Steering control method and device of vehicle, computer device and vehicle

Abstract

The application discloses a kind of steering control method, device, computer equipment and vehicle of vehicle, belong to vehicle control field.The method comprises: in the case where vehicle front wheel is steered, the steering parameter of vehicle is collected;Dynamic control parameter of vehicle is determined based on steering parameter;Based on dynamic control parameter, the dynamics model of vehicle is solved, and the target rear wheel rotation angle respectively applicable to high-speed working condition and low-speed working condition is obtained;According to target rear wheel rotation angle, speed interval is set, and rear wheel steering is controlled according to the interval where current vehicle speed is located during vehicle driving.The application fuses the dynamic response characteristics of vehicle at different speeds, and uses dynamic yaw angular velocity and its change rate as control target, compared with traditional static model, has stronger responsiveness and adaptability, can more truly reflect vehicle state, realizes the fine control of rear wheel rotation angle, to simultaneously meet the demand of low-speed maneuverability and high-speed stability.

Description

Technical Field

[0001] This invention belongs to the field of vehicle control, and particularly relates to a vehicle steering control method, device, computer equipment, and vehicle. Background Technology

[0002] With the development of intelligent driving technology, vehicle chassis control systems are gradually evolving from traditional open-loop control to more refined model predictive control. Among them, rear wheel steering (RWS), as a key technology to improve vehicle handling performance and stability under different operating conditions, has received widespread attention.

[0003] In related technologies, rear-wheel steering control often relies on vehicle dynamics models. Based on input conditions such as the vehicle's current speed, front wheel angle, and geometric parameters, the corresponding control quantities are calculated to achieve steering control of the vehicle.

[0004] However, the control results obtained by solving the parameters as the objective at different vehicle speeds and path curvatures may deviate from the true steady state, and the steady-state characteristics of the vehicle often do not meet the driver's control expectations. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the related art. To this end, the present invention proposes a vehicle steering control method, device, computer equipment, and vehicle to balance the flexibility and stability of the rear wheel steering process under different driving conditions.

[0006] In a first aspect, the present invention provides a vehicle steering control method, the method comprising:

[0007] When the front wheels of the vehicle are steer, the vehicle's steering parameters are collected;

[0008] The vehicle's dynamic control parameters are determined based on the steering parameters, including the dynamic center of gravity sideslip angle, dynamic yaw rate, and dynamic yaw rate of change.

[0009] The vehicle's dynamic model is solved based on the dynamic control parameters to obtain the target rear wheel steering angles applicable to high-speed and low-speed conditions, respectively.

[0010] Set the vehicle speed range according to the target rear wheel steering angle, and control the rear wheel steering according to the current vehicle speed range during vehicle operation.

[0011] The vehicle steering control method provided by this invention collects vehicle steering parameters when the front wheels are steering, and determines dynamic control parameters based on these parameters. It uses dynamic centroid sideslip angle, dynamic yaw rate, and dynamic yaw rate of change as control targets, exhibiting stronger responsiveness and adaptability than traditional static models, and more realistically reflecting the vehicle's state. The dynamic control parameters are used to solve the vehicle's dynamic model, yielding target rear wheel angles applicable to both high-speed and low-speed conditions. A partitioned control and fusion strategy for the target rear wheel angles avoids inconsistent vehicle responses caused by sudden changes in rear wheel angle. By setting vehicle speed ranges according to the target rear wheel angles and controlling rear wheel steering based on the current speed range during vehicle operation, dynamic adaptation of the rear wheel angles across different speed ranges is achieved. This improves agility at low speeds and enhances stability at high speeds, improving overall vehicle lateral control performance and ride comfort. Furthermore, the method allows for adjustment of model parameters and control strategies based on different vehicle attributes or specifications, adapting to different vehicle parameters and platforms, and exhibiting strong scalability.

[0012] According to one embodiment of the present invention, determining the dynamic control parameters of the vehicle based on the steering parameters includes:

[0013] Based on the steering parameters, and according to the vehicle's dynamic model, the quasi-static yaw rate and the quasi-static initial center of gravity sideslip angle are determined.

[0014] Based on the quasi-static yaw rate and the quasi-static initial centroid sideslip angle, the dynamic initial yaw rate and the dynamic initial centroid sideslip angle are generated.

[0015] According to the control strategies under high-speed and low-speed conditions, the dynamic initial yaw rate and dynamic initial centroid sideslip angle are corrected to obtain the dynamic centroid sideslip angle and dynamic yaw rate.

[0016] By combining the vehicle's tire lateral force model, and calculating based on the dynamic centroid sideslip angle and dynamic yaw rate, the rate of change of dynamic yaw rate is obtained.

[0017] In the above embodiments, by introducing a solution strategy for dynamic control parameters, based on the current front wheel steering state of the vehicle, the yaw rate, center of gravity sideslip angle and their rate of change are calculated to reflect the dynamic response characteristics of the vehicle, so as to more accurately drive the control of the rear wheel steering angle, ensuring that the vehicle has good steering response and driving stability under different vehicle speeds and operating conditions, and achieving more flexible and stable vehicle handling performance.

[0018] Secondly, the present invention provides a vehicle steering control device, the device comprising:

[0019] The detection module is used to collect the vehicle's steering parameters when the front wheels are turning.

[0020] The calculation module is used to determine the dynamic control parameters of the vehicle based on the steering parameters, the dynamic control parameters including dynamic center of gravity sideslip angle, dynamic yaw rate and dynamic yaw rate of change;

[0021] The calculation module is also used to solve the vehicle's dynamic model based on the dynamic control parameters to obtain the target rear wheel steering angles applicable to high-speed and low-speed conditions, respectively.

[0022] The control module is used to set the vehicle speed range according to the target rear wheel steering angle, and control the rear wheel steering according to the current vehicle speed range during vehicle operation.

[0023] The vehicle steering control device provided by this invention collects vehicle steering parameters when the front wheels are steering, and determines dynamic control parameters based on these parameters. It uses dynamic centroid sideslip angle, dynamic yaw rate, and dynamic yaw rate change rate as control targets, exhibiting stronger responsiveness and adaptability than traditional static models, and more realistically reflecting the vehicle's state. Based on the dynamic control parameters, the device solves the vehicle's dynamic model to obtain target rear wheel angles applicable to both high-speed and low-speed conditions. Through a zoned control and fusion strategy for the target rear wheel angles, it avoids inconsistent vehicle response caused by sudden changes in rear wheel angles. By setting vehicle speed ranges according to the target rear wheel angles and controlling rear wheel steering based on the current speed range during vehicle operation, it achieves dynamic adaptation of the rear wheel angles across different speed ranges. This improves agility at low speeds and enhances stability at high speeds, improving the overall vehicle's lateral control performance and ride comfort. Furthermore, it can adjust model parameters and control strategies based on different vehicle attributes or specifications, adapting to different vehicle parameters and platforms, and exhibiting strong scalability.

[0024] Thirdly, the present invention provides a vehicle for executing and implementing the vehicle steering control method as described in the first aspect.

[0025] Fourthly, the present invention provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the vehicle steering control method as described in the first aspect above.

[0026] Fifthly, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the vehicle steering control method as described in the first aspect above.

[0027] In a sixth aspect, the present invention provides a chip including a processor and a communication interface, the communication interface being coupled to the processor, the processor being used to run computer programs or instructions to implement the vehicle steering control method as described in the first aspect above.

[0028] In a seventh aspect, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the vehicle steering control method as described in the first aspect above.

[0029] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0031] Figure 1 This is a schematic diagram illustrating an application scenario of the vehicle steering control method provided in some embodiments of the present invention;

[0032] Figure 2 This is a schematic flowchart of a vehicle steering control method provided in other embodiments of the present invention;

[0033] Figure 3 This is a schematic diagram of the vehicle steering control device provided in some embodiments of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of a computer device provided in some embodiments of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects, not to describe a particular order or hierarchy.

