Anti-skid control for vehicle

Abstract

An anti-skid control method and system for a vehicle, an automobile, and a computer-readable storage medium. The anti-skid control method for a vehicle comprises: acquiring an actual electric motor rotational speed of an electric motor of a vehicle (S1); determining a target electric motor rotational speed of the electric motor of the vehicle (S2); determining the slip state of wheels of the vehicle relative to the current road surface according to the actual electric motor rotational speed and the target electric motor rotational speed (S3); and determining the current adjustment amount of an actual electric motor torque of the electric motor of the vehicle according to the slip state of the wheels of the vehicle relative to the current road surface, and determining an adjusted electric motor drive torque according to the current adjustment amount so as to adjust the actual electric motor rotational speed of the electric motor of the vehicle, such that the actual electric motor rotational speed reaches the target electric motor rotational speed (S4). The method has a rapid and accurate recognition process, a short active anti-skid control link, a short control period and a better anti-skid control effect.

Description

Vehicle anti-skid control

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on August 3, 2023, with application number 202310971225.0, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The embodiments of the present application relate to, but are not limited to, the field of vehicle technology, and in particular relate to, but are not limited to, a vehicle anti-skid control method, system, automobile, and computer-readable storage medium. Background Art

[0004] When a vehicle enters a low-adhesion road surface while driving, the wheels are prone to excessive slip or skidding, which will greatly affect the stability and safety of the vehicle, and at the same time affect the vehicle's acceleration performance and deceleration and braking capabilities.

[0005] Summary of the Invention

[0006] 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. This application provides a vehicle anti-skid control method, system, vehicle, and computer-readable storage medium that can meet the requirements of vehicle wheel anti-skid control.

[0007] The present application provides a vehicle anti-skid control method, comprising:

[0008] Obtaining an actual motor speed of the vehicle;

[0009] Obtaining the current speed of the vehicle;

[0010] determining an actual slip rate of the vehicle according to the actual motor speed and the current vehicle speed;

[0011] Obtaining an actual utilized adhesion coefficient of the vehicle;

[0012] determining an optimal slip ratio of the vehicle according to the actual slip ratio and the actual utilized adhesion coefficient;

[0013] determining a target speed of a motor of the vehicle according to an optimal slip ratio of the vehicle;

[0014] Determining a slip state of the vehicle based on the actual motor speed and the target motor speed; and

[0015] According to the slip state of the vehicle, a current adjustment amount for the motor driving torque of the vehicle is determined, and the adjusted motor driving torque is determined according to the current adjustment amount, so that the actual speed of the motor of the vehicle reaches the target speed of the motor.

[0016] In some embodiments, obtaining the current speed of the vehicle includes:

[0017] Obtaining the speed of the vehicle's wheels, the acceleration of the vehicle body, and the steering wheel angle; and

[0018] The current speed of the vehicle is determined based on the speed of the vehicle's wheels, the acceleration of the vehicle body, and the steering wheel angle.

[0019] In some embodiments, determining the actual slip rate of the vehicle based on the actual motor speed and the current vehicle speed includes:

[0020] The actual slip rate of the vehicle is determined according to a ratio of the actual rotational speed of the motor to a product of the current vehicle speed and a transmission ratio of a transmission system of the vehicle.

[0021] In some embodiments, obtaining the actual utilized adhesion coefficient of the vehicle includes:

[0022] Obtaining the current vertical load and longitudinal driving force of the vehicle; and

[0023] The actual utilized adhesion coefficient of the vehicle is determined according to the ratio of the current longitudinal driving force of the vehicle to the vertical load.

[0024] In some embodiments, determining the optimal slip rate of the vehicle according to the actual slip rate and the actual utilized adhesion coefficient includes:

[0025] determining whether the actual slip rate is greater than a slip rate threshold;

[0026] If the actual slip ratio is less than the slip ratio threshold, determining the actual slip ratio as an optimal slip ratio of the vehicle;

[0027] If the actual slip rate is greater than the slip rate threshold, determining a plurality of weight coefficients of the current road surface relative to the plurality of standard road surfaces by comparing the actual slip rate and the actual utilized adhesion coefficient with pre-stored standard slip rates and standard utilized adhesion coefficients of the plurality of standard road surfaces; and

[0028] An optimal slip ratio of the vehicle is determined according to a plurality of weight coefficients of the current road surface relative to the plurality of standard road surfaces.

[0029] In some embodiments, determining the optimal slip ratio of the vehicle based on a plurality of weight coefficients of the current road surface relative to the plurality of standard road surfaces includes:

[0030] The optimal slip rate of the vehicle is determined as the ratio of the sum of the products of the standard slip rate of each standard road surface and its corresponding weight coefficient to the sum of multiple weight coefficients of the current road surface relative to the multiple standard road surfaces.

[0031] In some embodiments, determining the target speed of the motor of the vehicle according to the optimal slip ratio of the vehicle includes:

[0032] A target speed of a motor of the vehicle is determined according to the current vehicle speed, a transmission ratio of a transmission system of the vehicle, and the optimal slip ratio.

[0033] In some embodiments, determining the target speed of the motor of the vehicle further includes:

[0034] determining a correction amount for the target motor speed according to a product of a rate of change of the motor drive torque of the vehicle and a deformation coefficient of a transmission system of the vehicle; and

[0035] The motor target speed is corrected according to the correction amount of the motor target speed to determine the corrected motor target speed as the motor target speed of the vehicle.

