Rear wheel steering control method and system based on zero side slip angle

Abstract

The invention relates to a rear wheel steering control method and system based on a zero side slip angle, and belongs to the technical field of vehicle power control. The rear wheel steering control method based on the zero side slip angle comprises the following steps that a vehicle linear two-degree-of-freedom kinetic model is constructed, and a requested rear wheel steering angle is proportional to a steering wheel steering angle; obtaining a calculation model of the requested rear wheel steering angle of the zero side slip angle; calculating a requested rear wheel rack displacement based on the computational model; rear wheel steering is controlled based on the requested rear wheel rack displacement. According to the method, the direction stability, the track keeping capacity and the active safety of the vehicle under various working conditions can be remarkably improved by directly keeping the side slip angle of the vehicle at zero (or minimum) as a core control target and accurately and coordinately controlling the rear wheel turning angle.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of vehicle power control, and in particular relates to a rear wheel steering control method and system based on a zero center of mass sideslip angle. Background Art

[0002] Vehicle handling stability is a core indicator of active safety, especially crucial in extreme driving conditions such as high-speed driving or emergency obstacle avoidance. Traditional steering systems rely solely on front-wheel steering, often struggling to balance low-speed agility with high-speed stability.

[0003] Rear-wheel steering technology, an effective means of improving vehicle handling, has been widely adopted in high-end passenger cars and some commercial vehicles in recent years. By actively controlling the steering angle of the rear wheels under specific operating conditions, it can rotate the rear wheels in the opposite direction of the front wheels at low speeds, effectively reducing the turning radius and improving vehicle maneuverability. At high speeds, the rear wheels can rotate in the same direction as the front wheels, enhancing yaw damping and track stability, and improving safety and ride comfort when changing lanes or cornering at high speeds.

[0004] Currently, mainstream rear-wheel steering control strategies are primarily based on vehicle state variables such as yaw rate and lateral acceleration, employing feedforward and feedback control. However, this yaw rate-focused control strategy suffers from significant issues and limitations, including insufficient control of the center of mass slip angle. While existing control strategies indirectly influence the center of mass slip angle, they typically fail to directly and precisely constrain or zero the slip angle as a core control objective. Under extreme operating conditions such as high speeds, high lateral accelerations, or low-adhesion surfaces, the vehicle may still experience significant or even dangerous slip angles, resulting in fuzzy stability boundaries. Simply tracking the yaw rate cannot fully guarantee that the vehicle remains in the stable phase plane. A vehicle may meet the yaw rate target while approaching or exceeding the stability limit.

[0005] In summary, existing rear-wheel steering control technologies primarily focus on yaw rate tracking and stability enhancement, lacking an active rear-wheel steering control method that directly targets "zero center of mass sideslip angle." This lack prevents the vehicle's inherent lateral stability potential from being fully exploited in extreme driving conditions, posing a safety hazard.

[0006] Therefore, it is necessary to provide a new rear wheel steering control method and system based on zero center of mass sideslip angle to solve the above technical problems. Summary of the Invention

[0007] The purpose of the present disclosure is to provide a rear wheel steering control method and system based on zero center of mass sideslip angle in order to solve the above problems.

[0008] The present disclosure achieves the above objectives through the following technical solutions: A rear wheel steering control method based on zero center of mass sideslip angle comprises the following steps: Construct a linear two-degree-of-freedom dynamic model for the vehicle, proportionalize the requested rear wheel steering angle to the steering wheel angle, and obtain a calculation model for the requested rear wheel steering angle at zero center of mass sideslip angle. calculating a requested rear wheel rack displacement based on the calculation model; Rear wheel steering is controlled based on the requested rear wheel rack displacement.

