Active front wheel steering control method, electronic device, storage medium and program product

Abstract

The present invention provides an active front wheel steering control method, electronic device, storage medium and program product. The front wheel steering angle is obtained by obtaining the driving speed and steering wheel angle of the vehicle during driving; based on the current road adhesion coefficient and the vehicle driving style, the first additional front wheel steering angle output by the active steering controller is constrained to obtain the second additional front wheel steering angle; based on the front wheel steering angle and the second additional front wheel steering angle, the ideal front wheel steering angle is obtained and input into the wire control steering actuator for execution. The present invention comprehensively considers the influence of the vehicle driving style and the road adhesion coefficient, and designs a dynamically adjusted active front wheel steering control strategy, so that the vehicle can steer according to the driver's control intention, while reducing the influence of external interference on the steering control. This ensures that the vehicle can maintain a stable driving state under different road conditions and driving styles, and provides a smoother and more natural steering response.

Description

Technical Field

[0001] The present invention relates to the technical field of wire-controlled steering, and in particular to an active front wheel steering control method, electronic equipment, storage medium and program product. Background Art

[0002] The steer-by-wire system abandons the mechanical connection between the steering wheel and the actuator, which makes the angular transmission and force transmission characteristics of the steering system not limited by the mechanical structure and can be freely designed according to the designer's wishes. At the same time, it can also be combined with vehicle dynamics control technology to complete the design of the steer-by-wire system control strategy to improve the active safety and handling stability of the car.

[0003] There will be disturbances in the active steering control of the steer-by-wire system. Disturbance usually refers to interference from the external environment (such as side wind, road environment, other vehicles passing by, etc.), measurement noise, system modeling errors, etc. In the existing active steering controller, a larger controller gain value is selected to suppress the impact of disturbances on the system. However, external disturbances do not always exist, but in order to suppress the disturbance, a larger controller gain has to be selected. A larger controller gain will cause the controller output to vibrate, affecting the control effect.

[0004] Therefore, how to design an active steering control strategy to make the active steering system more stable and reliable is an urgent problem to be solved in the current field of vehicle control technology. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides an active front-wheel steering control method, an electronic device, a storage medium and a program product, aiming to improve the anti-interference ability and robustness of the active steering control strategy, so as to ensure that the vehicle can maintain a stable driving state under different road conditions and driving styles, and provide a smoother and more natural steering response.

[0006] In order to achieve the above purpose and other advantages, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an active front wheel steering control method, comprising:

[0008] Obtain the driving speed and steering wheel angle of the vehicle during driving to obtain the front wheel angle;

[0009] Based on the current road adhesion coefficient and the vehicle driving style, constraining the first additional front wheel steering angle output by the active steering controller to obtain a second additional front wheel steering angle;

[0010] Based on the front wheel steering angle and the second additional front wheel steering angle, an ideal front wheel steering angle is obtained and input into a steer-by-wire actuator for execution.

[0011] According to an active front wheel steering control method provided by the present invention, the step of obtaining the vehicle speed and steering wheel angle during vehicle driving to obtain the front wheel angle includes:

[0012] Acquiring current state data of the vehicle, wherein the current state data includes: one or more of a driving speed, a yaw angular velocity, and a lateral acceleration;

[0013] Based on the driver's steering intention, generating the corresponding steering wheel angle;

[0014] obtaining a steer-by-wire transmission ratio based on the current driving speed, the steering wheel angle, the yaw rate and the lateral acceleration;

[0015] The steering wheel angle is converted into the front wheel angle based on the steer-by-wire transmission ratio.

[0016] According to an active front wheel steering control method provided by the present invention, the step of constraining a first additional front wheel steering angle output by an active steering controller based on a current road adhesion coefficient and a vehicle driving style to obtain a second additional front wheel steering angle comprises:

[0017] Get the current road adhesion coefficient;

[0018] Based on the driver's vehicle control, the current vehicle driving style is identified through a pre-trained driving style model;

[0019] Dynamically generate a corresponding weight coefficient according to different road adhesion coefficients and vehicle driving styles, and the weight coefficient is less than or equal to 1;

[0020] Based on the weight coefficient, the first additional front wheel turning angle is adjusted to obtain the second additional front wheel turning angle.