[0036] In some embodiments, determining the slip state of the vehicle based on the actual motor speed and the target motor speed includes:

[0037] Determining a motor speed deviation value of the vehicle according to the motor target speed and the motor actual speed of the vehicle;

[0038] Determining a rate of change of the motor speed deviation value according to the motor speed deviation value;

[0039] The slip state of the vehicle is determined according to the motor speed deviation value and the rate of change of the motor speed deviation value.

[0040] In some embodiments, determining the slip state of the vehicle based on the motor speed deviation value and the rate of change of the motor speed deviation value of the vehicle includes one of the following:

[0041] When the motor speed deviation value is greater than 0 and the rate of change of the motor speed deviation value is greater than or equal to 0, determining that the slip state is an aggravated slip state;

[0042] When the motor speed deviation value is greater than 0 and the rate of change of the motor speed deviation value is less than 0, determining that the slip state is a slip callback state;

[0043] When the motor speed deviation value is less than 0 and the rate of change of the motor speed deviation value is greater than 0, determining that the slip state is a slip increase state;

[0044] When the motor speed deviation value is less than 0 and the rate of change of the motor speed deviation value is greater than or equal to 0, determining that the slip state is an aggravated slip state; or

[0045] When the motor speed deviation value is equal to 0 and the rate of change of the motor speed deviation value is an arbitrary value, it is determined that the slip state is the optimal slip state.

[0046] In some embodiments, determining a current adjustment amount for a motor drive torque of the vehicle based on the slip state, and determining an adjusted motor drive torque based on the current adjustment amount so as to enable the actual motor speed of the vehicle to reach the target motor speed includes:

[0047] determining a current adjustment amount for a motor drive torque of the vehicle according to a slip state of the vehicle;

[0048] Determine the minimum value of the sum of the motor request torque of the vehicle, the current adjustment amount, and the motor request torque as the adjusted motor drive torque; and

[0049] According to the adjusted motor driving torque, the actual speed of the motor of the vehicle is adjusted to reach the target speed of the motor.

[0050] In some embodiments, when the vehicle switches between different slip states, the vehicle anti-skid control method further includes:

[0051] An initial switching value of the motor driving torque when the motor of the vehicle switches between different slip states is configured.

[0052] In some embodiments, configuring the initial value of the motor driving torque when the motor of the vehicle switches between different slip states includes:

[0053] The switching initial value of the motor driving torque is determined according to the adjusted motor driving torque at a previous moment of switching, the motor request torque at the time of switching, and the motor speed deviation value at the time of switching.

[0054] The present application also provides a computer-readable storage medium having a program stored thereon. When the program is executed by a processor, the vehicle anti-skid control method as described in any one of the above embodiments is implemented.

[0055] The present application also provides a vehicle anti-skid control system, comprising: one or more processors for implementing the vehicle anti-skid control method as described in any one of the above embodiments.

[0056] The present application also provides a vehicle, comprising: a vehicle anti-skid control system as described in the above embodiments.

[0057] The vehicle anti-skid control method, system, automobile and computer-readable storage medium of the embodiments of the present application. The vehicle anti-skid control method determines the vehicle's slip state by obtaining the actual motor speed of the vehicle and determining the target motor speed of the vehicle. Then, based on the vehicle's slip state, the current adjustment amount for the vehicle's motor drive torque is determined, so that the actual motor speed reaches the motor target speed by adjusting the motor drive torque according to the current adjustment amount. Among them, the vehicle's actual slip rate and the actual utilization adhesion coefficient are used to determine the vehicle's optimal slip rate, and then the vehicle's motor target speed is determined based on the vehicle's optimal slip rate, so that the acquired motor target speed is more accurate and the anti-skid control is more accurate. Moreover, the slip state is determined based on the actual motor speed and the motor target speed, and the identification process is fast and accurate, so that active anti-skid control can be achieved. The active anti-skid control link is short, the control cycle is short, and it has better control effect, meeting the anti-skid control requirements.

[0058] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG1 is a flowchart showing the steps of an embodiment of a vehicle anti-skid control method of the present application.

[0060] FIG2 is a flowchart showing the specific steps of step S2 of the vehicle anti-skid control method shown in FIG1 .

[0061] FIG3 is a flowchart showing an embodiment of step S3 of the vehicle anti-skid control method shown in FIG1 .

[0062] FIG. 4 is a graph showing an embodiment of the slip state of the vehicle of the present application.

[0063] FIG5 is a flowchart showing an embodiment of step S4 of the vehicle anti-skid control method shown in FIG1 .

[0064] FIG6 is a schematic diagram showing an embodiment of a vehicle anti-skid control system of the present application. DETAILED DESCRIPTION

[0065] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0066] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. Unless otherwise defined, technical or scientific terms used in this application should have the ordinary meaning understood by a person of ordinary skill in the art to which this application belongs. The terms "first," "second," and similar words used in this specification and claims do not denote any order, quantity, or importance, but are simply used to distinguish different components. Similarly, the terms "a" or "an" and similar words do not denote a limitation of quantity, but rather indicate the presence of at least one. The terms "plurality" or "several" mean at least two. Unless otherwise indicated, the terms "front," "rear," "lower," and / or "upper" and similar words are for convenience only and are not intended to limit to a single position or spatial orientation. The terms "include" or "comprising" and similar words mean that the elements or objects listed before "include" or "comprising" include the elements or objects listed after "include" or "comprising" and their equivalents, and do not exclude other elements or objects. The terms "connected" or "connected" and similar words are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect.

