Vehicle stability control method and system based on rear wheel steering

Abstract

The invention provides a vehicle stability control method and system based on rear wheel steering, and belongs to the technical field of automobile safety, and the vehicle stability control method based on rear wheel steering comprises the steps that A, real-time monitoring and instability judgment are conducted on the vehicle state; a vehicle dynamics model is constructed through sensor data, and the deviation delta gamma between the actual yaw velocity gamma < actual > and the ideal yaw velocity gamma < target > is calculated; if the delta gamma exceeds a threshold value or the lateral force of the tire is saturated, judging that the vehicle enters an unstable state; and B, rear wheel steering-braking cooperative control is adopted. By the adoption of the method, the dynamic stability control capacity and safety of the vehicle body can be effectively improved by actively adjusting the steering angle of the rear wheels of the vehicle.

Description

Technical Field

[0001] This invention relates to automotive safety technology, and in particular to a vehicle stability control method and system based on rear-wheel steering (Active Kinematic Control, AKC). Background Technology

[0002] Existing Vehicle Stability Control (VSC) is a dynamic safety system that actively intervenes in the vehicle's operation using electronic technology through Electronic Stability Control (ESC) or Electronic Stability Program (ESP) to improve handling stability and prevent loss of control. Its working principle is as follows: multiple sensors continuously collect vehicle status data, including: wheel speed sensors monitoring the rotational speed of each wheel, steering angle sensors recording the steering wheel angle, lateral acceleration sensors detecting lateral forces, and yaw rate sensors measuring the vehicle's rotational speed around its vertical axis (e.g., oversteer or understeer). The electronic control unit (ECU) then compares the real-time data with a preset model (e.g., the driver's expected path) to determine if slippage, sideslip, or deviation from the trajectory has occurred, and actively intervenes.

[0003] However, existing VSC systems have the following defects or shortcomings, mainly: 1) Sensor limitations: The system's sensors rely too heavily on data such as wheel speed, steering angle, and yaw rate. If the sensors are contaminated (e.g., by snow or mud) or malfunction (e.g., by electromagnetic interference), it may lead to misjudgments of the vehicle's status; 2) Latency issues: Due to millisecond-level delays in sensor data acquisition and processing, real-time responses may be impossible in extreme dynamic scenarios (e.g., high-speed emergency obstacle avoidance); 3) Performance degradation under extreme conditions: For example, when the vehicle is driving on low-friction surfaces such as ice, snow, or sand, the system may intervene excessively due to tire slippage (e.g., frequent braking), resulting in decreased handling; 4) Issues with extreme cornering or aggressive driving: For example, when the vehicle approaches its physical limits (e.g., drifting), the system may forcibly intervene in power output or braking, disrupting the driver's intentions, especially on racetracks or in off-road scenarios, requiring manual deactivation of the VSC system. Therefore, further improvements are urgently needed to address the aforementioned technical defects or shortcomings of existing VSC systems. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art, and proposes a vehicle stability control method and system based on rear wheel steering, which improves vehicle dynamic control capability and safety by actively adjusting the rear wheel steering angle.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, embodiments of the present invention provide a vehicle stability control method based on rear-wheel steering, comprising:

[0007] A. Steps for real-time monitoring and instability determination of vehicle status; construct a vehicle dynamics model through sensor data, and calculate the deviation Δγ between the actual yaw rate γ_actual and the ideal yaw rate γ_target; if Δγ exceeds the threshold or the tire lateral force is saturated, the vehicle is determined to have entered an unstable state.

[0008] B. The steps for adopting the corresponding rear-wheel steering-braking coordinated control method for different vehicle instability states.

[0009] Preferably, step B is followed by:

[0010] C. Steps for torque coordination and smooth transition: Reduce drive wheel torque through the powertrain while ensuring a smooth change in the rear wheel steering angle to avoid driving shock.

[0011] Wherein: the vehicle instability state described in step A includes decreased yaw stability and decreased lateral stability.

[0012] Step B, which describes the control steps involving rear-wheel steering and braking coordination, includes:

[0013] For understeer scenarios, control the rear wheels to rotate in the same direction as the front wheels or rotate in opposite directions at a small angle to increase the yaw moment of the whole vehicle; or apply braking force to the inner rear wheel to suppress the understeer effect.