[0021] According to an active front wheel steering control method provided by the present invention, the step of dynamically generating corresponding weight coefficients according to different road adhesion coefficients and vehicle driving styles comprises:

[0022] Inputting the road adhesion coefficient and the weight coefficient into a regression equation generation model to establish a regression equation between the road adhesion coefficient and the weight coefficient;

[0023] quantifying the vehicle driving style to obtain a driving style quantization value;

[0024] The driving style quantification value is introduced into the regression equation, and the influence of the vehicle driving style on the weight coefficient is adjusted by the driving style quantification value.

[0025] According to an active front wheel steering control method provided by the present invention, the first additional front wheel steering angle output by the active steering controller is obtained by:

[0026] Estimate the center of mass slip angle based on the tire's cornering stiffness;

[0027] Construct a disturbance observer to estimate the system disturbance and calculate the disturbance estimate;

[0028] The disturbance estimation value, the center of mass sideslip angle and the active steering controller are combined, and a control amount of the active steering controller is determined as the first additional front wheel steering angle.

[0029] According to an active front wheel steering control method provided by the present invention, the step of estimating the center of mass sideslip angle based on the tire cornering stiffness comprises:

[0030] The linear relationship between tire lateral force and sideslip angle is established, and the expression of initial tire cornering stiffness is obtained;

[0031] Obtaining the front and rear axle slip angles of the vehicle in a steady state, and calculating the absolute value of the difference between the front and rear axle slip angles;

[0032] Substituting the absolute value into the expression of the initial tire cornering stiffness, the cornering stiffness of the tires on the front axle and the rear axle during the vehicle's driving process is obtained.

[0033] According to an active front wheel steering control method provided by the present invention, the step of constructing a disturbance observer to estimate the system disturbance and calculate the compensation value comprises:

[0034] Based on the front wheel steering angle and the cornering stiffness, a desired yaw rate and a desired center-of-mass slip angle are obtained by a vehicle dynamics model;

[0035] Based on the desired yaw rate and the desired center-of-mass sideslip angle, an observation error is defined, and a center-of-mass sideslip angle observer is constructed based on the observation error;

[0036] An intermediate variable is introduced to design a disturbance observer, and a disturbance observer for nonlinear disturbance observation is constructed based on the center of mass sideslip angle observer.

[0037] Based on the disturbance observer, a disturbance estimation value is obtained.

[0038] In a second aspect, the present invention provides an electronic device, the electronic device comprising:

[0039] One or more processors; and a memory storing computer program instructions, wherein when the computer program instructions are executed, the processor performs the steps of the active front wheel steering control method as described in any one of the above.

[0040] In a third aspect, the present invention provides a computer-readable storage medium having a computer program / instruction stored thereon, wherein the computer program / instruction, when executed by a processor, implements the steps of any of the active front wheel steering control methods described above.

[0041] In a fourth aspect, the present invention provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the steps of any of the active front wheel steering control methods described above.

[0042] The present invention provides an active front wheel steering control method, electronic device, storage medium and program product, which obtains the front wheel angle by acquiring the driving speed and steering wheel angle of the vehicle during driving; constrains the first additional front wheel angle output by the active steering controller based on the current road adhesion coefficient and the vehicle driving style to obtain the second additional front wheel angle; obtains the ideal front wheel angle based on the front wheel angle and the second additional front wheel angle, and inputs it into the wire control steering actuator for execution. The present invention comprehensively considers the influence of the vehicle driving style and the road adhesion coefficient, designs a dynamically adjusted active front wheel steering control strategy, constrains the first additional front wheel angle output by the active steering controller, and obtains a more reasonable second additional front wheel angle. The vehicle can be steered according to the driver's control intention, while reducing the influence of external interference on the steering control. This dynamically adjusted control strategy improves the anti-interference ability and robustness to ensure that the vehicle can maintain a stable driving state under different road conditions and driving styles, and provide a smoother and more natural steering response. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] 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.