[0067] As used in this specification and the appended claims, the singular forms "a," "an," "said," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0068] When a vehicle enters a low-adhesion road surface, it is prone to excessive wheel slip or skidding, which can significantly affect the vehicle's stability and safety, as well as its acceleration performance and deceleration braking capabilities. The relevant vehicle's drive anti-skid control system issues a torque reduction output command to the motor drive after detecting the vehicle's wheel slip. The signal transmission link time causes signal lag, resulting in an excessive control cycle, which can lead to a rapid increase in slip rate and a sharp decrease in wheel lateral adhesion, causing sideslip and instability, seriously affecting driving safety and failing to meet the vehicle's wheel anti-skid control requirements.

[0069] The present application provides a vehicle anti-skid control method, system, vehicle, and computer-readable storage medium. The vehicle anti-skid control method includes: obtaining an actual motor speed of a vehicle; determining a target motor speed of the vehicle; determining a vehicle slip state based on the actual motor speed and the target motor speed; and determining a current adjustment amount of the vehicle's motor drive torque based on the vehicle slip state, and determining an adjusted motor drive torque based on the current adjustment amount to bring the actual motor speed of the vehicle to the target motor speed.

[0070] The vehicle anti-skid control method, system, automobile and computer-readable storage medium of the embodiments of the present application. The vehicle anti-skid control method determines the slip state of the vehicle by obtaining the actual motor speed of the vehicle and determining the target motor speed of the vehicle, and then determines the current adjustment amount of the vehicle's motor drive torque based on the slip state, and makes the actual motor speed of the vehicle reach the target motor speed by determining the adjusted motor drive torque based on the current adjustment amount. The present application determines the slip state based on the actual motor speed and the target motor speed. The process of determining the slip state is fast and accurate, so that active anti-skid control can be achieved. By using the vehicle anti-skid control method, the active anti-skid control link is short, the control cycle is short, and it has a better anti-skid control effect, meeting the anti-skid control requirements.

[0071] Figure 1 is a flowchart showing the steps of an embodiment of a vehicle anti-skid control method of the present application. As shown in Figure 1 , the vehicle anti-skid control method includes steps S1 to S4.

[0072] Step S1: Acquire the actual motor speed of the vehicle. The actual motor speed represents the current actual motor speed of the vehicle.

[0073] Step S2: Determine the target motor speed of the vehicle. The target motor speed represents the target motor speed that the vehicle's motor is intended to achieve, at which the vehicle's wheels will not slip on the ground (hereinafter also referred to as the road surface).

[0074] Step S3: Determine the vehicle's slip state based on the actual motor speed and the motor's target speed. The vehicle's slip state, i.e., the different slip states between the vehicle's wheels and the current road surface, can be determined based on the actual motor speed and the motor's target speed. For example, when the actual motor speed is greater than the motor's target speed, the vehicle's wheels are in a first slip state with the current road surface. When the actual motor speed is less than the motor's target speed, the vehicle's wheels are in a second slip state with the current road surface.

[0075] Step S4: Determine the current adjustment amount of the motor drive torque of the vehicle based on the vehicle's slip state, and determine the adjusted motor drive torque based on the current adjustment amount, thereby adjusting the actual motor speed to the target motor speed. The current adjustment amount of the motor drive torque varies depending on the vehicle's slip state. Determining the current adjustment amount of the motor drive torque based on the slip state allows for more rapid and accurate determination of the current adjustment amount.

[0076] The vehicle anti-skid control method of an embodiment of the present application determines the vehicle's slip state by obtaining the vehicle's actual motor speed and determining the vehicle's target motor speed. Based on the slip state, the current adjustment amount of the vehicle's motor drive torque is then determined. The adjusted motor drive torque is determined based on the current adjustment amount to bring the vehicle's actual motor speed to the motor's target speed. The present application determines the slip state based on the motor's actual speed and target speed. The process of determining the slip state is fast and accurate, thus enabling active anti-skid control. By applying this vehicle anti-skid control method, the active anti-skid control link is short, the control cycle is short, and better anti-skid control effects are achieved, meeting anti-skid control requirements.

[0077] In the embodiment shown in FIG. 1 , step S2 includes steps S21 to S25 .

[0078] Step S21: Obtain the current speed of the vehicle.

[0079] Step S22: Determine the actual slip rate of the vehicle based on the actual motor speed and the current vehicle speed.

[0080] Step S23: Obtain the actual utilization adhesion coefficient of the vehicle.

[0081] Step S24: Determine the optimal slip rate of the vehicle according to the actual slip rate and the actual utilized adhesion coefficient.

[0082] Step S25: Determine the target motor speed of the vehicle according to the optimal slip ratio of the vehicle.

[0083] With this setting, the vehicle's actual slip rate and the actual utilized adhesion coefficient are used to determine the vehicle's optimal slip rate, and then the vehicle's motor target speed is determined based on the vehicle's optimal slip rate, making the obtained motor target speed more accurate and the anti-skid control more accurate.

[0084] Fig. 2 is a flowchart showing the specific steps of step S2 of the vehicle anti-skid control method shown in Fig. 1. In combination with Fig. 1 and Fig. 2, step S21 includes steps S211 to S212.

[0085] Step S211: Acquire the speed of the vehicle's wheels, the acceleration of the vehicle body, and the steering wheel angle.

[0086] Step S212: Determine the current speed of the vehicle based on the speed of the vehicle's wheels, the acceleration of the vehicle body, and the steering wheel angle.