[0014] In cases of oversteer, the rear wheels can be quickly reversed to counteract the tendency of the rear to sideslip; or the outer front wheels can be braked to help restore the vehicle's posture.

[0015] Preferably, the control steps employing rear-wheel steering-braking coordination described in step B further include:

[0016] The steps for controlling weight allocation involve dynamically adjusting the contribution ratio of rear wheel steering and braking based on the road surface adhesion coefficient and vehicle speed.

[0017] The vehicle stability control algorithm specifically used in step B includes:

[0018] (1) The desired yaw rate is calculated using the following formula:

[0019] Where: L is the wheelbase, K is the stability factor, and δ front The steering angle of the front wheels;

[0020] (2) The yaw rate feedback control quantity is calculated using the following formula:

[0021] ;

[0022] Where: based on the actual yaw rate γ real With γ des To account for the deviation, design a proportional-integral-derivative PID controller; the output rear wheel steering angle is δ. rear ;K i This is a stability factor.

[0023] Preferably, the vehicle stability control algorithm specifically used in step B further includes:

[0024] Side slip angle compensation method: If the side slip angle β exceeds the threshold (e.g., 3°), the rear wheel steering correction is added: ;

[0025] Feedforward control method: Based on the driver's steering wheel angle δ drive And vehicle speed V x Pre-compensation for rear wheel steering angle: .

[0026] A vehicle stability control system based on rear-wheel steering includes: a sensor signal receiving subsystem, a rear-wheel steering mode controller, and an actuator; wherein,

[0027] The sensor signal receiving subsystem is used to receive input signals from the following sensors: yaw rate sensor, lateral acceleration sensor, steering wheel angle sensor, vehicle speed sensor, and wheel speed sensor. The sensor signal receiving subsystem is connected to the electronic control unit (ECU) via data connection, or to the ECU via an advanced driver assistance system (ADAS). It performs calculations using the sensor data carried by the sensor signals and the vehicle stability control algorithm to obtain the desired yaw rate, yaw rate feedback control amount, sideslip angle compensation method, superimposed rear wheel steering correction amount, and the advance compensation rear wheel steering angle calculated based on the feedforward control method.

[0028] The rear wheel steering mode controller is installed in the integrated brake control (IBC) system and is used to implement the vehicle motion control (VMC) function by selecting the rear wheel steering mode.

[0029] The actuator is used to control the rear wheel steering motor of the vehicle.

[0030] An electronic device, comprising:

[0031] One or more processors;

[0032] Memory, used to store one or more programs;

[0033] When the one or more programs are executed by the one or more processors, the one or more processors implement any of the above-described rear-wheel steering-based vehicle stability control methods.

[0034] A computer-readable medium storing a computer program that, when executed by a processor, implements the steps in any of the aforementioned vehicle stability control methods based on rear-wheel steering.

[0035] The vehicle stability control method and system based on rear-wheel steering provided by this invention can significantly improve the vehicle's dynamic control capability by actively adjusting the rear wheel steering angle. Compared with traditional stability control systems that rely solely on front wheel steering and braking intervention (such as ESP / ESC), it has outstanding advantages such as enhanced dynamic response and handling flexibility, more precise yaw moment control, improved stability under extreme conditions, suppression of oversteer / understeer, potential for multi-dimensional collaborative control, and reduction of the impact of electronic system limitations. Furthermore, by adopting a global collaborative control strategy, the rear wheel steering angle is incorporated as an active control variable into the ESC system for the first time, breaking through the limitations of traditional technologies that rely solely on braking. A multi-objective optimization algorithm is employed, based on model predictive control (MPC), to optimize yaw moment distribution in real time, balancing stability and comfort. An adaptive weighting mechanism is used to dynamically adjust the coordination ratio of rear wheel steering and braking according to vehicle speed and road conditions, improving system robustness. Actively generating yaw moment through rear wheel steering reduces reliance on the braking system, extending brake life. Moreover, on low-traction surfaces, steering intervention is less likely to cause tire slippage than braking, further improving vehicle safety and enabling smoother body posture adjustments, further enhancing ride comfort. Attached Figure Description

[0036] Figure 1 A schematic flowchart of a vehicle stability control method based on rear-wheel steering provided in an embodiment of the present invention;

[0037] Figure 2 A block diagram of a vehicle stability control system based on rear-wheel steering provided in an embodiment of the present invention;

[0038] Figure 3 This is a block diagram of another vehicle stability control system based on rear-wheel steering provided in an embodiment of the present invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solutions of the present invention, exemplary embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0040] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0041] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded. Terms such as “connected” or “linked” are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect.

