Vehicle rear wheel steering control method and device, electronic equipment and readable storage medium

Abstract

The invention provides a vehicle rear wheel steering control method and device, electronic equipment and a readable storage medium, and the method comprises the steps: determining a predicted lateral acceleration of a vehicle according to a motion state parameter and a steering control parameter of the vehicle, determining a corrected lateral acceleration of the vehicle according to the predicted lateral acceleration and an actual lateral acceleration of the vehicle, and determining the corrected lateral acceleration of the vehicle according to the corrected lateral acceleration. According to the corrected lateral acceleration of the vehicle and the target rear axle side deflection flexibility change amount, the control amount of the target rear wheel rotation angle of the vehicle is determined, and rear wheels of the vehicle are controlled to steer according to the control amount of the target rear wheel rotation angle of the vehicle. According to the method, the actual lateral acceleration of the vehicle is corrected by utilizing the predicted lateral acceleration of the vehicle, and the corrected lateral acceleration of the vehicle and the target rear axle lateral deflection flexibility change quantity are combined to quantify the control quantity of the target rear wheel steering angle, so that the determined control quantity of the target rear wheel steering angle is more accurate; therefore, the steering control accuracy of the rear wheels of the vehicle can be improved.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a method, device, electronic device, and computer-readable storage medium for controlling the rear wheel steering of a vehicle. Background Technology

[0002] With the rapid development of the automotive industry and the increasing demands of consumers for vehicle performance, vehicle handling, stability, and safety have become core objectives in automotive design and development. To further enhance vehicle handling performance, rear-wheel steering technology has gradually become an important feature in high-end models and intelligent driving systems.

[0003] Currently, the main vehicle rear-wheel steering control technology solutions use a lookup table method. Specifically, based on two parameters—vehicle speed and steering wheel angle—the rear-wheel angle is determined using a pre-set table (i.e., the correspondence between vehicle speed, steering wheel angle, and rear-wheel angle), and the rear wheels are steered according to the rear-wheel angle.

[0004] However, the above-mentioned technical solutions rely on pre-set discrete data points and cannot dynamically adapt to complex transient changes in vehicle status. Consequently, they cannot adjust the rear wheel steering angle in real time to match these changes, resulting in low precision in rear wheel steering control. Summary of the Invention

[0005] This application provides a method, apparatus, electronic device, and computer-readable storage medium for controlling the rear wheel steering of a vehicle, aiming to improve the problem of low accuracy in the rear wheel steering control of a vehicle.

[0006] In a first aspect, embodiments of this application provide a vehicle rear-wheel steering control method, applied to a vehicle controller, the method comprising:

[0007] The vehicle's motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change are obtained.

[0008] The predicted lateral acceleration of the vehicle is determined based on the vehicle's motion state parameters and steering control parameters.

[0009] Based on the predicted lateral acceleration and the actual lateral acceleration of the vehicle, the corrected lateral acceleration of the vehicle is determined.

[0010] The control amount of the target rear wheel steering angle of the vehicle is determined based on the corrected lateral acceleration of the vehicle and the change in the target rear axle lateral compliance.

[0011] The vehicle's rear wheels are steered according to the control amount of the target rear wheel steering angle.

[0012] By using the vehicle's predicted lateral acceleration to correct the vehicle's actual lateral acceleration, the impact of sensor, actuator, and system transmission delays on the vehicle's rear wheel steering control in practical applications can be compensated, improving the real-time performance of the vehicle's rear wheel steering control. Furthermore, by combining the vehicle's corrected lateral acceleration with the change in the target rear axle lateral compliance, the control quantity of the target rear wheel angle can be quantified, making the determined control quantity of the target rear wheel angle more accurate, thereby improving the precision of the vehicle's rear wheel steering control.

[0013] Optionally, the vehicle's motion parameters include at least one of vehicle speed, lateral acceleration, and yaw rate, and the vehicle's steering control parameters include at least one of front wheel steering angle and rear wheel steering angle.

[0014] Optionally, obtaining the target rear axle lateral compliance change of the vehicle includes:

[0015] Obtain the vehicle speed and the corresponding relationship between the preset vehicle speed and the change in rear axle lateral deflection compliance;

[0016] The target change in rear axle lateral flexibility is determined based on the vehicle speed and the correspondence between the vehicle speed and the change in rear axle lateral flexibility.

[0017] By determining the target rear axle side slip change based on the vehicle speed and the correlation between vehicle speed and rear axle side slip change, the target rear axle side slip change can be obtained directly by querying based on the vehicle speed, thus improving the efficiency of obtaining the target rear axle side slip change.

[0018] Optionally, determining the predicted lateral acceleration of the vehicle based on the vehicle's motion state parameters and steering control parameters includes:

[0019] The vehicle's motion state parameters and steering control parameters are input into a pre-generated vehicle dynamics reference model to obtain the vehicle's predicted lateral acceleration.

[0020] By using a pre-generated vehicle dynamics reference model, which comprehensively considers the vehicle's motion state parameters and steering control parameters, the lateral acceleration of the vehicle can be predicted more quickly and accurately, thus improving the efficiency and accuracy of obtaining the predicted lateral acceleration.

[0021] Optionally, determining the corrected lateral acceleration of the vehicle based on the predicted lateral acceleration and the actual lateral acceleration includes:

[0022] Obtain the target weighting coefficients;

[0023] The corrected lateral acceleration of the vehicle is determined based on the target weighting coefficient, the predicted lateral acceleration of the vehicle, and the actual lateral acceleration.