[0087] In this embodiment, the vehicle speed can be estimated based on the wheel speeds of the four wheels of the vehicle, the acceleration of the vehicle's inertial unit, and the steering wheel angle. b (t) is used to represent the estimated current speed of the vehicle. This speed is the current speed of the vehicle.

[0088] Step S22 includes step S221.

[0089] Step S221: Determine the actual slip rate of the vehicle based on the ratio of the actual motor speed to the product of the current vehicle speed and the transmission ratio of the vehicle's transmission system.

[0090] In this embodiment, the actual slip ratio λ(t) is used to represent the degree of slip of the vehicle's wheels relative to the current road surface. The slip ratio measures the degree of slip of the vehicle's wheels relative to the current road surface. A larger slip ratio indicates a greater degree of slip, while a smaller slip ratio indicates a smaller degree of slip.

[0091] In this embodiment, the actual slip ratio λ(t) is expressed by expression (1):

[0092] Among them, λ(t) is used to represent the actual slip rate of the vehicle; ω m (t) is used to indicate the actual speed of the vehicle's motor; V b (t) is used to indicate the current speed of the vehicle; i g Used to indicate the gear ratio of a vehicle's drivetrain.

[0093] With this arrangement, the actual slip ratio λ(t) of the vehicle can be obtained quickly and accurately through the above expression (1).

[0094] Step S23 includes step S231 to step S232.

[0095] Step S231: Obtain the current vertical load and longitudinal driving force of the vehicle.

[0096] Step S232: Determine the actual utilized adhesion coefficient of the vehicle based on the ratio of the current longitudinal driving force of the vehicle to the vertical load.

[0097] In this embodiment, the actual utilization adhesion coefficient of the vehicle is obtained by the ratio of the current longitudinal driving force of the vehicle to the vertical load. The actual utilization adhesion coefficient is expressed by expression (2):

[0098] Among them, μ(t) is used to represent the actual utilization adhesion coefficient of the vehicle; F z (t) is used to represent the current vertical load force of the vehicle; F x (t) is used to represent the current longitudinal driving force of the vehicle.

[0099] In this embodiment, the vehicle's current vertical load refers to the vertical force acting on the vehicle's wheels, also known as wheel force. It is determined by the vehicle's own weight and other wheel parameters. The vehicle's current longitudinal driving force refers to the force acting in the longitudinal direction of the vehicle's length, which propels the vehicle forward or restrains it from moving backward. Longitudinal driving force has a significant impact on the vehicle's acceleration, deceleration, and traction capabilities.

[0100] In this embodiment, F z (t) represents the current vertical load force of the vehicle, expressed as F x (t) represents the current longitudinal driving force of the vehicle. x (t) is expressed by expression (3):

[0101] Among them, T m Used to indicate the motor drive torque of the vehicle; J m Used to represent the vehicle's motor moment of inertia; ω m It is used to indicate the actual speed of the vehicle's motor; Δt is used to indicate unit time; Used to indicate the rate of change of the vehicle's motor speed, that is, the motor acceleration; i g Used to indicate the transmission ratio of the vehicle's transmission system; T f Used to express the rolling resistance torque of the vehicle's wheels; J w Used to represent the moment of inertia of the vehicle's wheels; R w Used to represent the rolling radius of a vehicle's wheels.

[0102] With this setting, the actual utilization adhesion coefficient of the vehicle is mainly based on the actual speed of the vehicle's motor ω m , the vehicle's motor acceleration and the rolling resistance torque T of the vehicle's wheels f Sure.

[0103] Furthermore, different vehicle anti-skid control methods are selected based on different numerical ranges of the slip rate under the current road surface and current driving conditions.

[0104] Step S24 includes step S241 to step S242.

[0105] Step S241: Determine whether the actual slip ratio is greater than a slip ratio threshold. In this embodiment, the slip ratio threshold is, for example, 3%.

[0106] In some embodiments, if the actual slip rate is less than a slip rate threshold, the actual slip rate is determined to be the optimal slip rate. In this embodiment, if the actual slip rate is less than 3%, the current actual slip rate is determined to be the optimal slip rate. When the slip rate of the current road surface is very small, i.e., λ(t) < 3%, the difference in the adhesion coefficient between different road surfaces is small, making it difficult to distinguish between different road surfaces. In this case, no slip rate control intervention is required. Therefore, the current road surface is assumed to have the best road adhesion conditions, i.e., the current road surface is the best road surface. The optimal slip rate under this best road surface can be used as the optimal slip rate for the current road surface.

[0107] In some embodiments, if the actual slip rate is greater than a slip rate threshold (for example, greater than 3%), the actual slip rate, the actual utilized adhesion coefficient, and the pre-stored standard slip rates and standard utilized adhesion coefficients of multiple standard road surfaces are compared to determine multiple weight coefficients of the current road surface relative to the multiple standard road surfaces.

[0108] In this embodiment, when the actual slip rate is significantly larger, for example, λ(t) ≥ 3%, the actual slip rate and the usable adhesion coefficient are compared with the slip rates and the standard usable adhesion coefficients of eight pre-stored standard road surfaces to calculate the weight coefficients between the current road surface and the eight standard road surfaces. The weight coefficients are used to represent the similarity between the current road surface and the eight standard road surfaces. The weight coefficients are expressed by expression (4):

[0109] Among them, ε i (t) is the weight coefficient of the current road surface compared with the i-th road surface at the current time t; μ(t) is the utilization adhesion coefficient of the current road surface at the current time t; μ i (t) is the adhesion coefficient on the i-th road surface under the current slip rate input on the current road surface at the current time t; δ is a very small positive number to avoid the denominator being zero.