[0043] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0044] In the technical solution of this invention, the collection, storage, use, processing, transmission, provision, and disclosure of user personal information all comply with relevant laws and regulations and do not violate public order and good morals. The use of user data in this technical solution follows relevant national laws and regulations (e.g., the "Information Security Technology - Personal Information Security Specification"). For example: appropriate measures are taken for personal information access control; restrictions are imposed on the display of personal information; the purpose of using personal information does not exceed the scope of direct or reasonable association; and explicit identity targeting is eliminated when using personal information to avoid precisely locating a specific individual.

[0045] In the related art, (the related art is analyzed, and the technical problem solved by this application is pointed out)

[0046] To address at least one of the technical problems existing in the aforementioned related technologies, the present invention provides a vehicle stability control method and system based on rear-wheel steering.

[0047] Figure 1 This is a schematic flowchart of a vehicle stability control method based on rear-wheel steering, provided as an embodiment of the present invention.

[0048] like Figure 1 As shown, this vehicle stability control method based on rear-wheel steering mainly includes the following steps:

[0049] Step 11: Real-time vehicle status monitoring and instability determination. A vehicle dynamics model is constructed using sensor data, and the deviation Δγ between the actual yaw rate (γ_actual) and the ideal yaw rate (γ_target) is calculated. If Δγ exceeds a threshold or tire lateral force saturation occurs, the vehicle is determined to have entered an instability state. This instability state includes decreased yaw stability and decreased lateral stability.

[0050] In one embodiment of the present invention, the control parameters and control objective of the vehicle state are as follows:

[0051] Regarding yaw stability: The main focus is on suppressing excessive deviations in the vehicle's yaw rate to prevent fishtailing or understeer. The yaw rate deviation is the difference between the actual measured value and the expected value.

[0052] For lateral stability: the main focus is on controlling the vehicle's lateral acceleration and sideslip angle to keep them within safe limits. The sideslip angle refers to the vehicle's center of gravity sideslip angle.

[0053] For path tracking: mainly through rear-wheel steering assist, the vehicle can accurately follow the path desired by the driver.

[0054] Step 12: For different vehicle instability states, adopt corresponding rear-wheel steering-braking coordinated control strategies, mainly including:

[0055] For understeer scenarios: the rear wheels rotate in the same direction as the front wheels (at high speeds) or rotate in opposite directions at a small angle (at low speeds) to increase the yaw moment of the entire vehicle; or / and apply braking force to the inner rear wheel to further suppress the understeer effect.

[0056] For oversteer scenarios, the rear wheels are quickly reversed to counteract the rear-end slippage tendency; or / and the outer front wheels are braked to help restore the vehicle's posture.

[0057] In one embodiment, the rear-wheel steering mode of the vehicle depends primarily on the vehicle speed: when the vehicle is at low speed, the rear wheels are controlled to steer in the opposite direction; when the vehicle is at high speed, the rear wheels are controlled to steer in the same direction.

[0058] The steering wheel angle corresponds to the driver's intention. At low speeds (default speed < 50 km / h), the rear wheels steer in the opposite direction to the front wheels to improve maneuverability and reduce the turning radius; at high speeds (default speed >= 50 km / h), the rear wheels steer in the same direction as the front wheels to enhance stability and suppress yaw.

[0059] Step 122: Steps for controlling weight allocation.

[0060] Specifically, this involves dynamically adjusting the contribution ratio of rear-wheel steering to braking based on the road surface adhesion coefficient and vehicle speed. For example, prioritizing steering intervention on low-traction surfaces reduces the risk of skidding caused by braking.

[0061] In one embodiment of the present invention, the following vehicle stability control algorithm is specifically employed. Wherein:

[0062] (1) The desired yaw rate is calculated using the following formula:

[0063] Where: L is the wheelbase, K is the stability factor, and δ front This refers to the steering angle of the front wheels.

[0064] (2) The yaw rate feedback control quantity is calculated using the following formula:

[0065] ;

[0066] Where: based on the actual yaw rate γ real With γ des To account for the deviation, design a proportional-integral-derivative (PID) controller; the output rear wheel steering angle is δ. rear ;K i This is a stability factor.