[0024] By using a target weighting coefficient, the vehicle's predicted lateral acceleration, and the actual lateral acceleration, the corrected lateral acceleration of the vehicle is determined. In other words, by introducing a target weighting coefficient, the weights of the vehicle's predicted lateral acceleration and actual lateral acceleration can be dynamically adjusted, thereby generating a more accurate corrected lateral acceleration that can more comprehensively reflect the vehicle's actual dynamic characteristics.

[0025] Optionally, obtaining the target weighting coefficient includes:

[0026] Obtain the initial weighting coefficients, the variance of the actual lateral acceleration of the vehicle, and the rate of change of the front wheel steering angle of the vehicle;

[0027] The initial weighting coefficients are updated based on the variance of the vehicle's actual lateral acceleration and the rate of change of the vehicle's front wheel steering angle to obtain the target weighting coefficients.

[0028] By introducing the variance of the vehicle's actual lateral acceleration and the rate of change of the vehicle's front wheel steering angle, the initial weighting coefficients can be dynamically adjusted, making the determined target weighting coefficients more adaptable to the real-time dynamic changes of the vehicle. Furthermore, this can improve the sensitivity of the vehicle's actual lateral acceleration correction and reduce the lag of the vehicle's actual lateral acceleration correction.

[0029] Optionally, after the step of determining the control amount of the target rear wheel steering angle of the vehicle based on the corrected lateral acceleration of the vehicle and the target rear axle lateral compliance change, the method further includes:

[0030] Obtain the preset maximum rear wheel steering angle control value;

[0031] The control amount of the target rear wheel steering angle of the vehicle is compared with the control amount of the maximum rear wheel steering angle.

[0032] If the control amount of the target rear wheel steering angle of the vehicle is greater than the control amount of the maximum rear wheel steering angle, then the control amount of the maximum rear wheel steering angle is taken as the control amount of the target rear wheel steering angle of the vehicle.

[0033] If the control amount of the target rear wheel steering angle of the vehicle is less than or equal to the control amount of the maximum rear wheel steering angle, then the step of controlling the rear wheels of the vehicle to steer according to the control amount of the target rear wheel steering angle of the vehicle is executed.

[0034] By using the control value of the maximum rear wheel steering angle as the control value of the target rear wheel steering angle when the control value of the target rear wheel steering angle is greater than the control value of the maximum rear wheel steering angle, the rear wheel steering angle can be effectively prevented from exceeding the safe range, thereby improving vehicle safety. For example, in extreme conditions (such as emergency avoidance or high-speed steering), this step can avoid the risk of loss of vehicle control caused by excessive rear wheel steering angle.

[0035] Secondly, embodiments of this application provide a rear-wheel steering control device for a vehicle, applied to a vehicle controller, the device comprising:

[0036] The data acquisition module is used to acquire the vehicle's motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change.

[0037] The lateral acceleration prediction module is used to determine the predicted lateral acceleration of the vehicle based on the vehicle's motion state parameters and steering control parameters.

[0038] The lateral acceleration correction module is used to determine the corrected lateral acceleration of the vehicle based on the predicted lateral acceleration and the actual lateral acceleration of the vehicle.

[0039] The target rear wheel steering angle control amount determination module is used to determine the control amount of the target rear wheel steering angle of the vehicle based on the corrected lateral acceleration of the vehicle and the change in the target rear axle lateral deflection compliance.

[0040] The vehicle rear wheel steering control module is used to control the rear wheels of the vehicle to steer according to the control amount of the target rear wheel steering angle.

[0041] Optionally, the vehicle's motion parameters include at least one of vehicle speed, lateral acceleration, and yaw rate, and the vehicle's steering control parameters include at least one of front wheel steering angle and rear wheel steering angle.

[0042] Optionally, the data acquisition module includes:

[0043] The data correspondence acquisition submodule is used to acquire the vehicle speed and the correspondence between the preset vehicle speed and the change in rear axle lateral deflection compliance.

[0044] The target rear axle lateral deflection change determination submodule is used to determine the target rear axle lateral deflection change based on the vehicle speed and the correspondence between the vehicle speed and the rear axle lateral deflection change.

[0045] Optionally, the lateral acceleration prediction module includes:

[0046] The vehicle dynamics reference model processing submodule is used to input the vehicle's motion state parameters and steering control parameters into a pre-generated vehicle dynamics reference model to obtain the vehicle's predicted lateral acceleration.

[0047] Optionally, the lateral acceleration correction module includes:

[0048] The target weighted coefficient acquisition submodule is used to obtain the target weighted coefficients;

[0049] The lateral acceleration correction submodule is used to determine the corrected lateral acceleration of the vehicle based on the target weighting coefficient, the predicted lateral acceleration of the vehicle, and the actual lateral acceleration.

[0050] Optionally, the target weighting coefficient acquisition submodule includes:

[0051] An initial weighting coefficient acquisition unit is used to acquire the initial weighting coefficients, the variance of the actual lateral acceleration of the vehicle, and the rate of change of the front wheel steering angle of the vehicle;

[0052] The initial weighting coefficient update unit is used to update the initial weighting coefficients based on the variance of the actual lateral acceleration of the vehicle and the rate of change of the front wheel steering angle of the vehicle, so as to obtain the target weighting coefficients.