[0037] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "attachment" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] In this invention, 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 invention, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0040] In this invention, "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0041] In related technologies, rear-wheel steering control methods typically use the sideslip angle or yaw rate as the control target, with some schemes setting the target sideslip angle to zero to approximate steady-state characteristics. However, the sideslip angle is difficult to perceive directly, and its changes do not provide sufficient feedback to the driver's subjective experience. Furthermore, the control results achieved by using this parameter as the target at different vehicle speeds and path curvatures may deviate from the true steady state. To improve the naturalness and controllability of the control effect and to more closely approximate the driver's actual driving intentions, there is an urgent need for a model control method dominated by the target yaw rate and its rate of change, combined with adaptive calculation of the rear wheel steering angle using a vehicle dynamic model, thereby achieving a balanced control of vehicle stability and agility across the entire speed range.

[0042] In view of this, embodiments of the present invention provide a vehicle steering control method, which aims to construct an adaptive rear wheel steering control method based on dynamic control targets. By integrating the dynamic response characteristics of the vehicle at different speeds and using physical quantities such as dynamic yaw rate and its rate of change as control targets, it has stronger responsiveness and adaptability than traditional static models, can more realistically reflect the vehicle state, and achieve fine control of the rear wheel steering angle to simultaneously meet the requirements of low-speed maneuverability and high-speed stability.

[0043] Based on this, the invention proposes a control interval mechanism based on vehicle speed. By setting a transition speed interval and weighting and fusing the target rear wheel angle at different speeds, it avoids discontinuities and abrupt changes in control switching, achieves smooth output of the rear wheel angle, and thus completes a flexible transition of steering control, ensuring driving comfort and safety.

[0044] The vehicle steering control method of this invention is based on a general vehicle dynamics model for control solution. The model has strong adaptability and can be applied to different vehicle models and steering strategies, and has good scalability and practical value.

[0045] It should be noted that the vehicles mentioned in the embodiments of the present invention include, but are not limited to, gasoline vehicles, plug-in hybrid electric vehicles or new energy vehicles, etc., and the present invention does not specifically limit them.

[0046] The vehicle steering control method provided by the present invention will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0047] The vehicle steering control method can be applied to a controller. This controller can be a dedicated vehicle tailgate controller, a microcontroller unit (MCU), or a vehicle control unit (VCU), etc. The following description uses a controller as the executing entity to illustrate the vehicle steering control method provided in this embodiment of the invention.

[0048] Figure 1 This is a schematic flowchart of a vehicle steering control method provided in some embodiments of the present invention. For example... Figure 1 As shown, the vehicle's steering control method includes steps 110 to 140.

[0049] Step 110: When the front wheels of the vehicle are steer, collect the vehicle's steering parameters.

[0050] Front-wheel steering refers to the process of controlling the angle of the front wheels of a vehicle through driver operation or an autonomous driving system, causing the vehicle to turn. Correspondingly, rear-wheel steering refers to the rotation angle of the rear wheels relative to the vehicle's longitudinal axis, used to adjust the vehicle's trajectory and improve handling performance.

[0051] Steering parameters are key parameters used to describe the current steering state of the vehicle, including but not limited to vehicle speed, front wheel angle, etc. These parameters can be used to calculate dynamic control objectives.

[0052] The controller first detects the vehicle's current steering parameters, collecting data including but not limited to the vehicle's current front wheel angle and vehicle speed, as input for subsequent dynamic control calculations.

[0053] For example, the controller can obtain real-time front wheel steering angle, vehicle longitudinal speed, and vehicle body acceleration data collected by acceleration sensors through the vehicle's CAN (Controller Area Network) bus, or collect comprehensive vehicle motion information through IMU (Inertial Measurement Unit).

[0054] Step 120: Determine the vehicle's dynamic control parameters based on the steering parameters. The dynamic control parameters include the dynamic center of gravity sideslip angle, dynamic yaw rate, and dynamic yaw rate of change.

[0055] Dynamic control parameters are key control targets dynamically calculated based on the vehicle's driving state, including dynamic centroid sideslip angle, dynamic yaw rate, and dynamic yaw rate of change, which are used to reflect the vehicle's current and short-term dynamic response requirements.

[0056] After detecting the steering parameters, the controller calculates the dynamic sideslip angle, dynamic yaw rate, and yaw rate change rate in real time based on these parameters to reflect the current dynamic response state of the vehicle. The dynamic sideslip angle, dynamic yaw rate, and yaw rate change rate are all used for subsequent dynamic control calculations, and therefore can be collectively referred to as dynamic control parameters.

[0057] For example, the calculation of dynamic control parameters can be based on a two-degree-of-freedom vehicle model, or by using Kalman filtering to estimate wheel speed sensor data and front wheel steering angle.

[0058] Step 130: Solve the vehicle's dynamic model based on the dynamic control parameters to obtain the target rear wheel steering angles applicable to high-speed and low-speed conditions, respectively.

[0059] A dynamic model is a mathematical model used to describe the dynamic behavior of a vehicle under different control inputs and environmental conditions. Common models include two-degree-of-freedom models, which cover mechanical relationships such as center of mass motion, lateral force, and moment of inertia.

[0060] The high-speed operating condition refers to a condition where the vehicle speed exceeds a preset threshold, and vehicle stability control takes precedence over agility control. Under high-speed conditions, the target rear wheel steering angle focuses on suppressing changes in yaw rate, improving vehicle attitude stability, and preventing sideslip and oversteer. This preset threshold can be determined based on vehicle specifications and test data.

[0061] Low-speed operation refers to a condition where the vehicle speed is below a preset threshold, in which vehicle agility control takes precedence over stability control. Under low-speed conditions, the rear wheels can coordinate with the front wheels for steering, improving vehicle maneuverability on narrow roads or during low-speed U-turns. This preset threshold can be determined based on vehicle specifications and test data.

[0062] Vehicle control requirements differ significantly across different speed ranges. At low speeds, the emphasis is on handling agility, while at high speeds, lateral stability is more important. To adapt to this change, a smooth transition between different speeds is necessary, and the target control parameters should be adjusted based on the vehicle's dynamic response behavior to ensure that the vehicle's steady-state characteristics better match the driver's handling expectations and the vehicle's dynamic characteristics.

[0063] Therefore, based on the calculated dynamic control parameters of the vehicle, the controller substitutes these dynamic control parameters into the two-degree-of-freedom lateral dynamics model of the vehicle, performs analytical calculations within the framework of the two-degree-of-freedom model, and outputs the target rear wheel steering angle applicable to high-speed conditions and the target rear wheel steering angle applicable to low-speed conditions, respectively.

[0064] Step 140: Set the vehicle speed range according to the target rear wheel steering angle, and control the rear wheel steering according to the current vehicle speed range during vehicle operation.

[0065] Based on the target rear wheel steering angles applicable to high-speed and low-speed conditions respectively, the controller can divide the vehicle speed range into low-speed, high-speed, and transitional ranges according to the difference in the target rear wheel steering angle and the vehicle speed characteristic curve, so as to match different rear wheel steering control strategies.

[0066] In the high-speed and low-speed ranges, the controller can directly use the corresponding target rear wheel steering angle to control the vehicle's rear wheel steering. In the transition range, the controller can use a weighted strategy to fuse the target rear wheel steering angles of the high-speed and low-speed conditions, achieving a smooth transition in the rear wheel steering angle output.