[0067] Preferably, it also includes:

[0068] (3) Side slip angle compensation method: If the side slip angle β exceeds the threshold (e.g., 3°), the rear wheel steering correction amount is added: ;

[0069] (4) Feedforward control method: Based on the driver's steering wheel angle δ drive And vehicle speed V x Pre-compensation for rear wheel steering angle: .

[0070] Furthermore, it also includes:

[0071] Step 13: Torque coordination and smooth transition. Reduce the torque of the drive wheels through the powertrain while ensuring a smooth change in the rear wheel steering angle to avoid driving shock.

[0072] Based on the same inventive concept, embodiments of the present invention also provide a vehicle stability control system based on rear-wheel steering.

[0073] Figure 2 This is a block diagram of a vehicle stability control system based on rear-wheel steering, provided as an embodiment of the present invention. Figure 3 This is a block diagram of another vehicle stability control system based on rear-wheel steering provided in an embodiment of the present invention.

[0074] like Figure 2 and Figure 3 As shown, this vehicle stability control system based on rear-wheel steering mainly includes: a sensor signal receiving subsystem, a rear-wheel steering mode controller, and actuators. Among them,

[0075] The sensor signal receiving subsystem is mainly used to receive input signals from the following sensors: yaw rate sensor, lateral acceleration sensor, steering wheel angle sensor, vehicle speed sensor, and wheel speed sensor. The sensor signal receiving subsystem is connected to the electronic control unit (ECU) or to the ECU via an Advanced Driver Assistance System (ADAS). By combining the sensor data carried by the sensor signals with the vehicle stability control algorithm, it calculates the desired yaw rate, the yaw rate feedback control amount, the sideslip angle compensation method, the superimposed rear wheel steering correction amount, and the advance compensation rear wheel steering angle calculated based on the feedforward control method.

[0076] In this embodiment of the invention, the ADAS can calculate the data received by the sensors, the vehicle stability control algorithm, and the electronic control unit (ECU) to obtain the corresponding calculation results, which are used to realize the intelligent driving assistance function of the vehicle.

[0077] The rear wheel steering mode controller is located in the integrated brake control (IBC) system and is used to implement vehicle motion control (VMC) functions by selecting the rear wheel steering mode.

[0078] The actuator is used to control the rear wheel steering motor of the vehicle.

[0079] In embodiments of the present invention, data acquisition is achieved by acquiring signals such as vehicle speed, steering wheel angle, and yaw rate in real time through various sensors; mode switching at different vehicle speeds is achieved by selecting the rear wheel steering mode based on vehicle speed; vehicle state is predicted using a two-degree-of-freedom vehicle dynamics model; control quantity is calculated by generating rear wheel steering angle commands through integrated feedback and forward feedback control; actuator amplitude is limited by constraining the rear wheel steering angle within a certain physical limit (such as ±5°); and dynamic adjustment of vehicle stability is achieved by adaptively adjusting the control gain based on the road adhesion coefficient through a tire force observer.

[0080] Preferably, the present invention also supports and provides corresponding optimization and robustness improvement measures, including: tire nonlinearity compensation: correcting lateral stiffness using the Dugoff tire model or Magic Formula; multi-objective coordinated control: coordinating with Electronic Stability Program (ESP), and superimposing braking intervention when necessary; and employing sliding mode control (SMC) or H-infty control to address model uncertainties, thereby further improving the robustness of the system.

[0081] Based on the same inventive concept, embodiments of the present invention also provide an electronic device. (See reference) Figure 2 The vehicle stability control system shown is based on rear-wheel steering and is integrated into the electronic device.

[0082] The electronic device includes one or more processors, a memory, and one or more I / O interfaces. The memory stores one or more programs that, when executed by the one or more processors, cause the one or more processors to implement any of the rear-wheel steering-based vehicle stability control methods described in the above embodiments. The one or more I / O interfaces are connected between the processors and the memory and configured to enable information exchange between the processors and the memory.

[0083] Among them, the processor is a device with data processing capabilities, including but not limited to the central processing unit (CPU), MCU, etc.; the memory is a device with data storage capabilities, including but not limited to random access memory (RAM, more specifically such as SDRAM, DDR, etc.), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory (FLASH); the I / O interface (read-write interface) is connected between the processor and the memory, and can realize information interaction between the processor and the memory, including but not limited to the data bus (Bus), etc.