[0053] Optionally, the device further includes:

[0054] The maximum rear wheel steering angle control quantity acquisition module is used to acquire the preset maximum rear wheel steering angle control quantity;

[0055] The data comparison module is used to compare the control amount of the target rear wheel steering angle of the vehicle with the control amount of the maximum rear wheel steering angle;

[0056] The first data comparison result module is used to take the control amount of the maximum rear wheel steering angle as the control amount of the target rear wheel steering angle of the vehicle if the control amount of the target rear wheel steering angle of the vehicle is greater than the control amount of the maximum rear wheel steering angle.

[0057] The second data comparison result module is used to execute the step of controlling the rear wheels of the vehicle to steer according to the control amount of the target rear wheel steering angle if the control amount of the target rear wheel steering angle of the vehicle is less than or equal to the control amount of the maximum rear wheel steering angle.

[0058] Thirdly, embodiments of this application also provide an electronic device, including: a processor; and a memory for storing processor-executable instructions, wherein the processor is configured to execute the instructions to implement the vehicle rear-wheel steering control method as described above.

[0059] Fourthly, embodiments of this application also provide a computer-readable storage medium that, when the instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform the vehicle rear-wheel steering control method as described above.

[0060] In this embodiment, the vehicle's motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change are acquired. Based on the vehicle's motion state parameters and steering control parameters, the predicted lateral acceleration of the vehicle is determined. Based on the predicted lateral acceleration and the actual lateral acceleration, the corrected lateral acceleration of the vehicle is determined. Based on the corrected lateral acceleration and the target rear axle lateral compliance change, the control value of the target rear wheel steering angle is determined. The rear wheels of the vehicle are then steered based on the control value of the target rear wheel steering angle. This application, by using the predicted lateral acceleration to correct the actual lateral acceleration of the vehicle, can compensate for the impact of sensor, actuator, and system transmission delays on the rear wheel steering control in practical applications, improving the real-time performance of the rear wheel steering control. Furthermore, by combining the corrected lateral acceleration with the target rear axle lateral compliance change to quantify the control value of the target rear wheel steering angle, the determined control value of the target rear wheel steering angle is more accurate, thereby improving the precision of the rear wheel steering control.

[0061] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0062] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0063] Figure 1 This is one of the flowcharts of a vehicle rear wheel steering control method provided in an embodiment of this application;

[0064] Figure 2(a) is a schematic diagram of the angle relationship of a high-speed steady-state steering linear two-wheel model considering the K&C characteristics of the steering and suspension system provided in an embodiment of this application;

[0065] Figure 2(b) is a schematic diagram of the force analysis of a high-speed steady-state steering linear two-wheel model considering the K&C characteristics of the steering and suspension system provided in an embodiment of this application;

[0066] Figure 3This is a schematic diagram of constructing a rear wheel steering angle-rear axle side deflection compliance mapping model provided in an embodiment of this application;

[0067] Figure 4 This is one of the schematic flowcharts of a vehicle rear wheel steering control method provided in an embodiment of this application;

[0068] Figure 5 This is a second schematic flowchart of a vehicle rear wheel steering control method provided in an embodiment of this application;

[0069] Figure 6 This is a second flowchart of a vehicle rear wheel steering control method provided in an embodiment of this application;

[0070] Figure 7 This is a structural diagram of the vehicle rear wheel steering control device provided in the embodiments of this application;

[0071] Figure 8 This is a structural diagram of the electronic device provided in the embodiments of this application. Detailed Implementation

[0072] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0073] This application provides a vehicle rear-wheel steering control method, comprising: acquiring vehicle motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change; determining a predicted lateral acceleration of the vehicle based on the vehicle motion state parameters and steering control parameters; determining a corrected lateral acceleration of the vehicle based on the predicted lateral acceleration and actual lateral acceleration; determining a control amount for the target rear wheel steering angle of the vehicle based on the corrected lateral acceleration and target rear axle lateral compliance change; and controlling the rear wheels of the vehicle to steer based on the control amount for the target rear wheel steering angle.

[0074] This application corrects the actual lateral acceleration of a vehicle by utilizing the predicted lateral acceleration of the vehicle. This can compensate for the impact of sensor, actuator, and system transmission delays on the rear wheel steering control in practical applications, thereby improving the real-time performance of the rear wheel steering control. Furthermore, by combining the corrected lateral acceleration of the vehicle with the change in the target rear axle lateral compliance, the control quantity of the target rear wheel angle is quantified, making the determined control quantity of the target rear wheel angle more accurate, thus improving the precision of the rear wheel steering control.

[0075] Example 1

[0076] This application provides a rear-wheel steering control method for a vehicle, applied to the vehicle controller. Please refer to [link / reference needed]. Figure 1 This includes the following steps:

[0077] Step 101: Obtain the vehicle's motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change.

[0078] Step 102: Determine the predicted lateral acceleration of the vehicle based on the vehicle's motion state parameters and steering control parameters.

[0079] Step 103: Determine the corrected lateral acceleration of the vehicle based on the predicted lateral acceleration and the actual lateral acceleration.

[0080] Step 104: Determine the control amount of the target rear wheel steering angle of the vehicle based on the corrected lateral acceleration of the vehicle and the change in the target rear axle lateral compliance.

[0081] Step 105: Control the rear wheels of the vehicle to steer according to the control amount of the target rear wheel steering angle.

[0082] In some embodiments of this application, a rear axle lateral compliance model and a rear wheel steering angle-rear axle lateral compliance mapping model are pre-constructed.