[0067] The vehicle steering control method provided in this invention collects vehicle steering parameters when the front wheels are steering, and determines dynamic control parameters based on these parameters. It uses dynamic centroid sideslip angle, dynamic yaw rate, and dynamic yaw rate of change as control targets, exhibiting stronger responsiveness and adaptability than traditional static models, and more realistically reflecting the vehicle's state. The method solves the vehicle's dynamics model based on the dynamic control parameters, obtaining target rear wheel angles applicable to both high-speed and low-speed conditions. A partitioned control and fusion strategy for the target rear wheel angles avoids inconsistent vehicle responses caused by sudden changes in rear wheel angle. By setting vehicle speed ranges according to the target rear wheel angles and controlling rear wheel steering based on the current speed range during vehicle operation, the method achieves dynamic adaptation of the rear wheel angles across different speed ranges. This improves agility at low speeds and enhances stability at high speeds, improving overall lateral control performance and ride comfort. Furthermore, it allows for adjustment of model parameters and control strategies based on different vehicle attributes or specifications, adapting to different vehicle parameters and platforms, and exhibiting strong scalability.

[0068] Because there is a certain lag and inertia in the vehicle response process, the target value calculated by the quasi-static model alone may not be able to effectively reflect the actual driving state. Therefore, it is necessary to introduce a dynamic response modeling method to more realistically approximate the current dynamic characteristics of the vehicle.

[0069] Therefore, in some embodiments, determining the vehicle's dynamic control parameters based on steering parameters includes: determining the quasi-static yaw rate and the quasi-static initial centroid sideslip angle based on the steering parameters and the vehicle's dynamic model; generating the dynamic initial yaw rate and the dynamic initial centroid sideslip angle based on the quasi-static yaw rate and the quasi-static initial centroid sideslip angle; correcting the initial yaw rate and the initial centroid sideslip angle according to control strategies under high-speed and low-speed conditions respectively to obtain the dynamic centroid sideslip angle and the dynamic yaw rate; and calculating the dynamic yaw rate change rate based on the dynamic centroid sideslip angle and the dynamic yaw rate using the vehicle's tire lateral force model.

[0070] The controller, based on the collected vehicle speed and front wheel angle and other steering parameters, combined with the vehicle's structural properties and dynamic model, first determines the vehicle's quasi-static yaw rate and quasi-static initial centroid sideslip angle to characterize the vehicle's steady-state steering response under the current conditions.

[0071] To further consider the dynamic characteristics of the vehicle during the steering process, the controller calculates the initial yaw rate and initial sideslip angle of the vehicle under dynamic conditions based on the quasi-static yaw rate and the quasi-static initial sideslip angle, i.e., the dynamic initial yaw rate and dynamic initial sideslip angle.

[0072] For different vehicle speeds and corresponding control objectives, the initial values ​​are modified according to low-speed and high-speed strategies respectively to obtain dynamic centroid sideslip angle and dynamic yaw rate that can reflect the expected response state of the vehicle.

[0073] Based on the above calculation results, the controller changes the factors used in the calculation process, such as wheelbase, distance from the front and rear axles to the center of gravity, vehicle rotational inertia, or tire curves, to adjust and obtain the final dynamic target yaw angle and dynamic target center of gravity sideslip angle according to the control objectives of improving vehicle agility at low speeds and improving vehicle stability at high speeds.

[0074] For example, the controller can increase the weight of the initial centroid sideslip angle at low speeds to enhance low-speed maneuverability; and at high speeds, it can assign a higher weight to the initial yaw rate to enhance stability at high speeds.

[0075] The calculation of the dynamic yaw rate of change can be based on solving the vehicle's lateral acceleration and angular acceleration using a two-degree-of-freedom model, thereby deriving the required rate of change. Specifically, the controller uses the dynamic center-of-gravity sideslip angle and dynamic yaw rate as inputs into the tire lateral force model, and, combined with the current vehicle state, calculates the rate of change of the dynamic yaw rate, which serves as one of the core indicators for subsequent dynamic control calculations. For example, the tire lateral force model can be a linear lateral force model or a modified linear lateral force model, etc.

[0076] In the above embodiments, by introducing a solution strategy for dynamic control parameters, based on the current front wheel steering state of the vehicle, the yaw rate, center of gravity sideslip angle and their rate of change are calculated to reflect the dynamic response characteristics of the vehicle, so as to more accurately drive the control of the rear wheel steering angle, ensuring that the vehicle has good steering response and driving stability under different vehicle speeds and operating conditions, and achieving more flexible and stable vehicle handling performance.

[0077] In some embodiments, generating dynamic initial yaw rate and dynamic initial centroid sideslip angle based on quasi-static yaw rate and quasi-static initial centroid sideslip angle includes: obtaining dynamic yaw rate and dynamic centroid sideslip angle by introducing dynamic response into quasi-static yaw rate and quasi-static centroid sideslip angle; wherein dynamic response compensation is used to characterize changes in vehicle dynamic characteristics.

[0078] Quasi-static refers to the response characteristics of a vehicle under steady-state or near-steady-state conditions, ignoring the influence of high-speed dynamic changes, and is suitable for calculating the initial target state.

[0079] The controller can model the yaw motion state of the vehicle based on the vehicle's dynamic model and the current steering parameters, and obtain the yaw rate and sideslip angle under quasi-static conditions. On this basis, dynamic response is introduced to correct the above state variables, thereby obtaining the yaw rate and sideslip angle under dynamic conditions.

[0080] Dynamic response refers to the response characteristics of a vehicle under non-steady-state conditions when controlled variables change over time, used to describe dynamic behaviors such as rapid steering or lane changes. Correspondingly, dynamic response compensation is a preset coefficient characterizing the dynamic response characteristics of the vehicle during steering, used to dynamically correct the quasi-static yaw rate and quasi-static center-of-gravity sideslip angle. For example, dynamic response compensation can be determined based on preset compensation parameters to improve the control accuracy of the vehicle under non-steady-state driving conditions. By introducing dynamic response, the actual physical inertia and hysteresis behavior of the vehicle can be reflected, making the calculated dynamic state parameters more consistent with the actual vehicle response, which helps to improve subsequent control accuracy.

[0081] For example, the controller models the vehicle as a two-degree-of-freedom model, using the current vehicle speed and front wheel steering angle as input parameters, and calculates the yaw rate and center-of-gravity sideslip angle under quasi-static conditions based on this model. By introducing dynamic response correction factors, such as those based on the vehicle's moment of inertia, sideslip stiffness, and yaw acceleration trends, the controller can correct the quasi-static parameters to obtain dynamic state values.

[0082] Alternatively, the controller can represent the vehicle's response characteristics to the input using a first-order hysteresis system or a state-space filtering model, thereby dynamically correcting the quasi-static parameters and obtaining the dynamic yaw rate and dynamic centroid sideslip angle.

[0083] For example, the controller calculates the quasi-static target yaw rate and quasi-static target sideslip angle based on the vehicle speed and front wheel steering angle, using a dynamic model. Then, a dynamic response element is added based on the quasi-static target yaw rate and quasi-static target sideslip angle to calculate the vehicle's dynamic target yaw rate and dynamic target sideslip angle using the following formulas:

[0084]

[0085] in, For dynamic yaw rate, β dyn (s) represents the dynamic centroid sideslip angle. Let β be the static yaw rate. stat (s) is the static centroid sideslip angle, T d ω0 is the dynamic response time constant, D is the intrinsic frequency, and T is the damping factor. dω0 and D are calculated based on vehicle speed, vehicle weight, distance from the front and rear axles to the center of gravity, lateral stiffness of the front and rear tires, and vehicle rotational inertia.

[0086] In the above embodiments, by introducing a dynamic response modeling approach, the current dynamic state of the vehicle can be more accurately depicted, improving the timeliness and accuracy of subsequent control commands. Compared with the traditional quasi-static model calculation method, this scheme can effectively adapt to the state changes of the vehicle under different speed and steering conditions, improving the overall vehicle handling performance and control robustness.