[0044] Figure 1 is a flow chart of an active front wheel steering control method provided by an embodiment of the present invention;

[0045] Figure 2 is a line graph of the weight coefficient of active steering compensation affected by the road adhesion coefficient and the vehicle driving style provided by an embodiment of the present invention;

[0046] Figure 3 is a logic diagram of active steering system control provided by an embodiment of the present invention;

[0047] Figure 4 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0048] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, 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 invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows.

[0049] It should be noted that it is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present invention can be combined with other embodiments without conflict. Unless otherwise defined, the technical terms or scientific terms involved in the present invention should be the usual meanings understood by people with ordinary skills in the technical field to which the present invention belongs. The words "one", "a", "a", "the" and the like involved in the present invention 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 the present invention are intended to cover non-exclusive inclusions; the terms "first", "second", "third", etc. involved in the present invention are merely to distinguish similar objects and do not represent a specific ordering of objects.

[0050] The applicant has found that, currently, the lateral stability control of the active steering system is usually designed by considering the yaw rate and the sideslip angle of the center of mass. The vehicle's current desired yaw rate and sideslip angle are obtained based on the linear two-degree-of-freedom model of the vehicle, and the difference is made between the actual yaw rate and the sideslip angle of the center of mass. The additional front wheel turning angle is determined by the controller and executed by the steering motor, so that the wheels rotate to the corresponding angle to ensure stable driving of the vehicle.

[0051] Due to different road conditions (such as slippery, potholes, ramps and other complex road conditions) and different styles of driver's vehicle operation (such as steady driving, aggressive driving and other driving behaviors), the dynamic response of the vehicle during actual driving is quite different from the theoretical expectation based on the linear two-degree-of-freedom model of the vehicle. This difference causes the active steering system to rely only on yaw rate and center of mass sideslip angle for control, which may not be able to maintain optimal lateral stability under all working conditions. Therefore, designing a stable and reliable active steering control strategy is a complex and multifaceted issue, which requires comprehensive consideration of the influence of multiple factors. Based on this, the present invention provides an active front wheel steering control method, electronic equipment, storage medium and program product, which aims to improve the anti-interference ability and robustness of the active steering control strategy, so as to ensure that the vehicle can maintain a stable driving state under different road conditions and driving styles, and provide a smoother and more natural steering response.

[0052] Reference Figure 1 As shown, the present invention provides an active front wheel steering control method, comprising:

[0053] Step S1: Acquire the driving speed and steering wheel angle of the vehicle during driving to obtain the front wheel angle;

[0054] In this embodiment, step S1 specifically includes:

[0055] Step S101: obtaining current state data of the vehicle, the current state data including: one or more of driving speed, yaw angular velocity, and lateral acceleration;

[0056] Step S102: generating a corresponding steering wheel angle based on the driver's steering intention;

[0057] Step S103: obtaining a steering-by-wire transmission ratio based on the current driving speed, steering wheel angle, yaw rate and lateral acceleration;

[0058] Step S104: Convert the steering wheel angle into the front wheel angle based on the steer-by-wire transmission ratio.

[0059] Specifically, the driver expresses his steering intention by turning the steering wheel. The steering wheel angle directly reflects the degree of vehicle steering that the driver expects. The steering wheel angle sensor can measure the driver's steering angle and speed of the steering wheel in real time, thereby accurately reflecting the driver's steering intention. In some advanced driver assistance systems or autonomous driving systems, the driver's steering intention can also be predicted by analyzing factors such as the driver's driving behavior, vehicle status, and external environment, and the corresponding steering wheel angle command can be generated in advance. The current vehicle speed is also an important factor affecting the vehicle's steering characteristics. At different vehicle speeds, the vehicle's response to the steering wheel angle is different to ensure driving stability and safety.