[0083] After completing the construction of the rear axle lateral compliance model and the rear wheel angle-rear axle lateral compliance mapping model, the vehicle's motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change are obtained. The vehicle's motion state parameters include at least one of vehicle speed, lateral acceleration, and yaw rate, and the vehicle's steering control parameters include at least one of front wheel angle and rear wheel angle.

[0084] To overcome the impact of sensor, actuator, and system transmission delays on rear-wheel steering control in practical applications, the vehicle's lateral acceleration can be predicted based on the vehicle's motion state parameters and steering control parameters, thus obtaining the predicted lateral acceleration. Furthermore, as... Figure 4 As shown, the actual lateral acceleration 'a' of the vehicle can be collected using a real vehicle. y The predicted lateral acceleration of the vehicle can be obtained through a pre-generated vehicle dynamics reference model. This will then affect the vehicle's actual lateral acceleration a. y And the vehicle's predicted lateral acceleration The input is fed into the state corrector, which can utilize the vehicle's predicted lateral acceleration. The actual lateral acceleration a of the vehicle y After correction, the corrected lateral acceleration a of the vehicle is obtained. y* It should be noted that, in the embodiments of this application, the reference model is the same as the vehicle dynamics reference model.

[0085] The change in the target's lateral compliance, i.e., the target's ΔD, is obtained through the target generator. r The change in the target's rear axle side compliance, i.e., the target's ΔD. r and the vehicle's corrected lateral acceleration a y *This input is fed into the rear-wheel steering control model, which can then calculate the control quantity δ for the target rear-wheel steering angle of the vehicle. ref,r * Additionally, it should be noted that the rear-wheel steering control model may require more data in the actual calculation of the target rear wheel steering angle, not just the change in target rear axle lateral compliance and the vehicle's corrected lateral acceleration.

[0086] After the rear-wheel steering control model obtains the control value of the target rear wheel steering angle, it can send this control value to the vehicle's rear-wheel steering system. Upon receiving the target rear wheel steering angle control value from the rear-wheel steering control model, the vehicle's rear-wheel steering system controls the vehicle's rear wheels to steer according to this target angle.

[0087] This application corrects the actual lateral acceleration of a vehicle by utilizing the predicted lateral acceleration of the vehicle. This can compensate for the impact of sensor, actuator, and system transmission delays on the rear wheel steering control in practical applications, thereby improving the real-time performance of the rear wheel steering control. Furthermore, by combining the corrected lateral acceleration of the vehicle with the change in the target rear axle lateral compliance, the control quantity of the target rear wheel angle is quantified, making the determined control quantity of the target rear wheel angle more accurate, thus improving the precision of the rear wheel steering control.

[0088] In some embodiments of this application, the specific implementation process for constructing the rear axle lateral deflection compliance model is as follows: As shown in formula (1), the vehicle understeer coefficient is defined as the difference between the front axle lateral deflection compliance and the rear axle lateral deflection compliance. As shown in Figure 2(a), the front axle lateral deflection compliance is defined as shown in formula (2). The rear axle lateral deflection compliance is defined as shown in formula (3).

[0089] K=D f -D r Formula (1)

[0090] Where K is the understeer coefficient of the vehicle, and D f For front axle lateral compliance, D r This refers to the rear axle lateral flexibility.

[0091]

[0092] Among them, D f For front axle lateral compliance, δ s To account for the change in front wheel steering angle after flexible deformation considering the K (kinematic) and C (compliance) characteristics of the front suspension, a y α is the lateral acceleration, g is the gravitational acceleration, and α is the acceleration due to gravity. f This is the slip angle of the front tire.

[0093]

[0094] Among them, D r For rear axle lateral compliance, δ r The angle between the mid-plane of the rear wheel and the longitudinal plane of the vehicle body, also known as the rear wheel steering angle, is α. y α is the lateral acceleration, g is the gravitational acceleration, and α is the acceleration due to gravity. r This refers to the slip angle of the rear tire.

[0095] Furthermore, δ in Figure 2(a) ref,f The front wheel steering angle, δ, is calculated based on the kinematic ratio of the steering wheel and steering system. f It is the angle between the mid-plane of the front wheel and the longitudinal plane of the vehicle body, V f V is the front axle speed. r This is the rear axle speed.

[0096] The front axle lateral flexibility and rear axle lateral flexibility jointly affect the vehicle's understeer coefficient, and respectively affect the establishment of the lateral forces on the front axle and the rear axle. The smaller the lateral flexibility, the faster the lateral forces are established. Reducing the rear axle lateral flexibility can improve the vehicle's understeer coefficient, improve vehicle stability and system natural frequency, shorten lag time, reduce overshoot, and optimize transient response. As shown in Figure 2(b), the vehicle's dynamic equations are shown in equations (4) and (5).

[0097] ma y =F y,f +F y,r Formula (4)

[0098]

[0099] Where m is the total vehicle mass, a y For lateral acceleration, F y,f F is the lateral force on the front axle. y,r For the lateral force on the rear axle, I z Let yaw moment of inertia be the moment of inertia of the entire vehicle. Let yaw rate be denoted as α, a be the distance from the vehicle's center of mass to the front axle, and b be the distance from the vehicle's center of mass to the rear axle.

[0100] Furthermore, V in Figure 2(b) x The velocity along the longitudinal direction of the vehicle body, ω r ω represents the yaw rate.

