum of squares of the differences between the predicted values and the actual values obtained by substituting all data points into the magic formula; Repeatedly iterating the values of each coefficient in the target magic formula by a numerical optimization method until the value of the error function is minimized; The values of the coefficients in the target magic formula corresponding to the minimum value of the error function are determined as the values of the coefficients in the target magic formula for determining the second adhesion coefficient.
5. The method according to claim 1, characterized in that The initial magic formula of the tire is corrected using the target coefficient, and the target magic formula includes: Add the target coefficient G to the following initial magic formula x : F x =D x sin{C x arcane[B x λ-E x (B x λ-arctane B x λ)]} Get the target magic formula: F x =D x sin{C x arcane[B x λ-E x (B x λ-G x silver B x λ)]} Among them, F x represents the longitudinal force, x is the longitudinal slip rate, D x is the peak factor, C x is the shape factor, B x is the stiffness factor, E x is the curvature factor, λ is the slip rate; λ=x+Sh, Sh is the horizontal offset.
6. The method according to claim 3, characterized in that Determining the second adhesion coefficient based on a target magic formula for determining a coefficient value and data points at different times, and controlling the vehicle based on the second adhesion coefficient includes: Determine the longitudinal force at the target moment based on the data point at the target moment and the target magic formula, and determine the second adhesion coefficient based on the ratio of the longitudinal force to the vertical force of the tire; When a difference between the determined second adhesion coefficient and the actually measured adhesion coefficient is less than a preset threshold, the vehicle is controlled at the target time based on the determined second adhesion coefficient.
7. The method according to claim 6, characterized in that Controlling the vehicle at the target time based on the determined second adhesion coefficient includes: determining adhesion of the vehicle tire based on the second adhesion coefficient; The slip rate of the road surface at the target time is obtained, and corresponding torque is allocated to the vehicle tire at the target time based on the slip rate and the adhesion.
8. A vehicle control device, characterized in that: include: A first processing module is used to modify an initial magic formula of a tire using a target coefficient to obtain a target magic formula, wherein the target coefficient is multiplied by a target result in the initial magic formula, and the target result is an arc tangent result of multiplying a slip rate by a stiffness factor; and the target coefficient is used to decouple a curvature factor and a stiffness factor in the target magic formula; a second processing module, configured to obtain operating parameters at different times during the acceleration process after the vehicle starts, and determine corresponding data points based on the operating parameters, wherein the data points include a slip ratio and a first adhesion coefficient; The third processing module determines a second adhesion coefficient of the road surface according to data points at different times and the target magic formula, and controls the vehicle based on the second adhesion coefficient.
9. An electronic device, comprising: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor coupled to the at least one bus; At least one memory connected to the at least one bus, wherein the processor is configured to execute the vehicle control method according to any one of claims 1 to 7. 10 . A computer storage medium storing computer executable instructions, wherein the computer executable instructions are used to execute the vehicle control method according to any one of claims 1 to 7.