[0009] As a further optimization solution of the present disclosure, a linear two-degree-of-freedom dynamic model of the vehicle is constructed, and the requested rear wheel steering angle is proportional to the steering wheel angle. A calculation model for the requested rear wheel steering angle with zero center of mass sideslip angle is obtained, including: Construct a linear two-degree-of-freedom dynamic model of the vehicle; Based on the vehicle's linear two-degree-of-freedom dynamics model, a steady-state equilibrium equation for rear-wheel steering is constructed; Within the linear range, the cornering stiffness of the front and rear wheels is preset, and based on the steady-state equilibrium equation of the rear wheel steering and the cornering stiffness of the front and rear wheels, the relationship between the lateral force of the front and rear wheels and their sideslip angles is obtained; Based on the relationship between the front and rear wheel lateral forces and their sideslip angles, a two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle is obtained; Based on the two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle, the rear wheel angle is proportional to the front wheel angle, and the front and rear wheel angles are represented by the steering wheel angle, respectively. The response equations of the vehicle's sideslip angle and yaw rate to the steering wheel angle are obtained when the rear wheel angle is proportional to the front wheel angle; A proportionality constant of the rear wheel steering angle relative to the front wheel steering angle is set, and a calculation model of the requested rear wheel steering angle at zero center of mass sideslip angle is expressed based on the response equation and the proportionality constant.

[0010] As a further optimization solution of the present disclosure, calculating the requested rear wheel rack displacement based on the calculation model includes: Inputting basic vehicle parameters into the calculation model to calculate the requested rear wheel angle; Converting the requested rear wheel steering angle into a requested rear wheel rack displacement based on the rear axle steering trapezoidal geometry; limiting the rate of change and range of the requested rear wheel rack displacement according to the vehicle speed; The restricted rear wheel rack displacement is filtered to obtain the effective rear wheel rack displacement.

[0011] As a further optimization solution of the present disclosure, the basic vehicle parameters include the distance from the center of mass to the front and rear axles, curb weight, front and rear axle lateral stiffness, steering wheel angle and vehicle speed.

[0012] A rear wheel steering control system based on zero center of mass sideslip angle, comprising: A model building module is used to build a linear two-degree-of-freedom dynamic model of the vehicle, proportionally calculate the requested rear wheel angle to the steering wheel angle, and obtain a calculation model of the requested rear wheel angle at zero center of mass sideslip angle; a rear wheel rack displacement calculation module, configured to calculate a requested rear wheel rack displacement based on the calculation model; A rear wheel steering control module is configured to control rear wheel steering based on the requested rear wheel rack displacement.

[0013] As a further optimization solution of the present disclosure, the model building module constructs a linear two-degree-of-freedom dynamic model of the vehicle, proportionalizes the requested rear wheel steering angle to the steering wheel angle, and obtains a calculation model of the requested rear wheel steering angle with zero center of mass sideslip angle, including: Construct a linear two-degree-of-freedom dynamic model of the vehicle; Based on the vehicle's linear two-degree-of-freedom dynamics model, a steady-state equilibrium equation for rear-wheel steering is constructed; Within the linear range, the cornering stiffness of the front and rear wheels is preset, and based on the steady-state equilibrium equation of the rear wheel steering and the cornering stiffness of the front and rear wheels, the relationship between the lateral force of the front and rear wheels and their sideslip angles is obtained; Based on the relationship between the front and rear wheel lateral forces and their sideslip angles, a two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle is obtained; Based on the two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle, the rear wheel angle is proportional to the front wheel angle, and the front and rear wheel angles are represented by the steering wheel angle, respectively. The response equations of the vehicle's sideslip angle and yaw rate to the steering wheel angle are obtained when the rear wheel angle is proportional to the front wheel angle; A proportionality constant of the rear wheel steering angle relative to the front wheel steering angle is set, and a calculation model of the requested rear wheel steering angle at zero center of mass sideslip angle is expressed based on the response equation and the proportionality constant.

[0014] As a further optimization solution of the present disclosure, the rear wheel rack displacement calculation module calculates the requested rear wheel rack displacement based on the calculation model, including: Inputting basic vehicle parameters into the calculation model to calculate the requested rear wheel angle; Converting the requested rear wheel steering angle into a requested rear wheel rack displacement based on the rear axle steering trapezoidal geometry; limiting the rate of change and range of the requested rear wheel rack displacement according to the vehicle speed; The restricted rear wheel rack displacement is filtered to obtain the effective rear wheel rack displacement.

[0015] As a further optimization solution of the present disclosure, the basic vehicle parameters include the distance from the center of mass to the front and rear axles, curb weight, front and rear axle lateral stiffness, steering wheel angle and vehicle speed.