[0101] According to the vehicle's dynamic equations, the lateral force on the front axle has a positive feedback effect on both lateral acceleration and yaw rate, while the lateral force on the rear axle has a positive feedback effect on lateral acceleration and a negative feedback effect on yaw rate.

[0102] For traditional vehicles, rear axle lateral flexibility is mainly related to tire lateral stiffness and suspension K&C characteristics. According to the definition of rear axle lateral flexibility given in formula (3), changing the rear wheel angle by steering the rear wheels effectively changes the angle between the rear wheel midplane and the vehicle's longitudinal plane, such as... Figure 3 As shown, the angle between the rear wheel midplane and the vehicle body longitudinal plane changes from the initial δ r Changed to δ r +Δδ r In vehicles equipped with rear-wheel steering, the rear wheels rotate relative to the direction of the rear axle's velocity. The rear axle lateral deflection flexibility primarily depends on the angle between the rear axle's velocity direction and the vehicle's longitudinal plane. Therefore, vehicles with rear-wheel steering can effectively change the rear axle lateral deflection flexibility by controlling the steering angle of the rear wheels. Figure 3 As shown, the rear axle lateral compliance changes from the initial α r -δ r Changed to α r -(δ r +Δδ r ).

[0103] The specific implementation process of constructing the rear wheel steering angle-rear axle lateral deflection compliance mapping model is as follows: Figure 3 As shown, the rear axle lateral deflection compliance with rear wheel steering can be expressed as shown in formula (6).

[0104]

[0105] Among them, D r * Rear axle lateral deflection compliance with rear-wheel steering, δ r The angle between the mid-plane of the rear wheel and the longitudinal plane of the vehicle body, also known as the rear wheel steering angle, is Δδ. r This represents the increase in the angle between the rear wheel center plane and the vehicle's longitudinal plane, which is also the increase in the rear wheel steering angle. y α is the lateral acceleration, g is the gravitational acceleration, and α is the acceleration due to gravity. r This refers to the slip angle of the rear tire.

[0106] Combining formula (3), and further reorganizing formula (6), we can obtain formula (7).

[0107]

[0108] Among them, D r * Rear axle lateral deflection compliance with rear-wheel steering, δ r The angle between the mid-plane of the rear wheel and the longitudinal plane of the vehicle body, also known as the rear wheel steering angle, is Δδ. r This represents the increase in the angle between the rear wheel center plane and the vehicle's longitudinal plane, which is also the increase in the rear wheel steering angle. y α is the lateral acceleration, g is the gravitational acceleration, and α is the acceleration due to gravity. r D is the slip angle of the rear tire. r For the rear axle lateral compliance, ΔD r This represents the change in the rear axle lateral compliance.

[0109] Based on the rear axle lateral flexibility, the formula for calculating the control amount of the rear wheel steering angle is shown in formula (8).

[0110]

[0111] Where, δ ref,r ΔD is the control value for the rear wheel steering angle. r a represents the change in rear axle lateral compliance. y denoted as lateral acceleration, and g as gravitational acceleration.

[0112] Step 101 includes:

[0113] Step 1011: Obtain the vehicle speed and the corresponding relationship between the preset vehicle speed and the change in rear axle lateral compliance.

[0114] Step 1012: Determine the target rear axle lateral flexibility change based on the vehicle speed and the correspondence between the vehicle speed and the change in rear axle lateral flexibility.

[0115] In some embodiments of this application, such as Figure 5 As shown, the target generator can determine the change in the target rear axle side compliance of the vehicle by looking up a table. Specifically, the vehicle speed V can be pre-constructed. x Change in rear axle lateral compliance ΔD r The correspondence between them. With the current vehicle speed obtained, the corresponding rear axle side slip change can be determined by searching the pre-built correspondence between vehicle speed and rear axle side slip change based on the current vehicle speed. The rear axle side slip change corresponding to the current vehicle speed is the target rear axle side slip change.

[0116] Among them, in constructing vehicle speed V x Change in rear axle lateral compliance ΔD r When considering the correspondence between these parameters, in order to meet the requirements of low-speed maneuverability and high-speed stability, in the low-speed domain (V... x <Vx0 When ), through negative ΔD r The rear wheels rotate in the opposite direction to the front wheels, enhancing yaw response sensitivity; in the high-speed domain (V x >V x0 ) through positive ΔD r This allows the rear wheels to rotate in the same direction as the front wheels, improving stability and phase characteristics. Specifically, V... x0 This application does not specify the numerical value of the vehicle speed threshold.

[0117] In addition, the vehicle speed threshold V can be segmented. x0 (For example: V) x0 Divided into [V] x1 V x2 ], where V x1 V is the first vehicle speed threshold. x2 If the second speed threshold is used, then the speed < V x1 With ΔD r The mapping relationship between them, and the vehicle speed in [V] x1 V x2 ] and ΔD r The mapping relationship between them and the vehicle speed greater than V x2 With ΔD r The mapping relationships between them can all be subjectively calibrated and confirmed by the user.

[0118] This application determines the target rear axle side slip change based on the vehicle speed and the correspondence between vehicle speed and rear axle side slip change. The target rear axle side slip change can be obtained directly by querying based on the vehicle speed, thus improving the efficiency of obtaining the target rear axle side slip change.

[0119] Step 102 includes:

[0120] Step 1021: Input the vehicle's motion state parameters and steering control parameters into the pre-generated vehicle dynamics reference model to obtain the vehicle's predicted lateral acceleration.

