Vehicle stability control method, electronic device, storage medium and program product

Abstract

The present application provides a vehicle stability control method, electronic device, storage medium and program product, the method comprising: calculating the nominal state of the vehicle to obtain the ideal yaw rate of the vehicle; comparing the actual yaw rate with the ideal yaw rate to obtain different first steering conditions; based on the first steering condition and the vehicle stability phase diagram constraint, dividing the vehicle stability state into multiple second steering conditions, and adopting corresponding body stability control strategies under different second steering conditions. The present application clearly divides the second steering condition in which the steer-by-wire system and the body electronic stability system work, and executes appropriate body stability control strategies according to the dynamic characteristics of the vehicle under the second steering condition. Only when the steer-by-wire system cannot meet the stability control requirements will it enter the coordinated control of the steer-by-wire system and the body electronic stability system or the separate control state of the body electronic stability system, which effectively improves the stability and safety of vehicle driving.

Description

Technical Field

[0001] The present application relates to the technical field of wire-controlled steering control, and in particular to a vehicle stability control method, electronic equipment, storage medium and program product. Background Art

[0002] As an advanced automotive steering technology, the steer-by-wire (SBW) system has indeed brought revolutionary changes to vehicle handling and stability. It transmits the driver's steering intention to the wheels through electronic signals rather than traditional mechanical connections, thereby achieving precise and rapid control of the front wheel angle. The core advantage of this technology is that it can actively and flexibly adjust the front wheel angle to cope with various complex driving scenarios, especially in non-steady-state conditions, such as emergency obstacle avoidance, crosswind influence during high-speed driving, or driving on uneven roads. The advantages of the steer-by-wire system are particularly obvious.

[0003] The ESP (Electronic Stability Program) system, also known as the electronic stability system, is a mature system in the automotive field. As an advanced active safety technology, it generates additional yaw torque by applying braking force on different wheels, thus significantly improving the stability of the vehicle.

[0004] Although both the SBW system and the ESP system are dedicated to improving the lateral stability of the vehicle, there are indeed differences in their working principles and how they respond to extreme situations. When the SBW system can no longer provide additional lateral force, that is, the active front wheel steering angle can no longer generate additional tire lateral force to improve the body posture, the ESP system will generate an additional yaw moment by acting on the longitudinal braking force on different wheels. However, when ESP intervenes, in order to quickly stabilize the vehicle, the vehicle speed will be reduced rapidly. This sudden change in speed may make the driver feel uncomfortable or even pose a danger to surrounding vehicles. Moreover, the application of this braking force may cause the tires to have excessive longitudinal slip, especially on roads with low adhesion coefficients (such as wet roads). If the slip rate is too high, the vehicle may lose control and even skid or roll.

[0005] Due to the different control methods of the two, they will produce complex coupling and mutual influence when working at the same time. In order to give full play to the advantages of both and avoid potential conflicts, it is necessary to reasonably define their working ranges and design effective vehicle stability control methods. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present application provides a vehicle stability control method, electronic device, storage medium and program product, aiming to solve the problems of vehicle stability control confusion or poor control effect in the prior art.

[0007] In order to achieve the above purpose and other advantages, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present application provides a vehicle stability control method, comprising:

[0009] Calculate the nominal state of the vehicle and obtain the ideal yaw rate of the vehicle;

[0010] Comparing the actual yaw angular velocity of the vehicle with the ideal yaw angular velocity to obtain different first steering conditions;

[0011] Based on the first steering condition and the vehicle stability phase diagram constraint, the vehicle stable state is divided into a plurality of second steering conditions, and corresponding vehicle body stability control strategies are adopted under different second steering conditions.

[0012] According to a vehicle stability control method provided by the present application, the step of comparing the actual yaw angular velocity of the vehicle with the ideal yaw angular velocity to obtain different first steering conditions includes:

[0013] When the actual yaw rate is less than the ideal yaw rate, it is determined that the vehicle is in an understeering condition;

[0014] When the actual yaw rate is greater than the ideal yaw rate, it is determined that the vehicle is in an oversteering condition.