[0087] In some embodiments, the dynamic control parameters are used to solve the vehicle's dynamic model to obtain the target rear wheel steering angle applicable to high-speed and low-speed conditions, respectively. This includes: establishing a two-degree-of-freedom model of the vehicle; the two-degree-of-freedom model reflects the lateral force balance relationship and the moment balance relationship around the center of mass of the vehicle; based on the two-degree-of-freedom model, the dynamic target yaw rate, the dynamic target center of mass sideslip angle, and the rate of change of the target yaw rate are substituted into the solution to obtain the target rear wheel steering angle under high-speed conditions; the target rear wheel steering angle under high-speed conditions is converted to obtain the target rear wheel steering angle under low-speed conditions.

[0088] Among them, the two-degree-of-freedom model of a vehicle is a classic vehicle lateral dynamics model, which includes two degrees of freedom: lateral displacement and yaw angle, and is used to calculate dynamic indicators such as yaw rate and sideslip angle.

[0089] The controller constructs a two-degree-of-freedom model of the vehicle, which considers the lateral force balance and the torque balance around the center of mass. Dynamic control parameters (including dynamic yaw rate, dynamic center of mass sideslip angle and yaw rate of change) are substituted into the model, and the target rear wheel steering angle under high-speed conditions is obtained by solving the model.

[0090] Subsequently, the controller corrects the high-speed target rear wheel angle based on the vehicle's steering requirements at low speeds, obtaining a target rear wheel angle suitable for low speeds.

[0091] For example, the controller can convert the target rear wheel steering angle under high-speed conditions into an equivalent front wheel steering angle, or use a trajectory tracking method to obtain the target rear wheel steering angle under low-speed conditions, in order to meet the high flexibility requirements under low-speed conditions.

[0092] In the above embodiments, by solving the target rear wheel steering angles at high speed and low speed respectively, more precise rear wheel control can be achieved under different vehicle speed conditions, improving the dynamic performance of the whole vehicle. The separate calculation and conversion fusion of the high and low speed target angles helps to build a unified rear wheel steering angle control framework and simplify the design of the transition zone control strategy. Among them, the application of the two-degree-of-freedom model takes into account both calculation accuracy and real-time performance, enabling the controller to have good real-time response under actual road conditions.

[0093] In some embodiments, based on a two-degree-of-freedom model, the dynamic target yaw rate, the dynamic target center-of-gravity sideslip angle, and the rate of change of the target yaw rate are substituted into the solution to obtain the target rear wheel steering angle under high-speed conditions. This includes: determining the vehicle's lateral stiffness parameters; the lateral stiffness parameters include the front wheel lateral stiffness and the rear wheel lateral stiffness; using the dynamic target yaw rate, the dynamic target center-of-gravity sideslip angle, and the rate of change of the target yaw rate as target values, and substituting the target values ​​and the lateral stiffness parameters into the two-degree-of-freedom model to solve for the rear wheel steering angle to obtain the target rear wheel steering angle under high-speed conditions.

[0094] Among them, the lateral stiffness parameter represents the lateral force generated by the tire under a unit lateral angle, mainly including the front wheel lateral stiffness and the rear wheel lateral stiffness, which is used to describe the lateral response characteristics of the tire.

[0095] The tire lateral force model is a mathematical model that describes the lateral force generated by the tire under a certain lateral angle. It is used to calculate parameters such as the vehicle's yaw response and center of gravity lateral angle.

[0096] The controller first acquires vehicle structural parameters and tire characteristic data to determine the lateral stiffness of the front and rear wheels. Then, combining the currently detected dynamic target yaw rate, dynamic target center-of-gravity sideslip angle, and target yaw rate of change, it substitutes these target values ​​along with the lateral stiffness parameters into the vehicle's two-degree-of-freedom model. By solving the two-degree-of-freedom problem, the controller can obtain the rear wheel steering angle that satisfies the dynamic performance indicators.

[0097] For example, based on the actual measured vehicle speed, front wheel steering angle, and tire characteristic curves, the controller establishes a two-degree-of-freedom model of the actual vehicle using Newtonian dynamics principles, as follows:

[0098]

[0099]

[0100] Where m is the total vehicle mass and V is the speed of the center of gravity. The rate of change of yaw rate, δ is the rate of change of the centroid sideslip angle, β is the centroid sideslip angle, and δ f For the front wheel steering angle, δ r For the rear wheel steering angle, C f For the front axle lateral stiffness, C r For rear axle lateral stiffness, l f l is the distance from the front axle to the center of gravity. r J is the distance from the rear axle to the center of gravity. z This represents the rotational inertia of the entire vehicle.

[0101] The controller can obtain the front wheel sideslip stiffness Cf and the rear wheel sideslip stiffness Cr through experiments or estimation methods. Based on the above two-degree-of-freedom vehicle model formula, and using dynamic control parameters such as the target yaw rate as constraints, the controller can solve the system of equations to find the rear wheel sideslip angle when the target conditions are met, thereby inferring the rear wheel steering angle.

[0102] In the above embodiments, by introducing front and rear wheel lateral stiffness parameters that reflect the vehicle's tire response characteristics, and using dynamic control parameters as input target values, the accurate calculation of the target rear wheel steering angle under high-speed conditions is achieved, thus providing a theoretical basis for subsequent rear wheel steering control. Compared to calculating the rear wheel angle using only static or simplified models, this solution better ensures the vehicle's lateral stability and path tracking ability at high speeds, contributing to improved vehicle handling and safety.

[0103] The response requirements of a vehicle to rear-wheel steering differ under different vehicle speed conditions: stability is prioritized at high speeds, while maneuverability and agility are emphasized at low speeds. Due to the accuracy limitations of low-speed tire characteristic curves, in order to improve the controllability of low-speed agility control and enhance the explicitness of the function, the control of low-speed rear wheel steering angle can be visualized as the proportional relationship between vehicle speed and front wheel steering angle.

[0104] Therefore, in some embodiments, the target rear wheel steering angle under high-speed conditions is converted to obtain the target rear wheel steering angle under low-speed conditions, including: establishing a proportional mapping relationship between vehicle speed, front wheel steering angle and rear wheel steering angle based on the vehicle speed characteristic curve; and converting the target rear wheel steering angle under high-speed conditions according to the proportional mapping relationship to obtain the target rear wheel steering angle under low-speed conditions.

[0105] Among them, the vehicle speed characteristic curve refers to the function curve that describes the change of vehicle control parameters with vehicle speed, such as the relationship between the rear wheel steering angle or control gain and vehicle speed.

[0106] Based on the calculation of the target rear wheel steering angle under high-speed conditions, the controller needs to further convert this angle into a control target suitable for low-speed conditions. To achieve this conversion, the controller can establish a proportional mapping relationship between vehicle speed, front wheel steering angle, and rear wheel steering angle based on the vehicle speed characteristic curve, and then adjust the target value under high-speed conditions according to this ratio, thereby obtaining a target rear wheel steering angle adapted to low-speed conditions.

[0107] For example, a controller can establish a set of vehicle speed characteristic curves using simulation, experimental, or empirical data to describe the mapping relationship between the front wheel steering angle and the rear wheel steering angle at different vehicle speeds. Typically, as vehicle speed decreases, the rear wheel steering angle will increase relatively in absolute value to improve maneuverability and turning radius control; the mapping relationship will reflect this nonlinear trend.

[0108] In the above embodiments, by establishing a proportional mapping relationship based on vehicle speed characteristics, the rear wheel steering angle under high-speed conditions is accurately converted into the target angle under low-speed conditions. This not only improves the adaptive capability of the control strategy, but also makes the functional objectives of rear wheel steering at different vehicle speeds more targeted: ensuring vehicle stability at high speeds, enhancing vehicle steering flexibility at low speeds, improving overall vehicle handling performance while reducing driver burden.