[0121] In some embodiments of this application, the pre-generated vehicle dynamics reference model is a predictive model that can predict the lateral acceleration of the vehicle based on the vehicle's motion state parameters and steering control parameters, thereby obtaining the predicted lateral acceleration of the vehicle.

[0122] The vehicle's motion parameters include at least one of vehicle speed, lateral acceleration, and yaw rate, and the vehicle's steering control parameters include at least one of front wheel steering angle and rear wheel steering angle.

[0123] like Figure 4As shown, at least one of the following parameters—vehicle speed, lateral acceleration, yaw rate, front wheel steering angle, and rear wheel steering angle—is used as input to a pre-generated vehicle dynamics reference model. The pre-generated vehicle dynamics reference model can then automatically output the predicted lateral acceleration of the vehicle.

[0124] This application uses a pre-generated vehicle dynamics reference model to comprehensively consider the vehicle's motion state parameters and steering control parameters to predict the vehicle's lateral acceleration. This allows for faster and more accurate acquisition of the predicted lateral acceleration, improving the efficiency and accuracy of predicting the vehicle's lateral acceleration.

[0125] Step 103 includes:

[0126] Step 1031: Obtain the target weighting coefficients.

[0127] Step 1032: Determine the corrected lateral acceleration of the vehicle based on the target weighting coefficient, the predicted lateral acceleration of the vehicle, and the actual lateral acceleration.

[0128] In some embodiments of this application, such as Figure 5 As shown, when correcting the actual lateral acceleration of the vehicle through the state corrector, the target weighting coefficient can be obtained first. After obtaining the target weighting coefficient, the corrected lateral acceleration of the vehicle can be determined based on the target weighting coefficient, the predicted lateral acceleration of the vehicle, and the actual lateral acceleration. The specific calculation method of the corrected lateral acceleration of the vehicle is shown in formula (9).

[0129]

[0130] Among them, a y * The corrected lateral acceleration of the vehicle, where k is the target weighting coefficient. For the predicted lateral acceleration of the vehicle, a y This represents the vehicle's actual lateral acceleration.

[0131] This application determines the corrected lateral acceleration of a vehicle based on a target weighting coefficient, the predicted lateral acceleration, and the actual lateral acceleration. In other words, by introducing a target weighting coefficient, the weights of the predicted lateral acceleration and the actual lateral acceleration of the vehicle can be dynamically adjusted, thereby generating a more accurate corrected lateral acceleration that can more comprehensively reflect the actual dynamic characteristics of the vehicle.

[0132] Step 1031 includes:

[0133] Sub-step 11: Obtain the initial weighting coefficients, the variance of the vehicle's actual lateral acceleration, and the rate of change of the vehicle's front wheel steering angle.

[0134] Sub-step 12 updates the initial weighting coefficients based on the variance of the vehicle's actual lateral acceleration and the rate of change of the vehicle's front wheel steering angle to obtain the target weighting coefficients.

[0135] In some embodiments of this application, the specific implementation process for obtaining the target weighting coefficients is as follows: Figure 5 As shown, the initial weighting coefficients and the variance σ(a) of the vehicle's actual lateral acceleration are obtained. y and the rate of change of the vehicle's front wheel steering angle The initial weighting coefficients are updated based on the variance of the vehicle's actual lateral acceleration and the rate of change of the vehicle's front wheel steering angle to obtain the target weighting coefficient k.

[0136] The larger the target weighting coefficient corresponding to the predicted lateral acceleration of the vehicle, the greater the degree of lead correction. The target weighting coefficient can be determined according to fuzzy rules. An example of the design method for fuzzy rules is to consider the variance of the vehicle's actual lateral acceleration and the rate of change of the vehicle's front wheel steering angle. For example, the larger the variance of the vehicle's actual lateral acceleration, the more intense the dynamic process of the vehicle, and the more obvious the delay. In this case, the initial weighting coefficient is increased to obtain the target weighting coefficient. The smaller the variance of the vehicle's actual lateral acceleration, the more stable the process of the vehicle, in this case, the initial weighting coefficient is decreased to obtain the target weighting coefficient. The larger the rate of change of the vehicle's front wheel steering angle, the more intense the driver's operation, and the more obvious the delay. In this case, the initial weighting coefficient is increased to obtain the target weighting coefficient. Conversely, the smaller the rate of change of the vehicle's front wheel steering angle, the more stable the driver's operation, in this case, the initial weighting coefficient is decreased to obtain the target weighting coefficient. Therefore, by dividing the variance of the vehicle's actual lateral acceleration into two levels (large and small) and the rate of change of the vehicle's front wheel steering angle into two levels (fast and slow), fuzzy rules are constructed.

[0137] This application introduces the variance of the vehicle's actual lateral acceleration and the rate of change of the vehicle's front wheel steering angle to dynamically adjust the initial weighting coefficients, thereby making the determined target weighting coefficients more adaptable to the real-time dynamic changes of the vehicle. Furthermore, it can improve the sensitivity of the vehicle's actual lateral acceleration correction and reduce the lag of the vehicle's actual lateral acceleration correction.

[0138] Example 2

[0139] This application provides a method for controlling the rear-wheel steering of a vehicle. Please refer to [link / reference]. Figure 6 After step 104, the vehicle rear wheel steering control method provided in this application embodiment further includes:

[0140] Step 601: Obtain the preset maximum rear wheel steering angle control value.