[0015] According to a vehicle stability control method provided by the present application, the plurality of the second steering conditions include: a steady-state understeering condition, a critical unstable understeering condition, an unstable understeering condition, a steady-state oversteering condition and an unstable oversteering condition;

[0016] The step of dividing the vehicle stable state into a plurality of second steering conditions based on the first steering condition and the vehicle stability phase diagram constraint comprises:

[0017] Determine the speed range required for analysis;

[0018] Under the preset road adhesion coefficient conditions, the vehicle stability phase diagram is drawn according to the sideslip angle of the center of mass;

[0019] Based on the vehicle stability phase diagram, it is determined whether the vehicle state can converge to the origin under different initial conditions, and the stability region restriction conditions of the vehicle are determined:

[0020]

[0021] In the formula, is the sideslip angle of the center of mass, is the first-order derivative of the sideslip angle at the center of mass, The first influencing factor related to the road adhesion coefficient, It is the second influencing factor related to both the road adhesion coefficient and the braking force;

[0022] The second influencing factor is adjusted by a preset empirical coefficient to divide the stability region restriction condition into a first stability sub-region restriction condition and a second stability sub-region restriction condition in adjacent intervals, and the vehicle stability state under the first stability sub-region restriction condition is higher than the vehicle stability state under the second stability sub-region restriction condition;

[0023] When the vehicle is in an understeering condition and satisfies the first stability sub-region restriction condition, the second steering condition is a steady-state understeering condition;

[0024] When the vehicle is in an understeering condition and satisfies the second stability sub-region restriction condition, the second steering condition is a critical instability understeering condition;

[0025] When the vehicle is in an understeering condition and does not meet the stability region restriction condition, the second steering condition is an unstable understeering condition;

[0026] When the vehicle is in an oversteering condition and satisfies the stability region restriction condition, the second steering condition is a steady-state oversteering condition;

[0027] When the vehicle is in an oversteering condition and does not meet the stability zone restriction condition, the second steering condition is an unstable oversteering condition.

[0028] According to a vehicle stability control method provided by the present application, the step of adopting corresponding vehicle body stability control strategies under different second steering conditions includes:

[0029] Under the steady-state understeer condition, a steer-by-wire system is used as a vehicle body stability control strategy;

[0030] Under the critical instability understeer condition, the steer-by-wire system and the vehicle stability system are used to work in coordination as a vehicle stability control strategy;

[0031] Under the unstable understeer condition, a vehicle body stability system is used as a vehicle body stability control strategy;

[0032] In the above steady oversteering condition, no additional vehicle stability control is performed;

[0033] Under the unstable oversteering condition, a vehicle body stability system is used as a vehicle body stability control strategy.

[0034] According to a vehicle stability control method provided by the present application, the step of using a steer-by-wire system as a vehicle body stability control strategy under the steady-state understeer condition includes:

[0035] Construct the two-degree-of-freedom dynamic equation of the vehicle without the additional yaw moment involved in the calculation;

[0036] Constructing a state space equation and discretizing the state space equation;

[0037] The vehicle's center of mass sideslip angle and yaw rate are made to approach an ideal state, and the front wheel steering angle compensation value required under the steady-state understeer condition is calculated by solving the discretized state space equation.

[0038] According to a vehicle stability control method provided by the present application, the step of using a steer-by-wire system and a vehicle body stability system to work in coordination as a vehicle body stability control strategy under the critical instability understeer condition includes:

[0039] Construct the two-degree-of-freedom dynamic equation of the vehicle with additional yaw moment involved in the calculation;

[0040] Constructing a state space equation and discretizing the state space equation;

[0041] The feedforward control input is designed so that the vehicle's center of mass sideslip angle and yaw rate approach ideal state values, and the front wheel steering angle compensation value required under the critical instability understeering condition is calculated by solving the discretized state space equation.

[0042] According to a vehicle stability control method provided by the present application, the step of calculating the nominal state of the vehicle to obtain the ideal yaw rate of the vehicle includes:

[0043] Real-time monitoring of vehicle driving status parameters;

[0044] Based on the driving state parameters and a preset vehicle stability factor, a first yaw angular velocity of the vehicle in a steady state is calculated using a steady-state vehicle two-degree-of-freedom model;

[0045] Determining an ideal maximum yaw rate based on the driving state parameter and the road adhesion coefficient;

[0046] The ideal yaw rate is obtained based on the first yaw rate and the ideal yaw rate maximum value.

[0047] In a second aspect, the present application provides an electronic device, the electronic device comprising:

[0048] One or more processors; and a memory storing computer program instructions, which, when executed, cause the processor to perform any of the vehicle stability control methods described above.

[0049] In a third aspect, the present application provides a computer-readable storage medium having a computer program / instruction stored thereon, wherein the computer program / instruction, when executed by a processor, implements any of the vehicle stability control methods described above.

[0050] In a fourth aspect, the present application provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements any of the vehicle stability control methods described above.