[0109] In some embodiments, establishing a two-degree-of-freedom model of the vehicle includes: obtaining the vehicle running curve obtained from the test; the vehicle running curve includes at least the vehicle speed characteristic curve, the front wheel steering angle curve, and the tire characteristic curve; and constructing a two-degree-of-freedom model of the vehicle based on the vehicle running curve and dynamic control parameters.

[0110] The controller collects and processes vehicle operation data from actual tests or simulations to obtain vehicle operation curves for modeling. These curves reflect the combined changes of multiple parameters under actual vehicle operating conditions, including vehicle speed characteristic curves, front wheel steering angle curves, and tire characteristic curves. The front wheel steering angle curve represents the change of the front wheel steering angle with time or other state variables (such as vehicle speed), used to simulate or analyze driving input characteristics. The tire characteristic curve characterizes the relationship between physical quantities such as tire lateral force, slip angle, and slip stiffness, used for tire modeling.

[0111] Based on the above curves and the determined dynamic control parameters (dynamic yaw rate, dynamic center of gravity sideslip angle, etc.), a two-degree-of-freedom model of the vehicle is constructed.

[0112] For example, in the specific construction process, the controller can be modeled using experimental data, such as collecting response data from test platforms or real vehicle tests under different vehicle speeds and front wheel steering angle inputs; or, it can be modeled by fitting tire lateral slip characteristics; or, it can determine the center of mass parameters and geometric parameters, such as vehicle mass, center of mass position, wheelbase, track width, moment of inertia, etc., and derive the lateral force balance and moment balance equations to form a complete two-degree-of-freedom motion equation.

[0113] In the above embodiments, the two-degree-of-freedom model constructed based on the vehicle's actual operating curves can more accurately reflect the vehicle's behavioral characteristics under lateral dynamic control, providing an accurate dynamic basis for subsequent rear wheel steering angle calculations. This model is not only applicable to stability control under high-speed conditions but also has adaptability to low-speed conditions, thereby significantly improving the reliability, applicability, and accuracy of the control strategy.

[0114] In some embodiments, setting a vehicle speed range according to a target rear wheel steering angle and controlling the vehicle's rear wheel steering in different speed ranges includes: setting a vehicle speed range according to a target rear wheel steering angle; the speed range includes at least a low-speed range, a high-speed range, and a transition range; detecting the vehicle's current speed and determining the vehicle's current speed range based on the current speed; when the vehicle is currently in the low-speed range, controlling the vehicle's rear wheel steering according to the rear wheel steering angle corresponding to the low-speed range; when the vehicle is currently in the high-speed range, controlling the vehicle's rear wheel steering according to the rear wheel steering angle corresponding to the high-speed range; when the vehicle is currently in the transition range, performing weight allocation based on the current vehicle speed, and fusing the target rear wheel steering angles under high-speed and low-speed conditions to obtain a rear wheel steering angle for smooth transition.

[0115] The transition range refers to the speed range in which a vehicle transitions from a low speed to a high speed or vice versa, and is used to achieve a smooth switching of control strategies.

[0116] Smooth transition refers to the continuity and stability of control variables or control strategies during the process of change, avoiding sudden changes or oscillations.

[0117] The controller establishes control logic related to vehicle speed based on the target rear wheel steering angle obtained under high-speed and low-speed conditions, divides the vehicle speed range into low-speed range, high-speed range and transition range, and determines the vehicle speed range it is in based on the vehicle's current real-time speed value.

[0118] For example, speeds less than V1 (e.g., 30 km / h) are defined as the low-speed range, speeds greater than V2 (e.g., 70 km / h) are defined as the high-speed range, and the area in between is a transition range. The controller can determine in real time which range the current vehicle speed belongs to by reading the output of the onboard speed sensor.

[0119] Based on the control strategy for different ranges, the controller determines the actual rear wheel steering angle for the application.

[0120] When the vehicle is currently in a low-speed range, the controller controls the rear wheel steering according to the rear wheel steering angle corresponding to the low-speed range.

[0121] When the vehicle is currently in a high-speed range, the controller controls the rear wheel steering according to the rear wheel steering angle corresponding to the high-speed range.

[0122] When the vehicle is currently in the transition zone, the controller assigns weights based on the current vehicle speed and fuses the target rear wheel steering angles under high-speed and low-speed conditions to obtain a rear wheel steering angle for smooth transition. For example, the controller can set a weighting factor α that varies with vehicle speed and fuse the target rear wheel steering angles under high-speed and low-speed conditions through linear interpolation to obtain the final target rear wheel steering angle. The fused rear wheel steering angle command is then sent to the rear wheel steering actuator to control the vehicle's rear wheel steering, thereby achieving a smooth transition.

[0123] The division of vehicle speed ranges and weighting factors can be customized according to different vehicle models and control requirements, demonstrating good scalability.

[0124] In the above embodiments, by improving steering flexibility and ease of operation at low speeds, enhancing vehicle yaw stability and response consistency at high speeds, and achieving a smooth transition between the two control strategies in the transition range, sudden changes in vehicle response or jumps in control logic are avoided, thereby improving driving comfort and safety.

[0125] In some embodiments, when the vehicle is currently in a transition zone, the target rear wheel steering angles under high-speed and low-speed conditions are fused based on the current vehicle speed to obtain a rear wheel steering angle for smooth transition. This includes: when the vehicle is in a transition zone, determining the weight factors corresponding to high-speed and low-speed conditions respectively based on the current vehicle speed; and performing weighted fusion of the target rear wheel steering angles under high-speed and low-speed conditions based on the weight factors corresponding to high-speed and low-speed conditions to obtain a rear wheel steering angle for smooth transition.

[0126] The weighting factor is a coefficient used when weighting and fusing multiple control targets, and is used to dynamically adjust the contribution ratio of the targets based on factors such as the current vehicle speed.

[0127] After detecting that the vehicle is currently in the transition speed range, the controller calculates the weighting factors of low-speed and high-speed conditions based on the current vehicle speed, and then uses these factors to weight the target rear wheel steering angle under the two conditions to generate a fused rear wheel steering angle command.

[0128] For example, weighting factors can be set for high-speed and low-speed operating conditions respectively, and then fused using methods such as linear interpolation and weighted averaging. For instance, if the high-speed operating condition corresponds to weighting factor α and the low-speed operating condition corresponds to weighting factor β, then the rear wheel steering angle used for smooth transition = weighting factor α * rear wheel steering angle corresponding to high-speed operating condition + weighting factor β * rear wheel steering angle corresponding to low-speed operating condition, and so on.

[0129] For example, the controller can set a fusion buffer or differential limit to avoid frequent switching or over-response.

[0130] In the above embodiments, a speed-based weight allocation mechanism is used to achieve dynamic fusion between the target rear wheel angles at high and low speeds. This avoids steering jitter or instability caused by sudden changes in control strategy when the vehicle enters the transition zone, improves the steering continuity and response smoothness of the whole vehicle, and can adapt to the comprehensive needs of dynamic stability and comfort under different vehicle models and driving conditions.

[0131] In some embodiments, based on the current vehicle speed, the weighting factors corresponding to high-speed and low-speed operating conditions are determined respectively, including: obtaining vehicle attribute information; determining a control strategy under the transition range based on the attribute information, the control strategy including a flexibility strategy and a stability strategy; and adjusting the initial weighting factors under the determined control strategy to obtain the weighting factors corresponding to high-speed and low-speed operating conditions respectively.

[0132] The vehicle's attribute information includes, but is not limited to, the vehicle model and its body parameters. Body parameters describe the vehicle's physical characteristics and structural parameters, including but not limited to vehicle weight, front and rear wheel load distribution, wheelbase, track width, steering response sensitivity, and suspension stiffness.