[0060] The current state data of the vehicle is obtained through various sensors installed on the vehicle. The driving speed can be obtained through the vehicle speed sensor. The yaw rate and lateral acceleration can be measured by the inertial measurement unit (IMU) or a dedicated yaw rate and lateral acceleration sensor.

[0061] The steer-by-wire transmission ratio is based on a fixed yaw rate gain and / or a fixed lateral acceleration gain. The yaw rate gain is the ratio between the yaw rate and the steering wheel angle in a steady state, while the lateral acceleration gain is the ratio between the lateral acceleration and the steering wheel angle in a steady state. Therefore, the steer-by-wire transmission ratio is calculated by the variable transmission ratio module according to the steering wheel angle, driving speed, yaw rate and lateral acceleration. The corresponding front wheel angle command can be obtained by multiplying the steering wheel angle by the steer-by-wire transmission ratio. The front wheel angle obtained in this way can better meet the actual vehicle driving requirements, and can maintain the stable driving state of the vehicle under different vehicle speeds and working conditions, thereby improving the steering response speed and stability of the vehicle.

[0062] Step S2: Based on the current road adhesion coefficient and the vehicle driving style, constrain the first additional front wheel steering angle output by the active steering controller to obtain a second additional front wheel steering angle.

[0063] In this embodiment, step S2 specifically includes:

[0064] Step S201: Obtain the current road adhesion coefficient.

[0065] Specifically, the sensor detects the adhesion coefficient of the current road surface in real time. The adhesion coefficient refers to the ratio of the normal pressure of the wheel to the adhesion force, which reflects the friction between the tire and the road surface and has an important impact on the driving stability and handling performance of the vehicle.

[0066] Step S202: Based on the driver's vehicle control, the current vehicle driving style is identified through a pre-trained driving style model.

[0067] It should be noted that driving style refers to the personalized characteristics of the driver's vehicle during driving, such as aggressive, robust, conservative, etc. The driving data is processed using data analysis techniques (such as cluster analysis, neural networks, etc.) to identify the vehicle driving styles of different drivers. Therefore, this embodiment uses a neural network model to train a large amount of driving data and obtain a driving style model, which can identify the driver's driving style. In practical applications, the driver's vehicle control data (such as steering wheel angle, accelerator pedal position, brake pedal position, etc.) can be collected and input into a pre-trained driving style model for analysis. The road adhesion coefficient and vehicle driving style provide personalized steering control parameters for the subsequent active steering control algorithm.

[0068] Step S203: dynamically generate corresponding weight coefficients according to different road adhesion coefficients and vehicle driving styles, and the weight coefficient is less than or equal to 1.

[0069] In this embodiment, step S203 specifically includes:

[0070] Step S2031: inputting the road adhesion coefficient and the weight coefficient into the regression equation generation model to establish a regression equation between the road adhesion coefficient and the weight coefficient;

[0071] Step S2032: quantifying the vehicle driving style to obtain a driving style quantization value;

[0072] Step S2033: introducing the driving style quantification value into the regression equation, and adjusting the influence of the vehicle driving style on the weight coefficient by the driving style quantification value.

[0073] Step S204: adjusting the first additional front wheel turning angle based on the weight coefficient to obtain a second additional front wheel turning angle.

[0074] Specifically, the collected data is input into a regression equation generation model. This model can use linear regression, polynomial regression or other suitable regression methods to establish a mathematical relationship between the road adhesion coefficient and the weight coefficient. For example, a linear regression equation is used to design the road adhesion coefficient. x With weight coefficient y The relationship between.

[0075] The vehicle driving style is classified into categories, such as aggressive, steady, conservative, etc. A driving style quantitative value is assigned to each driving style. This quantitative value can be a numerical range, for example, a higher value corresponds to an aggressive style and a lower value corresponds to a conservative style.