[0051] The present application provides a vehicle stability control method, electronic device, storage medium and program product, which obtains the ideal yaw rate of the vehicle by calculating the nominal state of the vehicle; compares the actual yaw rate of the vehicle with the ideal yaw rate to obtain different first steering conditions; divides the vehicle stability state into multiple second steering conditions based on the first steering condition and the vehicle stability phase diagram constraint, and adopts corresponding body stability control strategies under different second steering conditions. The present application clearly divides the second steering conditions in which the steer-by-wire system and the body electronic stability system work, and executes appropriate body stability control strategies according to the dynamic characteristics of the vehicle under different second steering conditions. To prevent the sudden braking intervention of the body electronic stability system from making the driver feel uncomfortable, the steer-by-wire system and the body electronic stability system are coordinated or the body electronic stability system is controlled alone only when the steer-by-wire system cannot meet the stability control requirements, which effectively improves the stability and safety of the vehicle and prevents the occurrence of dangerous vehicle conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other implementation methods can be obtained based on these drawings without paying any creative work.

[0053] Figure 1 is a flow chart of a vehicle stability control method provided by the present application and provided in an embodiment of the present application;

[0054] Figure 2 is a schematic diagram of a stable region determined based on a vehicle stability phase diagram provided in an embodiment of the present application;

[0055] Figure 3 is a logic diagram of a vehicle steering control system provided by an embodiment of the present application;

[0056] Figure 4 It is a structural schematic diagram of the electronic device provided by this application. DETAILED DESCRIPTION

[0057] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specifically cites the preferred embodiments and describes them in detail with the accompanying drawings.

[0058] It should be noted that it is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict. Unless otherwise defined, the technical terms or scientific terms involved in this application should be the usual meanings understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation and may represent the singular or plural. The terms "including", "comprising", "having" and any of their variations involved in this application are intended to cover non-exclusive inclusions; the terms "first", "second", "third", etc. involved in this application are merely to distinguish similar objects and do not represent a specific ordering of objects.

[0059] Reference Figure 1 As shown, the embodiment of the present application provides a vehicle stability cooperative control method, including:

[0060] Step S1: Calculate the nominal state of the vehicle to obtain the ideal yaw rate of the vehicle.

[0061] In this embodiment, step S1 specifically includes:

[0062] Step S101: real-time monitoring of vehicle driving state parameters;

[0063] Step S102: Based on the driving state parameters and the preset vehicle stability factor, a first yaw rate of the vehicle in a steady state is calculated using a steady-state vehicle two-degree-of-freedom model;

[0064] Step S103: determining the maximum ideal yaw rate based on the driving state parameters and the road adhesion coefficient;

[0065] Step S104: obtaining an ideal yaw rate based on the first yaw rate and the maximum ideal yaw rate.

[0066] Specifically, the vehicle driving state parameters include basic driving parameters, vehicle dynamics parameters and tire state parameters, etc. Basic driving parameters include: longitudinal speed (i.e., the forward speed of the vehicle), lateral speed (i.e., the speed component of the vehicle perpendicular to the forward direction), lateral acceleration, etc. Vehicle dynamics parameters include: yaw rate, center of mass sideslip angle, etc. Tire state parameters include: tire sideslip angle, tire lateral force, front wheel cornering stiffness, rear wheel cornering stiffness, etc.

[0067] During vehicle driving, some driving state parameters can be monitored and obtained in real time through various sensors installed on the vehicle (such as wheel speed sensor, steering angle sensor, lateral acceleration sensor, etc.), such as vehicle speed, steering angle, lateral acceleration, yaw rate, etc. There are also some driving state parameters that cannot be measured directly by sensors due to technical limitations or cost considerations, such as the sideslip angle of the center of mass, which usually cannot be measured directly by sensors, but can be calculated by combining the data of other sensors with the vehicle dynamics model.

[0068] The two-degree-of-freedom model of a steady-state vehicle is shown in formula (1):

[0069] (1)

[0070] in, is the vehicle mass, is the longitudinal velocity, is the sideslip angle of the center of mass, is the yaw angular velocity, is the front wheel cornering stiffness, is the rear wheel cornering stiffness, is the distance from the vehicle's center of mass to the front axle, is the distance from the vehicle's center of mass to the rear axle, is the moment of inertia, Turn the corner for the driver, is the gear ratio of the steer-by-wire system.

[0071] make , the first yaw rate of the vehicle in steady state is obtained, as shown in formula (2):

[0072] (2)

[0073] in, is the first yaw angular velocity, is the vehicle wheelbase,

[0074] 𝐾 is the vehicle stability factor,

[0075] Due to the limitation of road adhesion coefficient, the maximum value of ideal yaw rate is limited, as shown in formula (3):

[0076] (3)

[0077] in, is the ideal maximum yaw rate, is the acceleration due to gravity, is the road adhesion coefficient.