[0110] With this setting, the actual slip rate and utilization adhesion coefficient of the current road surface are compared with the slip rates and standard utilization adhesion coefficients of eight pre-stored standard road surfaces to obtain the similarity between the current road surface and any one of the eight standard road surfaces.

[0111] Step S242: Determine the optimal slip ratio of the vehicle based on the weight coefficients of the current road surface relative to the various standard road surfaces. In step S242, the optimal slip ratio of the vehicle is determined based on the ratio of the sum of the products of the standard slip ratio of each standard road surface and the weight coefficient corresponding to that standard road surface to the sum of the weight coefficients of the current road surface and the standard road surface.

[0112] In this embodiment, the optimal slip ratio corresponding to the current road is determined based on the eight weight coefficients calculated between the current road surface and the eight standard road surfaces. The optimal slip ratio is expressed by expression (5):

[0113] Among them, λ opt (t) is used to represent the optimal slip ratio of the vehicle; ∑ε i (t)λ opt It is used to represent the sum of the products of the standard slip rate of each standard road surface among the eight standard road surfaces and the weight coefficient corresponding to the standard road surface; ∑ε i (t) is used to represent the sum of multiple weight coefficients of the current road surface relative to the standard road surface.

[0114] With this setting, the optimal slip rate of the vehicle can be determined more accurately by calculating the ratio of the sum of the products of the standard slip rate of each standard road surface and the weight coefficient corresponding to the standard road surface to the sum of multiple weight coefficients of the current road surface relative to the standard road surface.

[0115] Further, step S25 includes step S251.

[0116] Step S251: Determine the target speed of the motor of the vehicle according to the current vehicle speed, the transmission ratio of the vehicle's transmission system, and the optimal slip ratio.

[0117] In this embodiment, the motor target speed refers to the motor speed corresponding to the wheel speed when the vehicle's wheels are in the optimal slip state. The motor target speed is expressed by expression (6):

[0118] in, Used to indicate the target speed of the vehicle's motor; opt (t) is used to represent the optimal slip ratio of the vehicle; V b (t) is used to indicate the current speed of the vehicle; i g Used to indicate the gear ratio of a vehicle's drivetrain.

[0119] Since the power transmission between the vehicle's motor and wheels is not completely rigidly connected, it is necessary to consider the speed error caused by the elastic deformation of the transmission system's shaft system during torque loading. Therefore, this embodiment can correct the motor's target speed.

[0120] In the embodiment shown in FIG. 2 , after determining the target speed of the motor of the vehicle, the vehicle anti-skid control method further includes steps S26 to S27 .

[0121] Step S26 : Determine a correction amount for the motor target speed based on the product of the rate of change of the motor drive torque of the vehicle and the deformation coefficient of the transmission system of the vehicle.

[0122] Step S27 : Correcting the motor target speed according to the correction amount of the motor target speed to determine the corrected motor target speed as the motor target speed of the vehicle.

[0123] In this embodiment, when the motor target speed is corrected, only the motor torque loading process and the process in which the motor torque maintains a stable value are corrected. The motor torque unloading process is not corrected. During the motor torque loading process and the motor torque stable output process, the rate of change of the motor's actual output torque is multiplied by the deformation coefficient of the transmission system as the correction amount for the motor target speed. The correction amount for the motor target speed is expressed by expression (7):

[0124] Among them, T m (t) is used to represent the vehicle's motor driving torque; LPF (T m ) is used to indicate T m (t) is subjected to first-order low-pass filtering; ΔT is used to represent the time constant of the first-order low-pass filtering; K(t) is used to represent the deformation coefficient of the vehicle's transmission system, which can be obtained through actual vehicle calibration when used in actual vehicle applications.

[0125] The corrected motor target speed is obtained according to expressions (6) and (7), which is expressed by expression (8):

[0126] With this configuration, the corrected motor target speed of the vehicle can be determined based on the motor target speed and the correction amount of the motor target speed, so that the corrected motor target speed can be more accurate.

[0127] Fig. 3 is a flowchart showing an embodiment of step S3 of the vehicle anti-skid control method shown in Fig. 1. Referring to Fig. 1 to Fig. 3, step S3 includes steps S31 to S33.

[0128] Step S31 : determining a motor speed deviation value of the vehicle according to the corrected motor target speed and the actual motor speed of the vehicle.

[0129] Step S32: Determine the rate of change of the motor speed deviation value according to the motor speed deviation value.

[0130] Step S33: Determine the slip state of the vehicle according to the motor speed deviation value and the change rate.

[0131] In this embodiment, the slip state is determined based on the motor speed deviation between the actual motor speed and the target motor speed, and the rate of change of the motor speed deviation. The motor speed deviation is represented by expression (9):

[0132] Wherein, e(t) is used to represent the motor speed deviation value between the actual motor speed and the target motor speed at time t; ω m (t) is used to indicate the actual speed of the vehicle's motor; Used to indicate the corrected motor target speed of the vehicle.

[0133] The rate of change of the motor speed deviation is expressed by expression (10):

[0134] in, It is used to represent the rate of change of the motor speed deviation at time t; e(t) is used to represent the motor speed deviation between the actual motor speed and the corrected motor target speed at time t; LPF(e(t)) is used to represent the first-order low-pass filtering processing of e(t); ΔT is used to represent the time constant of the first-order low-pass filter.