[0133] A control strategy refers to the rules that determine how to set the rear wheel steering angle or other control variables under specific vehicle attribute information. It usually relies on dynamic models and objective function design.

[0134] Control strategies include flexibility strategies and stability strategies. Flexibility strategies aim to improve low-speed handling and responsiveness, and are suitable for narrow roads or low-speed cornering scenarios. Stability strategies aim to improve vehicle stability and anti-skid capabilities at high speeds, and are suitable for high-speed cruising, emergency obstacle avoidance, and other similar scenarios.

[0135] For example, if the vehicle is a sports vehicle, the goal during steering is to improve agility, or to prioritize agility. Therefore, the control strategy is a flexibility strategy, and the handling methods in the mid-speed range or transition range are similar to or the same as those in the high-speed range.

[0136] For example, if the vehicle is a commercial vehicle, the goal during steering is to improve stability, or to prioritize stability. Therefore, the control strategy is a stability strategy, and the handling methods in the mid-speed range or transition range are similar to or the same as those in the low-speed range.

[0137] Therefore, based on the determined control strategy, the controller can adjust the initial weighting factor to obtain the weighting factors corresponding to high-speed and low-speed operating conditions respectively.

[0138] For example, the initial weights are the weights corresponding to high-speed and low-speed operating conditions. When the control strategy is a flexibility strategy, the controller can assign a higher fusion weight to the rear wheel angle of the high-speed target. For example, the controller can increase the weight factor corresponding to the high-speed operating condition and decrease or keep the weight factor corresponding to the low-speed operating condition unchanged. Alternatively, when the control strategy is a stability strategy, the controller can assign a higher fusion weight to the rear wheel angle of the low-speed target. For example, the controller can increase the weight factor corresponding to the low-speed operating condition and decrease or keep the weight factor corresponding to the high-speed operating condition unchanged, and so on.

[0139] The initial weights can be obtained based on linear interpolation, logical lookup tables, or neural network prediction. Adjustments to the fusion weight factors can be made through functional relationships to achieve smooth weight changes.

[0140] In the above embodiments, by introducing vehicle attribute information and selecting different control strategies in combination with actual needs, the fusion ratio of the target rear wheel angle at high speed and low speed can be set more reasonably. Combined with different control objectives (such as handling flexibility or stability), different fusion weights are assigned to the target rear wheel angle under high speed and low speed conditions, so as to realize the adaptive optimization adjustment of the rear wheel angle in the transition range. Compared with static weight setting or linear interpolation method, it can more finely balance handling flexibility and stability, and improve the overall vehicle handling performance, response consistency and driving comfort.

[0141] Figure 2 This is a schematic flowchart of vehicle steering control provided in other embodiments of the present invention. For example... Figure 2 As shown, the method includes steps 1 through 8. Wherein:

[0142] Step 1: Based on the vehicle speed and the external input of the front wheel steering angle, calculate the quasi-static target yaw rate and the quasi-static target center of mass sideslip angle according to the dynamic model;

[0143] Step 2: Based on the quasi-static target yaw rate and the quasi-static target centroid sideslip angle, add a dynamic response component to calculate the vehicle dynamic target yaw rate and the vehicle dynamic target centroid sideslip angle;

[0144] Step 3: Based on the above calculation results, change the factors used in the calculation process, such as wheelbase, distance from the front and rear axles to the center of gravity, vehicle rotational inertia, or tire curves, and adjust them according to the control objectives of improving vehicle agility at low speeds and improving vehicle stability at high speeds to obtain the final dynamic target yaw angle and dynamic target center of gravity sideslip angle.

[0145] Step 4: Based on the target yaw rate and target center of mass sideslip angle calculated above, use the front and rear axle tire formula to calculate the rate of change of the target yaw rate;

[0146] Step 5: Based on the actual measured vehicle speed, front wheel angle, and tire characteristic curve, establish a two-degree-of-freedom model of the actual vehicle using the principles of Newtonian dynamics.

[0147] Step 6: Calculate the real-time lateral stiffness of the front and rear axles using the two-degree-of-freedom model from Step 5, and based on the target yaw rate calculated in Step 3 and the rate of change of the target yaw rate calculated in Step 4, as well as the current actual front wheel steering angle and center of gravity speed, calculate the target rear wheel steering angle according to the vehicle's two-degree-of-freedom model.

[0148] Step 7: Based on the results of Step 6, due to the accuracy problem of the low-speed tire characteristic curve, in order to improve the controllability of low-speed agility control and enhance the explicitness of the function, the control of the low-speed rear wheel steering angle can be visualized as the ratio between vehicle speed and front wheel steering angle, and the target rear wheel steering angle under low-speed conditions can be obtained based on the ratio.

[0149] Step 8: Based on the rear wheel steering angle obtained in Step 6 for high-speed conditions and the rear wheel steering angle obtained in Step 7 for low-speed conditions, plan the speed range for angle transition, and perform weighting based on the speed factor according to the speed change to achieve a smooth transition between high and low speed angle control. For details, please refer to the calibration results.

[0150] The vehicle steering control method provided by this invention calculates the target rear wheel steering angle based on the target yaw rate. The calculation of the target yaw rate is based on variable vehicle parameters (including vehicle wheelbase, vehicle moment of inertia, tire characteristic curves, etc.). The method calculates the target yaw rate change rate and the target center of gravity sideslip angle based on the variable vehicle parameters. It can flexibly adjust the control target on the algorithm according to the ideal control result, improve the flexibility of control, and enhance the driver's on-loop experience and perception during the development process, thereby improving the accuracy of control.

[0151] Compared to traditional solutions, this invention is based on model-based control. When calculating the rear wheel steering angle control angle, it uses the target yaw rate as the primary vehicle control target. This control target clearly reflects the driver-perceptible yaw rate gain (yaw rate of change / front wheel steering angle), accurately yielding the final overall vehicle steady-state characteristics. Furthermore, by employing a control method with adjustable parameters based on the target yaw rate (including vehicle wheelbase, vehicle moment of inertia, tire characteristic curves, etc.), it can create a control target close to the real steady-state vehicle, avoiding the potential for non-absolute steady-state vehicle control results caused by using a target centroid sideslip angle of zero. This model control based on the target yaw rate of change improves the controllability of the control process and the accuracy of the control results, resulting in a more natural control effect without producing strange vehicle perceptions. Based on model control, low-speed control is visualized as a proportional relationship, enhancing the explicitness and accuracy of low-speed control effects. Based on this, a transition algorithm for high and low-speed control is designed to improve the continuity of rear wheel steering control across the entire vehicle speed range. The rear-wheel steering control system based on this control method can comprehensively improve the agility of low-speed vehicles under steady-state conditions and reduce the turning radius; improve the stability of high-speed vehicles and make lane changes smoother; while in the mid-speed range, it can be flexibly configured according to the characteristics of the vehicle model to either improve agility or improve stability, ultimately changing the driving characteristics of the vehicle in steady-state conditions across the entire speed range.

[0152] The vehicle steering control method provided in this embodiment of the invention can be executed by a vehicle steering control device. This embodiment of the invention uses the vehicle steering control device executing the vehicle steering control method as an example to illustrate the vehicle steering control device provided in this embodiment of the invention.

[0153] This invention also provides a vehicle steering control device applied to a computer device. The computer device may be, for example, a controller or a control system.

[0154] Figure 3 This is a schematic diagram of the structure of a computer device provided in some embodiments of the present invention. For example... Figure 3 As shown, the vehicle's steering control device includes a detection module 301, a calculation module 302, and a control module 303. Wherein:

[0155] The detection module 301 is used to collect the vehicle's steering parameters when the front wheels are turning.