[0076] The driving style quantification value is introduced into the regression equation. By adjusting the coefficient of the item related to the driving style quantification value in the regression equation, the influence of the driving style on the weight coefficient can be controlled. In this way, under different driving styles, the weight coefficient will be dynamically adjusted according to the road adhesion coefficient and driving style. The regression equation can be designed as the road adhesion coefficient x , Vehicle driving style z Associated with weight coefficient y The piecewise function is:

[0077] Driving style z For the robust type: when the road adhesion coefficient x In 0< x When ≤0.3, the weight coefficient y Keep it at 1 (i.e. 100% active steering compensation), which is not affected by driving style; and when 0.3< x When <0.8, as the road adhesion coefficient increases, the weight coefficient y Linear decrease; when x ≥0.8, the weight coefficient y Set it in a lower value range (such as 0.3, 0.25, 0.2, etc.), and use this fixed value to perform active steering compensation, such as Figure 2 shown.

[0078] Driving style z Aggressive type: In this case, the road adhesion coefficient is not taken into account or is less considered. x The weight coefficient y Set it within a higher value range (such as 0.8, 0.85, 0.9, etc.) for active steering compensation.

[0079] Driving style z For conservative type: weight coefficienty Consider the driving style quantification value z and weight coefficient α The weight coefficient y Set it in a medium value range (such as 0.45, 0.5, 0.55, etc.) for active steering compensation.

[0080] The above values ​​are only examples, and the actual values ​​can be obtained by fitting specific experimental data in the regression equation generation model.

[0081] After the weight coefficient is obtained, it can be applied to the adjustment of the first additional front wheel steering angle. y Multiply it by the first additional front wheel steering angle to obtain the adjusted second additional front wheel steering angle. y If the weight coefficient is less than 1, the second additional front wheel steering angle will be smaller than the first additional front wheel steering angle, thereby weakening the active steering control; if the weight coefficient is equal to 1, the second additional front wheel steering angle is equal to the first additional front wheel steering angle, indicating that the active steering control is not adjusted.

[0082] Reference Figure 3 As shown, in this embodiment, in step S2, the first additional front wheel steering angle output by the active steering controller Obtained through:

[0083] Step S201: estimating the center of mass slip angle based on the tire's cornering stiffness;

[0084] Step S202: construct a disturbance observer to estimate the system disturbance and calculate the disturbance estimation value;

[0085] Step S203: combining the disturbance estimation value, the center of mass sideslip angle and the active steering controller, and determining a control variable of the active steering controller as a first additional front wheel steering angle.

[0086] In this embodiment, step S201 specifically includes:

[0087] Step S2011: establishing a linear relationship between the tire lateral force and the sideslip angle, and obtaining an expression for the initial tire cornering stiffness;

[0088] Step S2012: Obtain the front and rear wheel slip angles of the vehicle in a steady state, and calculate the absolute value of the difference between the front and rear wheel slip angles;

[0089] Step S2013: Substitute the absolute value into the expression of the initial tire cornering stiffness to obtain the cornering stiffness of the front axle and rear axle tires during vehicle driving.

[0090] Specifically, tire cornering stiffness, as one of the important parameters of vehicle tire performance, has a great influence on vehicle dynamics and stability. If it can be accurately estimated, the effectiveness of active steering control of the vehicle can be greatly improved.

[0091] When the tire slip angle is small, the tire lateral force and the slip angle are linearly related as shown in formula (1):

[0092] (1)

[0093] in, is the lateral force on the front wheel, is the rear wheel lateral force, is the front wheel slip angle, is the rear wheel slip angle, , are proportional constants, representing the cornering stiffness of the front and rear tires respectively.

[0094] When the tire slip angle is approximately zero, the tire cornering stiffness can be expressed as formula (2):

[0095] (2)

[0096] In the formula, is the tire cornering stiffness; is the normalized cornering stiffness under different road adhesion coefficients; is the vertical force.