[0135] With this setting, based on the calculated motor speed deviation value e(t) and the motor speed deviation value change rate The slip state of the vehicle's wheels at the current time t can be determined. The corresponding relationship between the specific slip state, the motor speed deviation value, and the motor speed deviation value change rate is shown in the following table:

[0136] Table 1: Correspondence between slip state, speed deviation value, and motor speed deviation value change rate

[0137] FIG4 is a graph illustrating an embodiment of a vehicle slip state according to the present application. In the embodiment shown in FIG4 and Table 1, in step S33, when the motor speed deviation value of the vehicle is greater than 0 and the rate of change of the motor speed deviation value is greater than or equal to 0, the vehicle slip state is determined to be an aggravated slip state.

[0138] In the embodiment shown in FIG. 4 and Table 1, in step S33 , when the motor speed deviation value of the vehicle is greater than 0 and the rate of change of the motor speed deviation value is less than 0, it is determined that the slip state of the vehicle is a slip callback state.

[0139] In the embodiment shown in FIG. 4 and Table 1, in step S33 , when the motor speed deviation value of the vehicle is less than 0 and the rate of change of the motor speed deviation value is greater than 0, it is determined that the slip state of the vehicle is a slip-increasing state.

[0140] In the embodiment shown in FIG. 4 and Table 1, in step S33 , when the motor speed deviation value of the vehicle is less than 0 and the rate of change of the motor speed deviation value is greater than or equal to 0, it is determined that the slip state of the vehicle is an aggravated slip state.

[0141] In the embodiment shown in FIG. 4 and Table 1, in step S33 , when the motor speed deviation value of the vehicle is equal to 0 and the rate of change of the motor speed deviation value is any value, it is determined that the slip state of the vehicle is the optimal slip state.

[0142] When the actual motor speed exceeds the target motor speed, it indicates that the vehicle's wheels are in a state of excessive slip. At this point, intervention is required on the motor drive torque to reduce the motor drive torque to prevent further aggravation of the slip, which would affect the stability and safety of the vehicle. In this embodiment, the motor torque command is adjusted based on the deviation between the actual motor speed and the corrected target motor speed. The motor torque command outputs the actual motor torque after the motor responds, and then acts on the vehicle system driven by the motor. Only then does the motor speed response change. Coupled with the influence of the inertia of the moving parts, the response of the motor speed regulation has a large lag. Therefore, in order to achieve a fast and stable active anti-skid control effect, a segmented PI (Proportional-Integral) control algorithm is adopted to determine the slip state of the wheel. Based on different slip states, different PI parameters are called, so that the torque output of the motor can be adjusted quickly and accurately.

[0143] Fig. 5 is a flowchart showing an embodiment of step S4 of the vehicle anti-skid control method shown in Fig. 1. Referring to Fig. 1 to Fig. 5, step S4 includes steps S41 to S43.

[0144] Step S41: Determine a current adjustment amount of the motor driving torque of the vehicle according to the slip state of the vehicle.

[0145] Step S42 : Determine the minimum value of the sum of the motor request torque of the vehicle, the current adjustment amount, and the motor request torque as the adjusted motor drive torque.

[0146] Step S43: According to the adjusted motor driving torque, the actual motor speed of the vehicle is adjusted to reach the motor target speed.

[0147] In this embodiment, based on the determined slip state of the vehicle, PI combination values ​​under different slip states are selected, and the motor drive torque is adjusted based on the motor speed deviation value e(t) until the slip state is exited, for example, until the actual slip rate of the vehicle is less than the slip rate threshold.

[0148] When the actual motor speed exceeds the target motor speed, it is determined that the wheel is experiencing excessive slip, and active anti-skid control is initiated. During active anti-skid control, a PI combination value is selected for each slip state. This PI combination value represents the current adjustment for the vehicle's motor drive torque. The motor drive torque is the driving torque used to drive and adjust the actual motor speed. Wheel slip typically occurs when the motor drive torque is excessive. Preventing slip requires appropriately reducing the motor drive torque. Typically, this motor drive torque is the driver's torque request, or the motor request torque. However, slip only occurs when the motor request torque exceeds the road surface adhesion. Therefore, the adjusted motor drive torque is determined based on the minimum of the sum of the vehicle's motor request torque, the current adjustment for the motor drive torque, and the motor request torque, thereby adjusting the vehicle's actual motor speed to the target motor speed.

[0149] The adjusted motor drive torque is expressed by expression (11): int =min ((Tq req +P*I*e(t)),Tq req ); (11)

[0150] Among them, Tq int Used to represent the adjusted motor drive torque of the vehicle; Tq req It is used to represent the vehicle's motor drive torque, that is, the motor request torque set by the driver; P and I are used to represent the proportional coefficient and integral coefficient of the motor speed deviation value e(t), respectively; P*I*e(t) is used to represent the current adjustment value for the motor drive torque; min is the minimum operation function.

[0151] With this setting, under different slip states, by calling different PI parameter groups, the vehicle can be quickly stabilized from an unstable state due to excessive slip.

[0152] In some embodiments, when a vehicle switches between different slip states, the vehicle anti-skid control method further includes configuring an initial switching value for the motor drive torque of the vehicle's motor when switching between the different slip states. In some embodiments, configuring the initial switching value for the motor drive torque of the vehicle's motor when switching between the different slip states includes determining the initial switching value for the motor drive torque of the vehicle's motor when switching between the slip states based on the adjusted motor drive torque immediately before the slip state switching, the motor request torque at the time of the switching, and the motor speed deviation at the time of the switching.