[0141] Step 602: Compare the control amount of the target rear wheel steering angle of the vehicle with the control amount of the maximum rear wheel steering angle.

[0142] Step 603: If the control amount of the target rear wheel steering angle of the vehicle is greater than the control amount of the maximum rear wheel steering angle, then the control amount of the maximum rear wheel steering angle is taken as the control amount of the target rear wheel steering angle of the vehicle.

[0143] Step 604: If the control amount of the target rear wheel steering angle of the vehicle is less than or equal to the control amount of the maximum rear wheel steering angle, then execute the step of controlling the rear wheels of the vehicle to steer according to the control amount of the target rear wheel steering angle of the vehicle.

[0144] In some embodiments of this application, to prevent excessive rear wheel steering angles during high-speed operation, it is necessary to limit the control value of the target rear wheel steering angle of the vehicle. Specifically, a preset maximum rear wheel steering angle control value is obtained. It should be noted that this application does not specifically limit the value of the preset maximum rear wheel steering angle control value, which can be calculated and adjusted according to vehicle parameters. The control value of the target rear wheel steering angle is compared with the control value of the maximum rear wheel steering angle. If the control value of the target rear wheel steering angle is greater than the control value of the maximum rear wheel steering angle, the control value of the maximum rear wheel steering angle is used as the control value of the target rear wheel steering angle, and then the step of controlling the rear wheels of the vehicle to steer according to the control value of the target rear wheel steering angle is executed. If the control value of the target rear wheel steering angle is less than or equal to the control value of the maximum rear wheel steering angle, the step of directly controlling the rear wheels of the vehicle to steer according to the control value of the target rear wheel steering angle is executed.

[0145] This application, by using the control value of the maximum rear wheel steering angle as the control value of the target rear wheel steering angle when the control value of the target rear wheel steering angle is greater than the control value of the maximum rear wheel steering angle, can effectively prevent the rear wheel steering angle from exceeding the safe range, thereby improving vehicle safety. For example, in extreme conditions (such as emergency avoidance or high-speed steering), this step can avoid the risk of vehicle loss of control caused by excessive rear wheel steering angle.

[0146] This application also provides a rear-wheel steering control device 70 for use in a vehicle's overall controller. Please refer to [link / reference needed]. Figure 7 ,include:

[0147] The data acquisition module 710 is used to acquire the vehicle's motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change.

[0148] The lateral acceleration prediction module 720 is used to determine the predicted lateral acceleration of the vehicle based on the vehicle's motion state parameters and steering control parameters.

[0149] The lateral acceleration correction module 730 is used to determine the corrected lateral acceleration of the vehicle based on the predicted lateral acceleration and the actual lateral acceleration of the vehicle.

[0150] The target rear wheel steering angle control amount determination module 740 is used to determine the control amount of the vehicle's target rear wheel steering angle based on the vehicle's corrected lateral acceleration and the change in the target rear axle lateral compliance.

[0151] The vehicle rear wheel steering control module 750 is used to control the rear wheels of the vehicle to steer according to the control amount of the target rear wheel steering angle.

[0152] Optionally, the vehicle's motion parameters include at least one of vehicle speed, lateral acceleration, and yaw rate, and the vehicle's steering control parameters include at least one of front wheel steering angle and rear wheel steering angle.

[0153] Optionally, the data acquisition module 710 includes:

[0154] The data correspondence acquisition submodule is used to acquire the vehicle speed and the correspondence between the preset vehicle speed and the change in rear axle lateral compliance.

[0155] The target rear axle lateral flexibility change determination submodule is used to determine the target rear axle lateral flexibility change based on the vehicle speed and the correspondence between vehicle speed and rear axle lateral flexibility change.

[0156] Optionally, the lateral acceleration prediction module 720 includes:

[0157] The vehicle dynamics reference model processing submodule is used to input the vehicle's motion state parameters and steering control parameters into the pre-generated vehicle dynamics reference model to obtain the vehicle's predicted lateral acceleration.

[0158] Optionally, the lateral acceleration correction module 730 includes:

[0159] The target weighted coefficient acquisition submodule is used to obtain the target weighted coefficients;

[0160] The lateral acceleration correction submodule is used to determine the corrected lateral acceleration of the vehicle based on the target weighting coefficient, the predicted lateral acceleration of the vehicle, and the actual lateral acceleration.

[0161] Optionally, the target weighted coefficient acquisition submodule includes:

[0162] The initial weighting coefficient acquisition unit is used to acquire the initial weighting coefficients, the variance of the vehicle's actual lateral acceleration, and the rate of change of the vehicle's front wheel steering angle;

[0163] The initial weighting coefficient update unit is used to update the initial weighting coefficients based on the variance of the vehicle's actual lateral acceleration and the rate of change of the vehicle's front wheel steering angle, so as to obtain the target weighting coefficients.

[0164] Optionally, the device further includes:

[0165] The maximum rear wheel steering angle control quantity acquisition module is used to acquire the preset maximum rear wheel steering angle control quantity;

[0166] The data comparison module is used to compare the control value of the target rear wheel steering angle of the vehicle with the control value of the maximum rear wheel steering angle.

[0167] The first data comparison result module is used to take the control value of the maximum rear wheel angle as the control value of the target rear wheel angle if the control value of the target rear wheel angle of the vehicle is greater than the control value of the maximum rear wheel angle.