[0078] The ideal yaw rate of the vehicle is calculated by formula (4):

[0079] (4)

[0080] in, is the ideal yaw rate, is a symbolic function.

[0081] For formula (1), let , we can also get the first center of mass sideslip angle, as shown in formula (5):

[0082] (5)

[0083] in, is the first center of mass sideslip angle.

[0084] Due to the limitation of road adhesion coefficient, the maximum value of the ideal center of mass sideslip angle is limited, as shown in formula (6):

[0085] (6)

[0086] The ideal center of mass sideslip angle of the vehicle is calculated by formula (7):

[0087] (7)

[0088] Step S2: Compare the actual yaw angular velocity of the vehicle with the ideal yaw angular velocity to obtain different first steering conditions.

[0089] In this embodiment, step S2 specifically includes:

[0090] Step S201: when the actual yaw rate is less than the ideal yaw rate, it is determined that the vehicle is in an understeering condition;

[0091] Step S202: When the actual yaw rate is greater than the ideal yaw rate, it is determined that the vehicle is in an oversteering condition.

[0092] Specifically, the first steering condition includes an understeering condition and an oversteering condition. When the actual yaw rate is less than the ideal yaw rate, that is, , the vehicle is in an understeering condition, and the additional yaw torque of the vehicle can be changed by changing the tire lateral force; when the actual yaw rate of the vehicle is greater than the ideal yaw rate, that is, , the vehicle is in oversteering condition, due to the ideal yaw rate The lateral road adhesion coefficient limitation term is included, indicating that the lateral tire force of the vehicle has reached saturation and the vehicle stability can no longer be improved by generating additional yaw torque by changing the lateral force of the wheel.

[0093] Step S3: Based on the first steering condition and the vehicle stability phase diagram constraint, the vehicle stable state is divided into a plurality of second steering conditions, and corresponding vehicle body stability control strategies are adopted under different second steering conditions.

[0094] In this embodiment, in step S3, the step of dividing the vehicle stable state into a plurality of second steering conditions based on the first steering condition and the vehicle stability phase diagram constraint includes:

[0095] Step S301: determining the vehicle speed range required for analysis;

[0096] Step S302: Under a preset road adhesion coefficient condition, a vehicle stability phase diagram is drawn according to the center of mass sideslip angle;

[0097] Step S303: Based on the vehicle stability phase diagram, determine whether the vehicle state can converge to the origin under different initial conditions, and determine the vehicle stability region restriction condition as follows:

[0098]

[0099] In the formula, is the sideslip angle of the center of mass, is the first-order derivative of the sideslip angle at the center of mass, The first influencing factor related to the road adhesion coefficient, It is the second influencing factor related to both road adhesion coefficient and braking force.

[0100] Specifically, in MATLAB, the vehicle speeds of the vehicles in different ranges are plotted. The stability phase diagram, that is, the center of mass slip angle-center of mass slip angular velocity phase diagram, such as Figure 2 As shown in the figure, a stability phase diagram is provided when the vehicle is in an intermediate speed range (such as a speed of 60km / h) and is drawn based on a road adhesion coefficient of 0.8. The divergent curve in the phase diagram indicates that the system is unstable in this state and the vehicle is very likely to become unstable. The curve that converges to the origin indicates that the initial state eventually tends to be stable. The horizontal axis in the phase diagram represents the sideslip angle of the center of mass , the vertical axis represents the center of mass sideslip angular velocity MATLAB can also be used to draw other speed intervals (slow speed interval: such as the interval where the speed does not exceed the first speed threshold, high speed interval: the interval where the speed is higher than the second speed threshold, and the interval between the first speed threshold and the second speed threshold is the intermediate speed interval), and vehicles under the influence of other road adhesion coefficients. Stability phase diagram. The stable region of the phase plane is a quadrilateral closed by a dotted line. The first influencing factor is obtained by calculating the slope of the curve in this stable region. , which is related to the road adhesion coefficient, and the intercept of the calculated curve is the second influencing factor , which is related to both the road adhesion coefficient and the braking force. Therefore, the first influencing factor in different vehicle speed ranges can be calculated and the second impact factor .

[0101] The plurality of second steering conditions include: steady-state understeering condition, critical instability understeering condition, instability understeering condition, steady-state oversteering condition and instability oversteering condition. The specific classification is as follows:

[0102] The second influencing factor is determined by the preset empirical coefficient A. Adjustment is made to divide the stability region constraints into first stability sub-region constraints of adjacent intervals and the second stability sub-region constraint , the vehicle stability state under the first stability sub-region restriction condition is higher than the vehicle stability state under the second stability sub-region restriction condition.