[0084] In some embodiments, the processor, memory, and I / O interfaces are interconnected via a bus, and thus connected to other components of the computing device.

[0085] In some embodiments, the one or more processors include a field-programmable gate array (FPGA).

[0086] This invention also provides a computer-readable medium. The computer-readable medium stores a computer program, which, when executed by a processor, implements the steps of any of the rear-wheel steering-based vehicle stability control methods described in the above embodiments. The computer-readable storage medium may be volatile or non-volatile.

[0087] This invention also provides a computer program product, including computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code. When the computer-readable code is run in the processor of an electronic device, the processor in the electronic device executes the above-described vehicle stability control method based on rear-wheel steering.

[0088] Those skilled in the art will understand that all or some of the steps, systems, and apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software can be distributed on a computer-readable storage medium, which may include computer storage media (or non-transitory media) and communication media (or transient media).

[0089] As is known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable program instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), flash memory or other memory technologies, portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, it is known to those skilled in the art that communication media typically contain computer-readable program instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0090] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0091] The computer program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of the invention.

[0092] The computer program product described herein can be implemented specifically through hardware, software, or a combination thereof. In one alternative embodiment, the computer program product is specifically embodied in a computer storage medium; in another alternative embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0093] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0094] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0095] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0096] The method and system of this invention were tested and their implementation effects were verified using the following simulation tools and experimental environment. The simulation environment was: CarSim + MATLAB / Simulink co-simulation was used to verify that under conditions such as emergency lane change and double lane change, the vehicle yaw rate tracking error was < 10%, the absolute value of the sideslip angle was < 5°, and the path tracking deviation was < 0.3 m.

[0097] Compared to traditional vehicle stability control systems that rely solely on front-wheel steering and braking intervention, the method and system of this invention offer the following significant technical advantages:

[0098] (1) Enhance dynamic response and handling agility. Low-speed agility: At low speeds, the rear wheels rotate in the opposite direction to the front wheels (e.g., a maximum of 10°), reducing the turning radius (e.g., the turning radius of the Mengshi 917 is reduced by about 1 meter), improving handling in tight spaces. High-speed stability: At high speeds (>60km / h), the rear wheels rotate in the same direction as the front wheels (e.g., 2°), virtually extending the wheelbase (e.g., for vehicles longer than 5.1 meters, rear wheel steering can effectively increase the wheelbase by 0.3 meters), suppressing yaw vibration and improving stability during lane changes or cornering.

[0099] (2) More precise yaw moment control. Direct intervention in vehicle attitude: Traditional ESP relies on braking on one side of the wheel to generate yaw moment, which may lead to power interruption and jerking; rear-wheel steering directly corrects the vehicle's yaw angle by adjusting the lateral force of the rear wheels (e.g., reducing steering correction by about 15% during emergency obstacle avoidance). Reduced reliance on braking: On low-traction surfaces (such as ice and snow), adjusting the vehicle's trajectory through rear-wheel steering can reduce the risk of tire lock-up caused by excessive braking system intervention and maintain higher vehicle speeds.

[0100] (3) Improve stability under extreme conditions. Suppress oversteer / understeer: When the vehicle oversteers, the rear wheel steering can actively compensate in the opposite direction (e.g., the rear wheels turn outwards), quickly restoring the vehicle's balance (reducing the yaw rate error of the vehicle in extreme cornering by 20%). For understeer, the rear wheels turning in the same direction can increase the lateral force and assist the front wheels in completing the steering. Drift control: High-performance models (such as coupes) allow the rear wheel steering to work in conjunction with ESC in track mode, using precise rear wheel angle adjustment to assist in maintaining controllable drift.

[0101] (4) Potential for multi-dimensional collaborative control. Deep integration with ESP / ESC: Rear-wheel steering can be linked with traditional stability control systems to form a four-dimensional control architecture of "front-wheel steering + rear-wheel steering + braking force distribution + power control". For example, during emergency braking, slight rear-wheel steering can optimize load distribution and shorten braking distance (experimental data shows a reduction of about 5%). During high-speed lane changes, rear-wheel steering and ESC work together to suppress body roll and improve passenger comfort.