[0153] In order to ensure the smoothness of the motor torque output when the vehicle switches between different slip states and avoid sudden changes or steps in torque due to the selection of different PI parameters when switching between slip states during motor torque adjustment, the I item needs to be assigned an initial value when switching the slip state to ensure smooth connection of the motor torque command when switching between different slip states.

[0154] The discretization of the above formula (11) is expressed by expression (12):

[0155] Among them, I0 is used to represent the initial value of the I item. When the slip state remains unchanged, this value remains unchanged; when the slip state switches, the I0 item is reset; when the slip state switches, the initial value I0 of the I item is reset to ensure smooth connection of the motor torque output.

[0156] The initial value I0 of the I term is expressed by expression (13): I0 = Tq int (n-1)-Tq req (n)-P*e(n); (13)

[0157] Among them, Tq int (n-1) is used to represent the adjusted motor drive torque at the previous moment when the slip state is switched; Tq req (n) is used to indicate the motor torque requested when the slip state is switched; e(n) is used to indicate the motor speed deviation at the moment of slip state switching.

[0158] By actively adjusting the electric drive torque output and stabilizing the actual motor speed at the set motor target speed, the wheels can be operated at the optimal slip rate state, maximizing the utilization of wheel-road adhesion and maximizing the driving torque requirements of the vehicle's anti-skid control.

[0159] In some embodiments, when the regulated motor drive torque Tq of the vehicle's motor int Less than or equal to the vehicle's motor request torque Tq req , and when the slip state is not in the slip aggravation or slip callback state, it indicates that active anti-skid control is no longer needed at this time, and the vehicle exits active anti-skid control.

[0160] The vehicle anti-skid control method of this embodiment can determine the vehicle's slip state more quickly and accurately based on the actual motor speed and the motor target speed. Based on the actual motor speed and the motor target speed, active anti-skid control is implemented, thereby achieving optimal slip rate control. According to the above settings, the signal transmission link of the vehicle's active anti-skid control is short, the control adjustment cycle is short, and a better anti-skid control effect can be achieved. And based on the slip state, a segmented PI algorithm is adopted to adjust the motor drive torque, which can quickly and stably control the wheels to achieve the optimal slip rate. The motor drive torque responds quickly. When the motor-driven vehicle slips, the wheel slip is suppressed by reducing the motor torque, and the anti-skid control effect is better. A better anti-skid control effect can be obtained, while ensuring the power of the vehicle, while improving the stability and safety of the vehicle.

[0161] The present application also provides a computer-readable storage medium having a program stored thereon. When the program is executed by a processor, it implements the vehicle anti-skid control method as shown in the embodiments of Figures 1 to 5 above. In some embodiments, the computer-readable storage medium can be an internal storage unit of the aforementioned vehicle, such as a hard disk or memory. The computer-readable storage medium can also be an external storage device of the vehicle, such as a plug-in hard disk, a smart media card (SMC), an SD card, a flash card, etc. equipped with the device. Furthermore, the computer-readable storage medium can also include both an internal storage unit of the vehicle and an external storage device. The computer-readable storage medium is used to store computer programs and other programs and data required by the vehicle, and can also be used to temporarily store data that has been output or is about to be output. From a hardware perspective, as shown in Figure 6, a hardware structure diagram of a vehicle in which the processor of the present application is located is shown. In addition to the processor 601, memory 602, network interface 603, and non-volatile memory 604 shown in Figure 6, the vehicle in which the projection system is located in the embodiment can generally include other hardware based on the actual function of the vehicle, which will not be described in detail.

[0162] The present application also provides a vehicle anti-skid control system, comprising: one or more processors for implementing a vehicle anti-skid control method as in any one of the above-mentioned embodiments. For the system embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to the partial description of the method embodiments. The system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the technical solution of the present application. Those skilled in the art can understand and implement the technical solution of the present application without paying any creative work.

[0163] This application also provides a vehicle, including a vehicle anti-skid control system. The vehicle anti-skid control system is used to implement the vehicle anti-skid control method described in any one of Figures 1 to 5 . This application determines the slip state based on the actual motor speed and the target motor speed. This determination process is fast and accurate, thus enabling active anti-skid control of the vehicle. The active anti-skid control has a short control link and a short control cycle, resulting in better anti-skid control effectiveness and meeting anti-skid control requirements.

[0164] The above descriptions are only some embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A vehicle anti-skid control method, comprising: (S1) obtaining an actual rotation speed of a motor of the vehicle; (S21) obtaining the current speed of the vehicle; (S22) determining an actual slip rate of the vehicle according to the actual motor speed and the current vehicle speed; (S23) obtaining the actual utilized adhesion coefficient of the vehicle; (S24) determining an optimal slip ratio of the vehicle according to the actual slip ratio and the actually utilized adhesion coefficient; (S25) determining a target speed of a motor of the vehicle according to an optimal slip ratio of the vehicle; (S3) determining a slip state of the vehicle according to the actual speed of the motor and the target speed of the motor; and (S4) determining a current adjustment amount of the motor drive torque of the vehicle according to the slip state of the vehicle, and determining an adjusted motor drive torque according to the current adjustment amount so that the actual speed of the motor of the vehicle reaches the target speed of the motor.

2. The method according to claim 1, wherein: (S21) obtaining the current speed of the vehicle, including: (S211) obtaining the speed of the wheels of the vehicle, the acceleration of the vehicle body and the steering wheel angle; and (S212) Determine the current speed of the vehicle based on the speed of the vehicle's wheels, the acceleration of the vehicle body, and the steering wheel angle.