[0097] Combining equations (1) and (2) can give the expression of the initial tire cornering stiffness, as shown in equation (3):

[0098] (3)

[0099] in, is the normalized cornering stiffness under different road adhesion coefficients, is the road adhesion coefficient, The vertical force of the tire, The lateral force of the tire, is the ratio of the lateral force to the vertical force of the tire, is the tire slip angle.

[0100] For the center of mass slip angle which is difficult to obtain, the absolute value of the difference between the front and rear wheel slip angles during the vehicle's steady-state response is used as a substitute, as shown in formula (4):

[0101] (4)

[0102] in, is the front wheel slip angle, is the rear wheel slip angle, is the vehicle wheelbase, is the yaw angular velocity, is the longitudinal velocity of the vehicle along the direction of travel, , is the steering wheel angle, is the steer-by-wire gear ratio.

[0103] Substituting equation (4) into equation (3), the normalized tire cornering stiffness calculation formula for the left and right tires can be obtained as equation (5):

[0104] (5)

[0105] in, is the cornering stiffness of the front axle tire, is the cornering stiffness of the rear axle tire, is the front wheel slip angle, is the rear wheel slip angle, is the lateral force on the left front wheel, is the lateral force on the left rear wheel, is the lateral force on the right front wheel, is the lateral force on the right rear wheel.

[0106] In some embodiments, the recursive least square method may be used to calculate the cornering stiffness of the tire to improve the calculation accuracy.

[0107] In this embodiment, step S202 specifically includes:

[0108] Step S2021: based on the front wheel steering angle and the cornering stiffness, a desired yaw rate and a desired center-of-mass sideslip angle are obtained by a vehicle dynamics model;

[0109] Step S2022: defining an observation error based on the expected yaw rate and the expected center-of-mass sideslip angle, and constructing a center-of-mass sideslip angle observer based on the observation error;

[0110] Step S2023: introducing intermediate variables to design a disturbance observer, and constructing a disturbance observer for nonlinear disturbance observation based on the center of mass sideslip angle observer;

[0111] Step S2024: Based on the disturbance observer, obtain a disturbance estimation value.

[0112] Specifically, the vehicle dynamics model usually adopts a simplified vehicle dynamics model, such as a linear two-degree-of-freedom or three-degree-of-freedom model. Since the linear two-degree-of-freedom model is a simplified vehicle model, it has a certain model error compared with the actual vehicle model. Based on the front wheel angle and cornering stiffness, the yaw rate is obtained from the linear two-degree-of-freedom model. and the center of mass slip angle , the linear two-degree-of-freedom differential equation is shown in formula (6):

[0113] (6)

[0114] In the formula, is the cornering stiffness of the front and rear axles; is the sideslip angle of the center of mass; and is the distance from the center of mass to the front and rear axes; is the moment of inertia; is the front wheel turning angle, , is the steering wheel angle, The gear ratio for steer-by-wire; is the vehicle mass; is the longitudinal velocity; is the yaw angular velocity.

[0115] Considering the restriction of road adhesion coefficient on the ideal yaw rate and the ideal sideslip angle of center of mass, the yaw rate obtained based on the linear two-degree-of-freedom model is and the center of mass slip angle , the expected value of the yaw rate can be obtained by equations (7) and (8) respectively. and the expected value of the sideslip angle They are:

[0116] (7)

[0117] (8)

[0118] in, is the road adhesion coefficient, is the vehicle wheelbase, is a constant, is the acceleration due to gravity.

[0119] The difference between the ideal state parameters and the actual state parameters is taken as the observation error of the center of mass sideslip angle observer, as shown in formula (9):

[0120] (9)

[0121] in, is the actual yaw rate and the desired yaw rate The difference, is the estimated value of the center of mass sideslip angle Side slip angle with expected center of mass The difference.

[0122] To facilitate subsequent derivation, equation (6) is rewritten into state space form, as shown in equation (10):

[0123] (10)

[0124] in, ,

[0125] ,

[0126] .