[0102] (5) Reduce the impact of electronic system limitations. Reduce sensor error sensitivity: The mechanical adjustment of rear wheel steering can partially compensate for control lag caused by sensor delay or error (e.g., when the yaw rate sensor fails, rear wheel steering can still provide basic stability). Optimize energy efficiency: Compared to frequent braking intervention (which leads to kinetic energy being converted into heat loss), the mechanical control of rear wheel steering is more energy-efficient, especially in electric vehicles, which can extend the driving range.

[0103] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A vehicle stability control method based on rear wheel steering, characterized by, The method comprises the following steps: Real-time monitoring and instability determination of vehicle state; constructing a vehicle dynamics model through sensor data, calculating the deviation Δγ of the actual yaw rate γ_actual and the ideal yaw rate γ_target; if Δγ exceeds the threshold or the tire lateral force is saturated, it is determined that the vehicle enters an unstable state; For different vehicle instability states, the step of adopting a corresponding rear wheel steering-braking collaborative control mode.

2. The method of claim 1, wherein, After the step of adopting a corresponding rear wheel steering-braking collaborative control mode for different vehicle instability states, further comprising: Torque coordination and smooth transition steps; reduce the driving wheel torque through the power system, while ensuring that the rear wheel steering angle change rate is gentle, avoiding driving impact.

3. The method of claim 1, wherein, The vehicle instability state includes lateral stability deterioration and lateral stability deterioration.

4. The method of claim 1, wherein, The control step of adopting rear wheel steering-braking collaboration comprises: For understeering scenarios, control the rear wheels to rotate in the same direction as the front wheels or small-angle reverse rotation to increase the overall vehicle yaw moment; or apply a braking force to the inner rear wheel to suppress the push effect; For oversteering scenarios, control the rear wheels to quickly reverse deflection to offset the tail side slip trend; or brake the outer front wheel to assist in restoring the vehicle body posture.

5. The method of claim 4, wherein, The control step of adopting rear wheel steering-braking collaboration further comprises: A step of controlling weight distribution, dynamically adjusting the contribution ratio of rear wheel steering and braking based on road adhesion coefficient and vehicle speed.

6. The method of claim 1, wherein, In the step of adopting a corresponding rear wheel steering-braking collaborative control mode for different vehicle instability states, the specific vehicle stability control algorithm adopted comprises: (1) Calculate the expected yaw rate using the following formula: ; where: L is wheel base, K is stability factor, δ front is front wheel steering angle; (2) Calculate the yaw rate feedback control amount using the following formula: ； Wherein: according to the actual yaw rate γ real The deviation of γ des , design proportional-integral-derivative PID controller; the output rear wheel rotation angle is δ rear ; K i is a stability factor.

7. The method of claim 6, wherein, In the step of adopting a corresponding rear wheel steering-braking collaborative control mode for different vehicle instability states, the specific vehicle stability control algorithm further comprises: Side slip angle compensation method: if the side slip angle β exceeds a threshold value (e.g. 3°), the rear wheel steering correction amount is superimposed: ; Feedforward control mode: based on the driver's steering wheel angle δ drive and vehicle speed V x , to compensate for the rear wheel angle in advance: .

8. A rear wheel steering based vehicle stability control system characterized by, It comprises: A sensor signal receiving subsystem, a rear wheel steering mode controller and an actuator; wherein The sensor signal receiving subsystem is used to receive input signals from the following sensors: yaw rate sensor, lateral acceleration sensor, steering wheel angle sensor, vehicle speed sensor, wheel speed sensor; the sensor signal receiving subsystem is data connected with the electronic control unit ECU, or is data connected with the ECU through the advanced driving assistance system ADAS, and the sensor data carried by the sensor signal is combined with the vehicle stability control algorithm to obtain the expected yaw rate, the yaw rate feedback control amount, the side slip angle compensation mode and the superimposed rear wheel steering correction amount, and the front compensation rear wheel angle amount calculated according to the feedforward control mode; The rear wheel steering mode controller is arranged in the integrated brake control IBC system and is used to realize the vehicle motion control VMC function by selecting the rear wheel steering mode; The actuator is used to control the vehicle rear wheel steering motor.

9. An electronic device, comprising: It comprises: One or more processors; Memory for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement a method as claimed in any of claims 1 to 7.

10. A computer readable medium having stored thereon a computer program, characterized in that The computer program, which when executed by a processor, implements the steps of a method as claimed in any of claims 1 to 7.

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