3. The method according to claim 1, wherein: (S22) determining an actual slip rate of the vehicle according to the actual motor speed and the current vehicle speed, including: (S221) Determine the actual slip rate of the vehicle based on the ratio of the actual rotational speed of the motor to the product of the current vehicle speed and the transmission ratio of the transmission system of the vehicle.

4. The method according to claim 1, wherein: (S23) obtaining the actual utilized adhesion coefficient of the vehicle, including: (S231) obtaining the current vertical load and longitudinal driving force of the vehicle; and (S232) Determine the actual utilized adhesion coefficient of the vehicle according to the ratio of the current longitudinal driving force of the vehicle to the vertical load.

5. The method according to claim 1, wherein: (S24) determining an optimal slip ratio of the vehicle according to the actual slip ratio and the actual utilized adhesion coefficient, including: (S241) determining whether the actual slip ratio is greater than a slip ratio threshold; If the actual slip rate is less than the slip rate threshold, determining the actual slip rate as an optimal slip rate of the vehicle; If the actual slip rate is greater than the slip rate threshold, by comparing the actual slip rate and the actual utilized adhesion coefficient with pre-stored standard slip rates and standard utilized adhesion coefficients of multiple standard road surfaces, respectively determining a plurality of weight coefficients of the current road surface relative to the multiple standard road surfaces; and (S242) Determine the optimal slip ratio of the vehicle based on a plurality of weight coefficients of the current road surface relative to the plurality of standard road surfaces.

6. The method according to claim 5, wherein: (S242) determining the optimal slip rate of the vehicle according to a plurality of weight coefficients of the current road surface relative to the plurality of standard road surfaces, including: The optimal slip rate of the vehicle is determined as the ratio of the sum of the products of the standard slip rate of each standard road surface and its corresponding weight coefficient to the sum of multiple weight coefficients of the current road surface relative to the multiple standard road surfaces.

7. The method according to claim 1, wherein: (S25) determining a target speed of a motor of the vehicle according to the optimal slip ratio of the vehicle, including: (S251) Determine a target speed of the motor of the vehicle according to the current vehicle speed, the transmission ratio of the transmission system of the vehicle and the optimal slip ratio.

8. The method according to claim 7, wherein: Determining a target speed of a motor of the vehicle further includes: (S26) determining a correction amount of the motor target speed according to the product of the rate of change of the motor drive torque of the vehicle and the deformation coefficient of the transmission system of the vehicle; and (S27) The motor target speed is corrected according to the correction amount of the motor target speed to determine the corrected motor target speed as the motor target speed of the vehicle.

9. The method according to claim 1, wherein: (S3) determining the slip state of the vehicle according to the actual speed of the motor and the target speed of the motor, including: (S31) determining a motor speed deviation value of the vehicle according to the motor target speed of the vehicle and the motor actual speed; (S32) determining a rate of change of the motor speed deviation value according to the motor speed deviation value; (S33) Determine the slip state of the vehicle based on the motor speed deviation value and the rate of change of the motor speed deviation value.

10. The method according to claim 9, wherein: Determining the slip state of the vehicle according to the motor speed deviation value and the motor speed deviation value change rate includes one of the following: When the motor speed deviation value is greater than 0 and the motor speed deviation value change rate is greater than or equal to 0, determining that the slip state is an aggravated slip state; When the motor speed deviation value is greater than 0 and the motor speed deviation value change rate is less than 0, determining that the slip state is a slip callback state; When the motor speed deviation value is less than 0 and the motor speed deviation value change rate is greater than 0, determining that the slip state is a slip rising state; When the motor speed deviation value is less than 0 and the motor speed deviation value change rate is greater than or equal to 0, determining that the slip state is a slip aggravation state; or When the motor speed deviation value is equal to 0 and the motor speed deviation value change rate is an arbitrary value, it is determined that the slip state is the optimal slip state.

11. The method according to claim 1 or 10, wherein: Determining a current adjustment amount of a motor drive torque of the vehicle according to a slip state of the vehicle, and making the actual speed of the motor of the vehicle reach the target speed of the motor by determining the adjusted motor drive torque according to the current adjustment amount, including: (S41) determining a current adjustment amount of a motor drive torque for the vehicle according to a slip state of the vehicle; (S42) determining the minimum value of the sum of the motor request torque of the vehicle, the current adjustment amount, and the motor request torque as the adjusted motor drive torque; and (S43) According to the adjusted motor driving torque, the actual motor speed of the vehicle is adjusted to reach the motor target speed.

12. The method according to claim 1 or 10, wherein: When the vehicle switches between different slip states, the method further includes: An initial switching value of the motor drive torque when the motor of the vehicle switches between different slip states is configured.

13. The method according to claim 12, wherein: Configuring the switching initial value of the motor driving torque when the motor of the vehicle switches between the different slip states includes: The switching initial value of the motor driving torque is determined according to the adjusted motor driving torque at a previous moment during the switching, the motor request torque during the switching, and the motor speed deviation value during the switching.

14. A computer-readable storage medium having a program stored thereon, wherein when the program is executed by a processor, the method according to any one of claims 1 to 13 is implemented.

15. A vehicle anti-skid control system, comprising: One or more processors, configured to implement the method according to any one of claims 1 to 13.

16. A vehicle comprising: The vehicle anti-skid control system as claimed in claim 15.

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