[0016] A vehicle equipped with a rear-wheel steering control system based on a zero-center-of-mass sideslip angle comprises a rear-wheel steering system, a vehicle speed sensor, and a steering wheel angle sensor; The rear-wheel steering system includes a linear displacement sensor, a rear-wheel steering controller, and a rear-wheel steering actuator motor; The linear displacement sensor is used to detect the actual position of the rear wheel steering rack; The rear wheel steering controller is used to collect sensor signals, make judgments, and ultimately send a current request to the execution motor; The rear wheel steering execution motor is used to execute the current request sent by the rear wheel steering controller; The vehicle speed sensors are installed on the four wheels, and the braking system calculates the four wheel speeds based on the pulse signals and calculates the vehicle speed; The steering wheel angle sensor is used to collect the actual angle at which the driver turns the steering wheel.

[0017] An electronic device, comprising a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; Memory for storing computer programs; The processor is used to execute the program stored in the memory to implement the rear wheel steering control method based on zero center of mass sideslip angle.

[0018] The beneficial effects of the present disclosure are: The present invention can directly maintain the vehicle's center of mass sideslip angle at zero (or extremely small) as the core control target, and significantly improve the vehicle's directional stability, trajectory keeping ability and active safety under various working conditions by precisely and coordinately controlling the rear wheel angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of a method in an embodiment of the present disclosure; Figure 2 is a schematic diagram of a two-degree-of-freedom dynamic model of rear-wheel steering in an embodiment of the present disclosure; Figure 3 is a system framework diagram in an embodiment of the present disclosure; Figure 4 is a schematic diagram of a vehicle equipped with a rear-wheel steering control system based on a zero center of mass sideslip angle in an embodiment of the present disclosure; Figure 5 is a graph showing a serpentine-type lateral acceleration-steering wheel angle response characteristic curve measured by a rear-wheel steering control method based on a zero center of mass sideslip angle in an embodiment of the present disclosure; Figure 6is a graph showing a serpentine working condition yaw rate-steering wheel angle response characteristic curve measured by a rear wheel steering control method based on a zero center of mass sideslip angle in an embodiment of the present disclosure; Figure 7 is a graph showing a characteristic curve of a center-of-mass slip angle response under a double lane-changing condition measured by a rear-wheel steering control method based on a zero center-of-mass slip angle in an embodiment of the present disclosure; Figure 8 It is a framework diagram of an electronic device in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] The present application is described in further detail below in conjunction with the accompanying drawings. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0021] like Figure 1 As shown, a rear wheel steering control method based on zero center of mass sideslip angle includes the following steps: S1. Construct a linear two-degree-of-freedom dynamic model for the vehicle, proportionalize the requested rear wheel steering angle to the steering wheel angle, and obtain a calculation model for the requested rear wheel steering angle at zero center of mass sideslip angle, specifically including: First, establish the vehicle linear two-degree-of-freedom dynamic model, such as Figure 2 As shown, the steady-state equilibrium equation of the rear wheel steering is constructed: ; ; In the above formula, F y1 、F y2 Represent the lateral forces on the front and rear wheels respectively, a, b Represent the distance from the center of mass to the front and rear axes, V represents the center of mass velocity, m Indicates the vehicle mass, β represents the sideslip angle of the center of mass, ω represents the vehicle's yaw rate, I represents the yaw moment of inertia.

[0022] In the linear range, the cornering stiffness of the front and rear wheels are K f 、K r , then the relationship between the front and rear wheel lateral forces and their sideslip angles can be expressed as: ; ; Where, af is the front wheel slip angle, a r is the rear wheel slip angle, δ f is the front wheel turning angle, δ r is the rear wheel turning angle.

[0023] From this, the two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle can be obtained as follows: ; ; The control method of rear wheel angle being proportional to front wheel angle is adopted. In this case, the front and rear wheel angles can be expressed as steering wheel angles: ; ; Where, δ Indicates the steering wheel angle, n Indicates the transmission ratio from steering wheel angle to front wheel angle. k Indicates the proportional coefficient of the rear wheel angle to the front wheel angle.

[0024] At this point, the response of the vehicle's sideslip angle and yaw rate to the steering wheel angle can be obtained when the rear wheel angle is proportional to the front wheel angle: ; Where, is the expression for the sideslip angle at the center of mass, is the steering wheel angle expression, is the moment of inertia.