[0156] The calculation module 302 is used to determine the dynamic control parameters of the vehicle based on the steering parameters. The dynamic control parameters include the dynamic center of gravity sideslip angle, the dynamic yaw rate, and the rate of change of the dynamic yaw rate.

[0157] The calculation module 302 is also used to solve the vehicle's dynamic model based on dynamic control parameters to obtain the target rear wheel steering angles applicable to high-speed and low-speed conditions, respectively.

[0158] The control module 303 is used to set the vehicle speed range according to the target rear wheel turning angle, and to control the rear wheel steering according to the current vehicle speed range during vehicle operation.

[0159] The vehicle steering control device provided in this embodiment of the invention, through a vehicle steering control method, collects vehicle steering parameters when the front wheels are steering, and determines dynamic control parameters of the vehicle based on the steering parameters. It uses dynamic centroid sideslip angle, dynamic yaw rate, and dynamic yaw rate change rate as control targets, exhibiting stronger responsiveness and adaptability than traditional static models, and more realistically reflecting the vehicle state. Based on the dynamic control parameters, the vehicle's dynamic model is solved to obtain target rear wheel steering angles applicable to high-speed and low-speed conditions respectively. Through a partitioned control and fusion strategy of the target rear wheel steering angle, inconsistent vehicle response caused by sudden changes in rear wheel steering angle is avoided. A vehicle speed range is set according to the target rear wheel steering angle, and the rear wheel steering is controlled according to the current speed range during vehicle operation. This achieves dynamic adaptation of the rear wheel steering angle in different speed ranges, improving agility at low speeds and enhancing stability at high speeds, thereby improving the overall lateral control performance and ride comfort of the vehicle. Furthermore, it can adjust model parameters and control strategies based on different vehicle attributes or specifications, adapting to different vehicle parameters and platforms, and exhibiting strong scalability.

[0160] According to one embodiment of the present invention, the calculation module is further configured to determine the quasi-static yaw rate and the quasi-static initial centroid sideslip angle based on the steering parameters and the vehicle's dynamic model; generate the dynamic initial yaw rate and the dynamic initial centroid sideslip angle based on the quasi-static yaw rate and the quasi-static initial centroid sideslip angle; correct the initial yaw rate and the initial centroid sideslip angle according to the control strategies under high-speed and low-speed conditions respectively to obtain the dynamic centroid sideslip angle and the dynamic yaw rate; and calculate the dynamic yaw rate change rate based on the dynamic centroid sideslip angle and the dynamic yaw rate in conjunction with the vehicle's tire lateral force model.

[0161] According to one embodiment of the present invention, the calculation module is further configured to obtain the dynamic yaw rate and the dynamic center of gravity sideslip angle by introducing dynamic response compensation into the quasi-static yaw rate and the quasi-static center of gravity sideslip angle; wherein the dynamic response compensation is a preset coefficient characterizing the dynamic response characteristics of the vehicle during steering, used to dynamically correct the quasi-static yaw rate and the quasi-static center of gravity sideslip angle.

[0162] According to one embodiment of the present invention, the calculation module is further used to establish a two-degree-of-freedom model of the vehicle; the two-degree-of-freedom model reflects the lateral force balance relationship and the moment balance relationship around the center of mass of the vehicle; based on the two-degree-of-freedom model, the dynamic target yaw rate, the dynamic target center of mass sideslip angle and the target yaw rate change rate are substituted into the solution to obtain the target rear wheel rotation angle under high-speed conditions; the target rear wheel rotation angle under high-speed conditions is converted to obtain the target rear wheel rotation angle under low-speed conditions.

[0163] According to one embodiment of the present invention, the calculation module is further used to determine the lateral stiffness parameters of the vehicle; the lateral stiffness parameters include the front wheel lateral stiffness and the rear wheel lateral stiffness; the dynamic target yaw rate, the dynamic target center of mass lateral angle and the target yaw rate change rate are used as target values, and the target values ​​and the lateral stiffness parameters are substituted into a two-degree-of-freedom model to solve for the rear wheel steering angle, thereby obtaining the target rear wheel steering angle under high-speed conditions.

[0164] According to one embodiment of the present invention, the calculation module is further configured to establish a proportional mapping relationship between vehicle speed, front wheel steering angle and rear wheel steering angle based on the vehicle speed characteristic curve; and to convert the target rear wheel steering angle under high-speed conditions to obtain the target rear wheel steering angle under low-speed conditions based on the proportional mapping relationship.

[0165] According to one embodiment of the present invention, the calculation module is further used to obtain the vehicle running curve obtained from the test; the vehicle running curve includes at least the vehicle speed characteristic curve, the front wheel steering angle curve and the tire characteristic curve; based on the vehicle running curve and dynamic control parameters, a two-degree-of-freedom model of the vehicle is constructed.

[0166] According to one embodiment of the present invention, the control module is further configured to set a vehicle speed range according to a target rear wheel steering angle; the vehicle speed range includes at least a low speed range, a high speed range, and a transition range; detect the current vehicle speed and determine the current vehicle speed range based on the current vehicle speed; when the vehicle is currently in the low speed range, control the rear wheel steering of the vehicle according to the rear wheel steering angle corresponding to the low speed range; when the vehicle is currently in the high speed range, control the rear wheel steering of the vehicle according to the rear wheel steering angle corresponding to the high speed range; when the vehicle is currently in the transition range, perform weight allocation according to the current vehicle speed, and fuse the target rear wheel steering angles under the high speed condition and the low speed condition to obtain a rear wheel steering angle for smooth transition.

[0167] According to one embodiment of the present invention, the control module is further configured to, when the vehicle is in the transition zone, determine the weighting factors corresponding to the high-speed condition and the low-speed condition respectively based on the current vehicle speed; and, based on the weighting factors corresponding to the high-speed condition and the low-speed condition respectively, perform weighted fusion of the target rear wheel steering angle under the high-speed condition and the low-speed condition to obtain the rear wheel steering angle for smooth transition.

[0168] According to one embodiment of the present invention, the control module is further configured to acquire vehicle attribute information; determine a control strategy under the transition interval based on the attribute information, the control strategy including a flexibility strategy and a stability strategy; and adjust the initial weighting factor under the determined control strategy to obtain the weighting factors corresponding to the high-speed condition and the low-speed condition respectively.

[0169] The vehicle steering control device in this embodiment of the invention can be a computer device or a component within the computer device, such as an integrated circuit or a chip. The computer device can be a controller. Exemplary examples include mobile phones, tablets, laptops, handheld computers, in-vehicle computer devices, mobile internet devices (MIDs), augmented reality (AR) / virtual reality (VR) devices, robots, wearable devices, ultra-mobile personal computers (UMPCs), netbooks, or personal digital assistants (PDAs), etc. It can also be a server, network attached storage (NAS), a personal computer (PC), a television set (TV), an ATM, or a self-service machine, etc. This embodiment of the invention does not impose specific limitations.

[0170] This invention also provides a vehicle for executing and implementing the above-described vehicle steering control method.

[0171] This invention also provides a vehicle, the vehicle comprising as follows: Figure 3 The vehicle shown has a steering control system.

[0172] The vehicle steering control device in this embodiment of the invention can be a device with an operating system. This operating system can be a Microsoft (Windows) operating system, an Android operating system, an iOS operating system, or other possible operating systems; this embodiment of the invention does not impose specific limitations.

[0173] The vehicle steering control device provided in this embodiment of the invention can realize the various processes implemented in the various method embodiments, and will not be described again here to avoid repetition.

[0174] Figure 4 This is a schematic diagram of the structure of a computer device provided in some embodiments of the present invention. In some embodiments, such as... Figure 4As shown, this embodiment of the invention also provides a computer device 400, including a processor 401, a memory 402, and a computer program stored in the memory 402 and executable on the processor 401. When the program is executed by the processor 401, it implements the various processes of the above-described method embodiments and achieves the same technical effects. To avoid repetition, it will not be described again here.