[0103] The empirical coefficient A is less than 1 and is usually set to 0.8. It can also be adjusted according to actual conditions.

[0104] Therefore, by introducing the empirical coefficient A, the second influencing factor Adjustments are made to make a more flexible secondary division of the stability area. In the first stability sub-area, due to the higher requirements for vehicle stability, the control system can adopt a more active control strategy to ensure the stability of the vehicle; while in the second stability sub-area, the control requirements can be appropriately relaxed to balance stability with driving comfort or power.

[0105] When the vehicle is in understeer condition And satisfy the first stability sub-region restriction condition In this case, the second steering condition is a steady-state understeering condition.

[0106] When the vehicle is in understeer condition And satisfy the second stability sub-region restriction condition , the second steering condition is a critical instability understeering condition.

[0107] When the vehicle is in understeer condition And does not meet the stability region restriction conditions In this case, the second steering condition is an unstable understeering condition.

[0108] When the vehicle is in oversteering condition And satisfy the stability region restriction condition In this case, the second steering condition is a steady-state oversteering condition.

[0109] When the vehicle is in oversteering condition And does not meet the stability region restriction conditions In this case, the second steering condition is an unstable oversteering condition.

[0110] In this embodiment, in step S3, the step of adopting corresponding vehicle body stability control strategies under different second steering conditions includes:

[0111] In steady-state understeer conditions, the steer-by-wire system is used as the vehicle body stability control strategy;

[0112] Under critical instability and understeer conditions, the steer-by-wire system and the vehicle stability system work together as the vehicle stability control strategy;

[0113] Under unstable understeer conditions, the vehicle body stability system is used as the vehicle body stability control strategy;

[0114] No additional vehicle stability control is performed under steady oversteer conditions;

[0115] Under unstable oversteering conditions, the body stability system is used as the body stability control strategy.

[0116] Specifically, since the SBW system eliminates the mechanical connection, an additional front wheel steering angle can be applied to improve vehicle stability before the ESP system intervenes. Therefore, the SBW system is used in steady-state understeer conditions because the vehicle is still stable as a whole and has not yet reached the edge of instability, although it has a tendency to understeer. The SBW system can accurately control the steering angle and speed, and by adjusting the steering in a timely manner, it can effectively prevent the vehicle from further entering an unstable state, thereby maintaining the stability of the vehicle.

[0117] In the critical instability understeer condition, the vehicle is close to the edge of instability (the tire lateral force is close to saturation), and the active front wheel steering angle of the SBW system can no longer generate additional tire lateral force to improve the body posture. Therefore, relying solely on the control of the SBW system may not be enough to completely avoid instability. At this time, the assistance of the ESP system is needed. The ESP system can provide additional stability support through braking intervention and other means, and work together with the SBW system to more effectively prevent vehicle instability and ensure driving safety.

[0118] Through the above-mentioned multiple second steering conditions divided according to different vehicle stability states, the separate working mode or cooperative working mode of the SBW system and the ESP system in different second steering conditions is obtained, as shown in Table 1, where the condition Used to exclude the vehicle from driving in a straight line.

[0119] Table 1 Body stability control strategies adopted in different second steering conditions

[0120]

[0121] In this embodiment, under the steady-state understeer condition, the steps of using the steer-by-wire system as the vehicle body stability control strategy include:

[0122] Construct the two-degree-of-freedom dynamic equation of the vehicle without the additional yaw moment involved in the calculation;

[0123] Construct state space equations and discretize them;

[0124] The vehicle's center of mass sideslip angle and yaw rate are made to approach the ideal state, and the front wheel steering angle compensation value required under steady-state understeer conditions is calculated by solving the discretized state space equation.

[0125] Alternatively, under the critical instability understeer condition, the steps of using the steer-by-wire system and the vehicle stability system to work together as the vehicle stability control strategy include:

[0126] Construct the two-degree-of-freedom dynamic equation of the vehicle with additional yaw moment involved in the calculation;

[0127] Construct state space equations and discretize them;

[0128] The feedforward control input is designed to make the vehicle's sideslip angle and yaw rate approach the ideal state values, and the front wheel angle compensation value required under the critical instability understeering condition is calculated by solving the discretized state space equation.