[0168] The second data comparison result module is used to execute the step of controlling the rear wheels of the vehicle to steer based on the control amount of the target rear wheel steering angle if the control amount of the target rear wheel steering angle of the vehicle is less than or equal to the control amount of the maximum rear wheel steering angle.

[0169] This application also provides an electronic device 80, please refer to... Figure 8 It includes a processor 810 and a memory 820, wherein the memory 810 is used to store computer programs; the processor 820 is used to execute the programs stored in the memory 810 to implement the vehicle rear wheel steering control method described in any embodiment of this application.

[0170] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the vehicle rear-wheel steering control method described in any embodiment of this application.

[0171] In this application, "multiple" refers to two or more.

[0172] In this application, unless otherwise expressly defined, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0173] The terms “first,” “second,” “third,” “fourth,” etc., in this application (if present) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0174] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character "" generally indicates that the preceding and following related objects have an "or" relationship.

[0175] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, if the method includes steps A and B, it means that the method may include steps A and B performed sequentially, or it may include steps B and A performed sequentially. For example, if the method may also include step C, it means that step C may be added to the method in any order. For example, the method may include steps A, B, and C, or it may include steps A, C, and B, or it may include steps C, A, and B, etc.

[0176] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for controlling the rear-wheel steering of a vehicle, characterized in that, The method, applied to a vehicle controller in a vehicle, includes: The vehicle's motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change are obtained. The predicted lateral acceleration of the vehicle is determined based on the vehicle's motion state parameters and steering control parameters. Based on the predicted lateral acceleration and the actual lateral acceleration of the vehicle, the corrected lateral acceleration of the vehicle is determined. The control amount of the target rear wheel steering angle of the vehicle is determined based on the corrected lateral acceleration of the vehicle and the change in the target rear axle lateral compliance. The vehicle's rear wheels are steered according to the control amount of the target rear wheel steering angle.

2. The method according to claim 1, characterized in that, The vehicle's motion parameters include at least one of vehicle speed, lateral acceleration, and yaw rate, and the vehicle's steering control parameters include at least one of front wheel angle and rear wheel angle.

3. The method according to claim 1, characterized in that, The process of obtaining the target rear axle lateral compliance change of the vehicle includes: Obtain the vehicle speed and the corresponding relationship between the preset vehicle speed and the change in rear axle lateral deflection compliance; The target change in rear axle lateral flexibility is determined based on the vehicle speed and the correspondence between the vehicle speed and the change in rear axle lateral flexibility.

4. The method according to claim 1, characterized in that, Determining the predicted lateral acceleration of the vehicle based on its motion state parameters and steering control parameters includes: The vehicle's motion state parameters and steering control parameters are input into a pre-generated vehicle dynamics reference model to obtain the vehicle's predicted lateral acceleration.

5. The method according to claim 1, characterized in that, The step of determining the corrected lateral acceleration of the vehicle based on the predicted lateral acceleration and the actual lateral acceleration includes: Obtain the target weighting coefficient; The corrected lateral acceleration of the vehicle is determined based on the target weighting coefficient, the predicted lateral acceleration of the vehicle, and the actual lateral acceleration.

6. The method according to claim 5, characterized in that, The acquisition of the target weighting coefficient includes: Obtain the initial weighting coefficients, the variance of the actual lateral acceleration of the vehicle, and the rate of change of the front wheel steering angle of the vehicle; The initial weighting coefficients are updated based on the variance of the vehicle's actual lateral acceleration and the rate of change of the vehicle's front wheel steering angle to obtain the target weighting coefficients.

7. The method according to claim 1, characterized in that, After the step of determining the control amount of the target rear wheel steering angle of the vehicle based on the corrected lateral acceleration of the vehicle and the target rear axle lateral compliance change, the method further includes: Obtain the preset maximum rear wheel steering angle control value; The control amount of the target rear wheel steering angle of the vehicle is compared with the control amount of the maximum rear wheel steering angle. If the control amount of the target rear wheel steering angle of the vehicle is greater than the control amount of the maximum rear wheel steering angle, then the control amount of the maximum rear wheel steering angle is taken as the control amount of the target rear wheel steering angle of the vehicle. If the control amount of the target rear wheel steering angle of the vehicle is less than or equal to the control amount of the maximum rear wheel steering angle, then the step of controlling the rear wheels of the vehicle to steer according to the control amount of the target rear wheel steering angle of the vehicle is executed.

8. A vehicle rear-wheel steering control device, characterized in that, The device is used as a vehicle controller in a vehicle and includes: The data acquisition module is used to acquire the vehicle's motion state parameters, steering control parameters, actual lateral acceleration, and target rear axle lateral compliance change. The lateral acceleration prediction module is used to determine the predicted lateral acceleration of the vehicle based on the vehicle's motion state parameters and steering control parameters. The lateral acceleration correction module is used to determine the corrected lateral acceleration of the vehicle based on the predicted lateral acceleration and the actual lateral acceleration of the vehicle. The target rear wheel steering angle control amount determination module is used to determine the control amount of the target rear wheel steering angle of the vehicle based on the corrected lateral acceleration of the vehicle and the change in the target rear axle lateral deflection compliance. The vehicle rear wheel steering control module is used to control the rear wheels of the vehicle to steer according to the control amount of the target rear wheel steering angle.

9. An electronic device, characterized in that, Including processor and memory, among which Memory, used to store computer programs; A processor for executing a program stored in memory to implement the method described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method described in any one of claims 1-7.

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