[0127] Since the linear two-degree-of-freedom model is a simplified vehicle model, there is a certain model error between it and the actual vehicle model. The observation error is used as feedback to compensate. The designed center of mass sideslip angle observer is shown in formula (11):

[0128] (11)

[0129] in, is the estimated value of the yaw rate; is the estimated value of the sideslip angle of the center of mass; is the estimated value of lateral acceleration; is the observation error value of yaw angular velocity; is the observed error value of lateral acceleration; is the observer gain value, and The detailed description of is shown in formula (10).

[0130] Introducing intermediate variables Design the disturbance observer and define the disturbance observer Its derivative is shown in formula (12):

[0131] (12)

[0132] in, , is a constant, usually defined as 0.8, c is a constant and .

[0133] Substituting equation (9) and equation (12) into equation (11), we get equation (13):

[0134] (13)

[0135] in, , It is the sum of the uncertainty inside the system and the external disturbance, and its value is bounded; are all bounded variables, so Bounded.

[0136] At the same time, considering that the estimation error of the sideslip angle of the center of mass will affect the accuracy of the active steering lateral stability control, , assuming there is a positive constant satisfy , based on formula (11), a disturbance observer for nonlinear disturbance observation is constructed ,make , rewrite equation (13) into equation (14):

[0137] (14)

[0138] In the formula, , ,

[0139] , .

[0140] Estimating the disturbance in equation (14) yields equation (15):

[0141] (15)

[0142] in, is the estimated value of the total disturbance, is the internal state of the observer, is the observer gain and .

[0143] The disturbance estimate and the estimated value of the sideslip angle at the center of mass Combined with the active steering controller, the control amount of the active steering controller is determined, which is the first additional front wheel steering angle The calculation formula of the active steering controller is shown in formula (16):

[0144] (16)

[0145] In the formula, is the saturation function, and is a constant and .

[0146] The active steering control strategy based on disturbance compensation estimates the disturbance value through disturbance observation technology and compensates it to the active steering controller in a feedforward manner, so that the controller can suppress external disturbances in advance at a smaller controller gain, reducing the vibration of the system. As one of the important parameters of the vehicle, the cornering stiffness has an important impact on the vehicle's handling stability. The real-time calculated cornering stiffness can improve the observation accuracy of the center of mass sideslip angle. Therefore, the technology of disturbance observation combined with the center of mass sideslip angle compensation can effectively offset the disturbance and uncertainty in the system, making the active steering system more stable and reliable to improve the robustness of the system.

[0147] In summary, the present invention provides an active front wheel steering control method, which obtains the front wheel angle by obtaining the driving speed and steering wheel angle of the vehicle during driving; constrains the first additional front wheel angle output by the active steering controller based on the current road adhesion coefficient and the vehicle driving style to obtain the second additional front wheel angle; obtains the ideal front wheel angle based on the front wheel angle and the second additional front wheel angle, and inputs it into the wire control steering actuator for execution. The present invention comprehensively considers the influence of the vehicle driving style and the road adhesion coefficient, designs a dynamically adjusted active front wheel steering control strategy, constrains the first additional front wheel angle output by the active steering controller, and obtains a more reasonable second additional front wheel angle. The vehicle can steer according to the driver's control intention, while reducing the influence of external interference on the steering control. This dynamically adjusted control strategy improves the anti-interference ability and robustness to ensure that the vehicle can maintain a stable driving state under different road conditions and driving styles, and provide a smoother and more natural steering response.

[0148] 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.

[0149] 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.

[0150] 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 active front wheel steering 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.

[0151] 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.

[0152] 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., an LED) 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), a light emitting diode (LED) display and a plasma display. In some embodiments, the display device may be a touch screen.

[0153] 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 a 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).

[0154] 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 active front wheel steering 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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).

[0160] 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 to implement the embodiments. 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.

[0161] The computer program product provided in the embodiment of the present application includes one or more computer programs / instructions, and when the computer program / instructions are executed by the processor, the process or function described in the embodiment of the present application is generated in whole or in part. 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 to another website site, a computer, a server, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. 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 integrations. 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 disk (SSD)), etc.