[0129] Specifically, the front wheel steering angle compensation value is calculated by the following method:

[0130] Construct and calculate the front wheel angle compensation value The two-degree-of-freedom dynamic equation of the vehicle is shown in formula (8):

[0131] (8)

[0132] in, is the vehicle mass, is the longitudinal velocity, is the sideslip angle of the center of mass, is the yaw angular velocity, is the front wheel cornering stiffness, is the rear wheel cornering stiffness, is the distance from the vehicle's center of mass to the front axle, is the distance from the vehicle's center of mass to the rear axle, is the moment of inertia, is the front wheel steering angle compensation value, is the additional yaw torque.

[0133] In order to further analyze and calculate the sideslip angle and yaw rate of the center of mass, equation (8) is converted into equation (9):

[0134] (9)

[0135] make , the state space equation is established as shown in formula (10):

[0136] (10)

[0137] in,

[0138] Discretize equation (10) to get equation (11):

[0139] (11)

[0140] in, , . is the unit matrix, which represents the part used to keep the state variables unchanged during the discretization process. is the sampling time matrix, which reflects the influence of the time interval on the system state change during the discretization process.

[0141] The following formula is used to make the vehicle's center of mass sideslip angle and yaw rate approach the ideal state:

[0142]

[0143] The error between the actual value and the ideal value of the sideslip angle and yaw rate based on the center of mass , the state space equation is , ,in, represents the control gain, which determines The change in output The proportional relationship between them.

[0144] It should be noted that when the SBW system is controlled alone, The value of is 0. When the SBW system and the ESP system work together, the additional yaw torque generated by the ESP system There is a certain value, at this time and Cannot be 0 at the same time, the state space equation is transformed into , so it is necessary to design a feedforward control input , so that each item of error 𝑒 approaches 0, specifically: . is 0, specifically: The front wheel steering angle compensation value is .

[0145] like Figure 3 As shown, the front wheel angle compensation value Output the front wheel steering angle to the driver Compensation is performed to obtain the ideal front wheel steering angle under the corresponding working conditions, and then input into the wire control steering execution system for execution. , is the steering wheel angle, is the steer-by-wire gear ratio.

[0146] When the vehicle is in an unstable understeer state, it means that the vehicle has lost stability, that is, the vehicle cannot steer according to the driver's intention and there is a risk of deviating from the predetermined trajectory. At this time, the ESP system can quickly identify the unstable state of the vehicle by monitoring the vehicle's driving status in real time. Subsequently, the ESP system will intervene in the braking of the wheels, adjust the vehicle's driving direction and speed, thereby restoring the stability of the vehicle and preventing the vehicle from losing control.

[0147] Similarly, in the case of unstable oversteering, the vehicle will also show an unstable state, but this is oversteering, that is, the vehicle oversteers and there is a risk of rollover. The ESP system can also play an important role, through brake intervention and engine management, timely adjust the steering angle and speed of the vehicle to prevent further instability of the vehicle and ensure driving safety.

[0148] Therefore, under the condition of insufficient instability or oversteering, the use of ESP control can quickly respond and correct the vehicle's driving state, thereby preventing accidents to the greatest extent and ensuring driving safety.

[0149] In summary, a vehicle stability control method provided by an embodiment of the present application obtains an ideal yaw rate of the vehicle by calculating the nominal state of the vehicle; compares the actual yaw rate of the vehicle with the ideal yaw rate to obtain different first steering conditions; based on the first steering condition and the vehicle stability phase diagram constraint, the vehicle stability state is divided into multiple second steering conditions, and corresponding body stability control strategies are adopted under different second steering conditions. The present application clearly divides the second steering conditions in which the steer-by-wire system and the body electronic stability system work, and executes appropriate body stability control strategies according to the dynamic characteristics of the vehicle under different second steering conditions. To prevent the sudden braking intervention of the body electronic stability system from making the driver feel uncomfortable, the steer-by-wire system and the body electronic stability system are coordinated or the body electronic stability system is controlled alone only when the steer-by-wire system cannot meet the stability control requirements. This effectively improves the stability and safety of the vehicle and prevents the occurrence of dangerous vehicle conditions.

[0150] Those skilled in the art will appreciate that, in the above method of specific implementation, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of the steps should be determined by their functions and possible internal logic.

[0151] In addition, some embodiments of the present application also provide an electronic device. The electronic device may be a digital computer in various forms, such as a laptop computer, a desktop computer, a workbench, a personal digital assistant, a server, a blade server, a mainframe computer, etc. The electronic device may also be a mobile device in various forms, such as a personal digital processing, a cellular phone, a smart phone, a wearable device, and other similar computing devices.