[0175] It should be noted that the computer device in the embodiments of the present invention includes the mobile computer device and the non-mobile computer device described above.

[0176] This invention also provides a non-transitory computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the various processes of the above-described vehicle steering control method embodiments and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0177] The processor is the processor in the computer device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0178] This invention also provides a computer program product, including a computer program that, when executed by a processor, implements the aforementioned vehicle steering control method.

[0179] The processor is the processor in the computer device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0180] This invention also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described vehicle steering control method embodiments and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0181] It should be understood that the chip mentioned in the embodiments of the present invention may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0182] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0183] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the related technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0184] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

[0185] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0186] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0187] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0188] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates 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.

[0189] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vehicle steering control method, characterized in that, The method includes: When the front wheels of the vehicle are steer, the vehicle's steering parameters are collected; The vehicle's dynamic control parameters are determined based on the steering parameters, including the dynamic center of gravity sideslip angle, dynamic yaw rate, and dynamic yaw rate of change. The vehicle's dynamic model is solved based on the dynamic control parameters to obtain the target rear wheel steering angles applicable to high-speed and low-speed conditions, respectively. Set the vehicle speed range according to the target rear wheel steering angle, and control the rear wheel steering according to the current vehicle speed range during vehicle operation; The process of solving the vehicle's dynamic model based on the dynamic control parameters to obtain target rear wheel steering angles applicable to both high-speed and low-speed conditions includes: A two-degree-of-freedom model of the vehicle is established; the two-degree-of-freedom model reflects the lateral force balance relationship and the moment balance relationship around the center of mass of the vehicle. Based on the two-degree-of-freedom model, the dynamic target yaw rate, the dynamic target center of mass sideslip angle and the target yaw rate change rate are substituted into the solution to obtain the target rear wheel rotation angle under high-speed conditions. The target rear wheel steering angle under high-speed conditions is converted to obtain the target rear wheel steering angle under low-speed conditions; Based on the two-degree-of-freedom model, the dynamic target yaw rate, the dynamic target center-of-gravity sideslip angle, and the rate of change of the target yaw rate are substituted into the solution to obtain the target rear wheel steering angle under high-speed conditions, including: Determine the vehicle's lateral stiffness parameters; the lateral stiffness parameters include the front wheel lateral stiffness and the rear wheel lateral stiffness; The dynamic target yaw rate, the dynamic target center of mass sideslip angle, and the rate of change of the target yaw rate are used as target values. The target values ​​and sideslip stiffness parameters are substituted into the two-degree-of-freedom model to solve for the rear wheel steering angle, thus obtaining the target rear wheel steering angle under high-speed conditions.

2. The method according to claim 1, characterized in that, The process of determining the vehicle's dynamic control parameters based on the steering parameters includes: Based on the steering parameters, and according to the vehicle's dynamic model, the quasi-static yaw rate and the quasi-static initial center of gravity sideslip angle are determined. Based on the quasi-static yaw rate and the quasi-static initial centroid sideslip angle, the dynamic initial yaw rate and the dynamic initial centroid sideslip angle are generated. According to the control strategies under high-speed and low-speed conditions, the dynamic initial yaw rate and dynamic initial centroid sideslip angle are corrected to obtain the dynamic centroid sideslip angle and dynamic yaw rate. By combining the vehicle's tire lateral force model, and calculating based on the dynamic centroid sideslip angle and dynamic yaw rate, the rate of change of dynamic yaw rate is obtained.

3. The method according to claim 2, characterized in that, The process of generating dynamic initial yaw rate and dynamic initial sideslip angle based on the quasi-static yaw rate and quasi-static initial sideslip angle includes: By introducing dynamic response compensation into the quasi-static yaw rate and quasi-static centroid sideslip angle, the dynamic initial yaw rate and dynamic initial centroid sideslip angle are obtained. The dynamic response compensation is a preset coefficient that characterizes the dynamic response characteristics of a vehicle during steering, and is used to dynamically correct the quasi-static yaw rate and the quasi-static center of gravity sideslip angle.

4. The method according to claim 1, characterized in that, The conversion of the target rear wheel steering angle under high-speed conditions to obtain the target rear wheel steering angle under low-speed conditions includes: Based on the vehicle speed characteristic curve, establish the proportional mapping relationship between vehicle speed, front wheel steering angle and rear wheel steering angle; Based on the proportional mapping relationship, the target rear wheel steering angle under high-speed conditions is converted to obtain the target rear wheel steering angle under low-speed conditions.

5. The method according to any one of claims 1 or 4, characterized in that, The establishment of the two-degree-of-freedom model of the vehicle includes: Obtain the vehicle operating curve obtained from the test; the vehicle operating curve includes at least the vehicle speed characteristic curve, the front wheel steering angle curve, and the tire characteristic curve. A two-degree-of-freedom model of the vehicle is constructed based on the vehicle's operating curve and dynamic control parameters.

6. The method according to claim 1, characterized in that, The step of setting a vehicle speed range according to the target rear wheel steering angle and controlling the vehicle's rear wheel steering in different speed ranges includes: The vehicle speed range is set according to the target rear wheel steering angle; the vehicle speed range includes at least a low speed range, a high speed range, and a transition range; Detect the vehicle's current speed and determine the vehicle's current speed range based on the current speed; When the vehicle is currently in a low-speed range, the rear wheel steering is controlled according to the rear wheel steering angle corresponding to the low-speed range. When the vehicle is currently in a high-speed range, the rear wheel steering is controlled according to the rear wheel steering angle corresponding to the high-speed range. When the vehicle is currently in the transition zone, the target rear wheel steering angles under high-speed and low-speed conditions are fused based on the current vehicle speed to obtain the rear wheel steering angle used for smooth transition.

7. The method according to claim 6, characterized in that, When the vehicle is currently in the transition zone, a weighted allocation is performed based on the current vehicle speed, and the target rear wheel steering angles under high-speed and low-speed conditions are fused to obtain the rear wheel steering angle used for smooth transition, including: When the vehicle is in the transition zone, the weighting factors corresponding to the high-speed condition and the low-speed condition are determined respectively based on the current vehicle speed. Based on the weighting factors corresponding to high-speed and low-speed operating conditions, the target rear wheel steering angles under high-speed and low-speed operating conditions are weighted and fused to obtain the rear wheel steering angles used for smooth transition.

8. The method according to claim 7, characterized in that, The determination of weighting factors for high-speed and low-speed operating conditions based on the current vehicle speed includes: Obtain vehicle attribute information; The control strategy under the transition range is determined based on attribute information, and the control strategy includes a flexibility strategy and a stability strategy. Under the determined control strategy, the initial weighting factors are adjusted to obtain the corresponding weighting factors for high-speed and low-speed operating conditions.

9. A vehicle steering control device, characterized in that, The apparatus for implementing the method as described in any one of claims 1-8 comprises: The detection module is used to collect the vehicle's steering parameters when the front wheels are turning. The calculation module is used to determine the dynamic control parameters of the vehicle based on the steering parameters, the dynamic control parameters including dynamic center of gravity sideslip angle, dynamic yaw rate and dynamic yaw rate of change; The calculation module is also used to solve the vehicle's dynamic model based on the dynamic control parameters to obtain the target rear wheel steering angles applicable to high-speed and low-speed conditions, respectively. The control module is used to set the vehicle speed range according to the target rear wheel steering angle, and control the rear wheel steering according to the current vehicle speed range during vehicle operation.

10. A vehicle, characterized in that, The vehicle is used to execute and implement the steering control method of the vehicle as described in any one of claims 1-8.

11. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the vehicle steering control method as described in any one of claims 1-8.

Images