[0162] 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.

[0163] 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. An active front wheel steering control method, characterized in that: include: Obtain the driving speed and steering wheel angle of the vehicle during driving to obtain the front wheel angle; Based on the current road adhesion coefficient and the vehicle driving style, the first additional front wheel steering angle output by the active steering controller is constrained to obtain the second additional front wheel steering angle, which specifically includes: Get the current road adhesion coefficient; Based on the driver's vehicle control, the current vehicle driving style is identified through a pre-trained driving style model; Dynamically generate a corresponding weight coefficient according to different road adhesion coefficients and vehicle driving styles, and the weight coefficient is less than or equal to 1; adjusting the first additional front wheel turning angle based on the weight coefficient to obtain the second additional front wheel turning angle; The first additional front wheel steering angle output by the active steering controller is obtained by: Estimate the center of mass slip angle based on the tire's cornering stiffness; Construct a disturbance observer to estimate the system disturbance and calculate the disturbance estimate; combining the disturbance estimation value, the center of mass sideslip angle and the active steering controller, and determining a control amount of the active steering controller as the first additional front wheel steering angle; Based on the front wheel steering angle and the second additional front wheel steering angle, an ideal front wheel steering angle is obtained and input into a steer-by-wire actuator for execution.

2. The active front wheel steering control method according to claim 1, characterized in that: The step of obtaining the vehicle speed and steering wheel angle during the vehicle's driving process to obtain the front wheel angle comprises: Acquiring current state data of the vehicle, wherein the current state data includes: one or more of driving speed, yaw angular velocity, and lateral acceleration; Based on the driver's steering intention, generating the corresponding steering wheel angle; obtaining a steer-by-wire transmission ratio based on the current driving speed, the steering wheel angle, the yaw rate and the lateral acceleration; The steering wheel angle is converted into the front wheel angle based on the steer-by-wire transmission ratio.

3. The active front wheel steering control method according to claim 1, characterized in that: The step of dynamically generating corresponding weight coefficients according to different road adhesion coefficients and vehicle driving styles includes: Inputting the road adhesion coefficient and the weight coefficient into a regression equation generation model to establish a regression equation between the road adhesion coefficient and the weight coefficient; quantifying the vehicle driving style to obtain a driving style quantization value; The driving style quantification value is introduced into the regression equation, and the influence of the vehicle driving style on the weight coefficient is adjusted by the driving style quantification value.

4. The active front wheel steering control method according to claim 1, characterized in that: The step of estimating the center of mass slip angle based on the tire's cornering stiffness comprises: The linear relationship between tire lateral force and slip angle is established, and the expression of initial tire cornering stiffness is obtained; Obtaining the front and rear axle slip angles of the vehicle in a steady state, and calculating the absolute value of the difference between the front and rear axle slip angles; Substituting the absolute value into the expression of the initial tire cornering stiffness, the cornering stiffness of the tires on the front axle and the rear axle during the vehicle's driving process is obtained.

5. The active front wheel steering control method according to claim 4, characterized in that: The step of constructing a disturbance observer to estimate the system disturbance and calculate the compensation value comprises: Based on the front wheel steering angle and the cornering stiffness, a desired yaw rate and a desired center-of-mass slip angle are obtained by a vehicle dynamics model; Based on the desired yaw rate and the desired center-of-mass sideslip angle, an observation error is defined, and a center-of-mass sideslip angle observer is constructed based on the observation error; An intermediate variable is introduced to design a disturbance observer, and a disturbance observer for nonlinear disturbance observation is constructed based on the center of mass sideslip angle observer. Based on the disturbance observer, a disturbance estimation value is obtained.

6. An electronic device, characterized in that: The electronic device comprises: 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 active front wheel steering control method as described in any one of claims 1-5.

7. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instructions are executed by a processor, the steps of the active front wheel steering control method as described in any one of claims 1 to 5 are implemented.

8. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the active front wheel steering control method as described in any one of claims 1 to 5 are implemented.

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