[0152] The electronic device includes: one or more processors; and a memory storing computer program instructions, wherein when the computer program instructions are executed, the processor executes the steps of the vehicle stability control method provided in any one or more of the above embodiments. Figure 4 An exemplary structural diagram of the electronic device is disclosed. Figure 4As shown, the electronic device includes: one or more processors 1101, a memory 1102, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed in the electronic device, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some other embodiments, if necessary, multiple processors and / or multiple buses can be used with multiple memories and multiple memories. Similarly, multiple electronic devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Among them, the components shown in this article, their connections and relationships, and their functions are only examples, and are not intended to limit the implementation of the present application described and / or required herein.

[0153] The electronic device may further include: an input device 1103 and an output device 1104. The processor 1101, the memory 1102, the input device 1103 and the output device 1104 may be connected via a bus or other means. Figure 4 The example of connecting through bus is taken in the following.

[0154] The input device 1103 can receive input digital or character information, and generate key signal input related to the user settings and function control of the electronic device, such as a touch screen, a keypad, a mouse, a track pad, a touch pad, an indicator rod, one or more mouse buttons, a trackball, a joystick and other input devices. The output device 1104 may include a display device, an auxiliary lighting device (e.g., LED, Light-Emitting Diode, light-emitting diode) and a tactile feedback device (e.g., a vibration motor), etc. The display device may include, but is not limited to, a liquid crystal display (LCD, Liquid Crystal Display), a light-emitting diode (LED) display and a plasma display. In some embodiments, the display device may be a touch screen.

[0155] To provide interaction with a user, the electronic device may be a computer. The computer has: a display device (e.g., a CRT (Cathode-Ray Tube) or LCD (Liquid Crystal Display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or a trackball), through which the user can provide input to the computer. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0156] In the embodiments of the present application, a computer program / instruction is stored on a computer-readable medium, and when the computer program / instruction is executed by a processor, the steps of the vehicle stability control method provided in any one or more of the above embodiments are implemented. The computer-readable medium may be included in the electronic device described in the above embodiments; or it may exist independently without being assembled into the device. The above computer-readable medium carries one or more computer-readable instructions.

[0157] The memory 1102 can be used as a non-transient computer-readable storage medium, which can be used to store non-transient software programs, non-transient computer executable programs and modules. The processor 1101 executes various functional applications and data processing of the server by running the non-transient software programs, instructions and modules stored in the memory 1102, so as to implement the program instructions / modules corresponding to the method provided by any one or more embodiments in the embodiments of the present application.

[0158] The memory 1102 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the electronic device, etc. In addition, the memory 1102 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory 1102 may optionally include a memory remotely arranged relative to the processor 1101, and these remote memories may be connected to the electronic device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0159] It should be noted that more specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0160] Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and can be implemented by any method or technology to store information. Information can be computer-readable instructions, data structures, modules of programs or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission medium that can be used to store information that can be accessed by a computing device.

[0161] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0162] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. For example, an application-specific integrated circuit (ASIC), a general-purpose computer or any other similar hardware device may be used for implementation. In some embodiments, the software program of the present application may be executed by a processor to implement the above steps or functions. Similarly, the software program of the present application (including related data structures) may be stored in a computer-readable recording medium, such as a RAM memory, a magnetic or optical drive or a floppy disk and the like. In addition, some steps or functions of the present application may be implemented by hardware, for example, as a circuit that cooperates with a processor to perform various steps or functions.

[0163] The computer program product provided in the embodiment of the present application includes one or more computer programs / instructions, which, when executed by the processor, generate in whole or in part the process or function described in the embodiment of the present application. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, a computer, a server, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL, Digital Subscriber Line)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server, or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state drive, solid state disk, SSD), etc.

[0164] The flow chart or block diagram in the accompanying drawings shows the possible architecture, function and operation of the equipment, method and computer program product according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented with a dedicated system for hardware that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0165] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily mention changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims, and the above embodiments should be regarded as exemplary and non-restrictive.

Claims

1. A vehicle stability control method, characterized in that: include: Calculate the nominal state of the vehicle and obtain the ideal yaw rate of the vehicle; Comparing the actual yaw angular velocity of the vehicle with the ideal yaw angular velocity to obtain different first steering conditions; Based on the first steering condition and the vehicle stability phase diagram constraint, the vehicle stability state is divided into a plurality of second steering conditions, and corresponding vehicle body stability control strategies are adopted under different second steering conditions; The second steering condition includes: a steady-state understeering condition, a critical unstable understeering condition, an unstable understeering condition, a steady-state oversteering condition and an unstable oversteering condition; The step of dividing the vehicle stable state into a plurality of second steering conditions based on the first steering condition and the vehicle stability phase diagram constraint comprises: Determine the speed range required for analysis; Under the preset road adhesion coefficient conditions, the vehicle stability phase diagram is drawn according to the sideslip angle of the center of mass; Based on the vehicle stability phase diagram, it is determined whether the vehicle state can converge to the origin under different initial conditions, and the stability region restriction conditions of the vehicle are determined: ； In the formula, is the sideslip angle of the center of mass, is the first-order derivative of the sideslip angle at the center of mass, The first influencing factor related to the road adhesion coefficient, It is the second influencing factor related to both the road adhesion coefficient and the braking force; The second influencing factor is adjusted by a preset empirical coefficient to divide the stability region restriction condition into a first stability sub-region restriction condition and a second stability sub-region restriction condition in adjacent intervals, and the vehicle stability state under the first stability sub-region restriction condition is higher than the vehicle stability state under the second stability sub-region restriction condition; When the vehicle is in an understeering condition and satisfies the first stability sub-region restriction condition, the second steering condition is a steady-state understeering condition; When the vehicle is in an understeering condition and satisfies the second stability sub-region restriction condition, the second steering condition is a critical instability understeering condition; When the vehicle is in an understeering condition and does not meet the stability region restriction condition, the second steering condition is an unstable understeering condition; When the vehicle is in an oversteering condition and satisfies the stability region restriction condition, the second steering condition is a steady-state oversteering condition; When the vehicle is in an oversteering condition and does not meet the stability region restriction condition, the second steering condition is an unstable oversteering condition; The step of adopting corresponding vehicle body stability control strategies under different second steering conditions includes: Under the steady-state understeer condition, a steer-by-wire system is used as a vehicle body stability control strategy; Under the critical instability understeer condition, the steer-by-wire system and the vehicle stability system are used to work in coordination as a vehicle stability control strategy; Under the unstable understeer condition, a vehicle body stability system is used as a vehicle body stability control strategy; In the above steady oversteering condition, no additional vehicle stability control is performed; Under the unstable oversteering condition, a vehicle body stability system is used as a vehicle body stability control strategy.

2. The vehicle stability control method according to claim 1, characterized in that: The step of comparing the actual yaw angular velocity of the vehicle with the ideal yaw angular velocity to obtain different first steering conditions includes: When the actual yaw rate is less than the ideal yaw rate, it is determined that the vehicle is in an understeering condition; When the actual yaw rate is greater than the ideal yaw rate, it is determined that the vehicle is in an oversteering condition.

3. The vehicle stability control method according to claim 1, characterized in that: The step of using a steer-by-wire system as a vehicle body stability control strategy under the steady-state understeer condition includes: Construct the two-degree-of-freedom dynamic equation of the vehicle without the additional yaw moment involved in the calculation; Constructing a state space equation and discretizing the state space equation; The vehicle's center of mass sideslip angle and yaw rate are made to approach an ideal state, and the front wheel steering angle compensation value required under the steady-state understeer condition is calculated by solving the discretized state space equation.

4. The vehicle stability control method according to claim 1, characterized in that: The step of using the steer-by-wire system and the vehicle body stability system to work in coordination as a vehicle body stability control strategy under the critical instability understeer condition includes: Construct the two-degree-of-freedom dynamic equation of the vehicle with additional yaw moment involved in the calculation; Constructing a state space equation and discretizing the state space equation; The feedforward control input is designed so that the vehicle's center of mass sideslip angle and yaw rate approach ideal state values, and the front wheel steering angle compensation value required under the critical instability understeering condition is calculated by solving the discretized state space equation.

5. The vehicle stability control method according to claim 1, characterized in that: The step of calculating the nominal state of the vehicle to obtain the ideal yaw rate of the vehicle includes: Real-time monitoring of vehicle driving status parameters; Based on the driving state parameters and a preset vehicle stability factor, a first yaw angular velocity of the vehicle in a steady state is calculated using a steady-state vehicle two-degree-of-freedom model; Determining an ideal maximum yaw rate based on the driving state parameter and the road adhesion coefficient; The ideal yaw rate is obtained based on the first yaw rate and the ideal yaw rate maximum value.

6. An electronic device, characterized in that: The electronic device comprises: One or more processors; and a memory storing computer program instructions, which, when executed, cause the processor to perform the vehicle stability control method as claimed in any one of claims 1 to 5.

7. A computer-readable storage medium having a computer program and / or instructions stored thereon, characterized in that: When the computer program and / or instructions are executed by a processor, the vehicle stability control method according to any one of claims 1 to 5 is implemented.

8. A computer program product comprising a computer program and / or instructions, characterized in that: When the computer program and / or the instruction is executed by the processor, the vehicle stability control method as claimed in any one of claims 1 to 5 is implemented.

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