[0025] Set the proportional constant of the rear wheel angle relative to the front wheel angle to be k , so that the numerator in the above formula is zero k It can be expressed as: ; At this time, the vehicle's center of mass sideslip angle is always zero during steady-state steering, that is, the vehicle's driving direction is consistent with the vehicle's heading direction. The requested rear wheel steering angle can be expressed as: .

[0026] S2. Calculating the requested rear wheel rack displacement based on the calculation model, specifically including: Input signals such as the distance from the center of mass to the front and rear axles, the curb mass, the front and rear axle cornering stiffness, the steering wheel angle, and the vehicle speed are input into a calculation model for the requested rear wheel steering angle at zero center of mass sideslip angle to calculate the requested rear wheel steering angle; Convert the calculated requested rear wheel steering angle into requested rear wheel rack displacement according to the rear axle steering trapezoidal geometry; The rate of change and range of the requested rear wheel rack displacement are limited according to the vehicle speed to prevent the signal from exceeding the reasonable range; Filter the restricted rear wheel rack displacement to prevent signal jumps; Output the final effective requested rear wheel rack displacement.

[0027] S3, controlling rear wheel steering based on the requested rear wheel rack displacement, specifically comprising: The requested rear wheel rack displacement is transmitted to the rear wheel steering controller, which controls the rear wheel steering execution motor to rotate, push the rear wheel steering gear, and thus drive the rear wheels to rotate.

[0028] like Figure 3 As shown, an embodiment of the present disclosure provides a rear wheel steering control system based on zero center of mass sideslip angle, comprising: A model building module is used to build a linear two-degree-of-freedom dynamic model of the vehicle, proportionally calculate the requested rear wheel angle to the steering wheel angle, and obtain a calculation model of the requested rear wheel angle at zero center of mass sideslip angle; a rear wheel rack displacement calculation module, configured to calculate a requested rear wheel rack displacement based on the calculation model; A rear wheel steering control module is configured to control rear wheel steering based on the requested rear wheel rack displacement.

[0029] The implementation process of the functions and effects of each module in the above system is specifically described in the implementation process of the corresponding steps in the above method, which will not be repeated here.

[0030] For the system embodiment, since it basically corresponds to the method embodiment, the relevant parts can be referred to the partial description of the method embodiment. The system embodiment described above is only schematic, wherein the modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the disclosed solution. Those of ordinary skill in the art can understand and implement it without paying any creative work.

[0031] like Figure 4 As shown, the present disclosure also proposes a vehicle with a rear-wheel steering control system based on a zero center of mass sideslip angle, the architectural features of which include: Rear wheel steering system 3, vehicle speed sensor 2, steering wheel angle sensor 1.

[0032] The rear wheel steering system 3 includes a linear displacement sensor, a rear wheel steering controller, and a rear wheel steering execution motor; The linear displacement sensor is used to detect the actual position of the rear wheel steering rack; The rear wheel steering controller is used to collect sensor signals, make judgments, and ultimately send a current request to the execution motor; The rear wheel steering execution motor is used to execute the current request sent by the rear wheel steering controller; The vehicle speed sensor 2 is installed on the four wheels, and the braking system calculates the four wheel speeds based on the pulse signal and calculates the vehicle speed; The steering wheel angle sensor 1 is used to collect the actual angle of the steering wheel turned by the driver.

[0033] A serpentine test was conducted on a vehicle equipped with the rear-wheel steering system based on zero center of mass slip angle. The test method was as follows: the vehicle speed was maintained at a constant 120km / h, and the steering wheel was rotated in the form of a sinusoidal input. The positive period of the steering wheel input angle was 4s and the amplitude was 60°. The steering wheel angle signal, lateral acceleration signal, and yaw rate signal were collected during the test. The collected signals were filtered and compared with the conventional feedforward rear-wheel steering control strategy and the closed rear-wheel steering strategy. The results are as follows: Figure 5 、 Figure 6 As shown: The response of the vehicle's lateral acceleration to the steering wheel angle and the response of the yaw rate to the steering wheel angle using the rear-wheel steering control strategy with zero center of mass sideslip angle improves high-speed stability by approximately 35% compared to the strategy with rear-wheel steering disabled, and by approximately 15% compared to the feedforward control strategy; Figure 5 In the figure, the ordinate LateralAcceleration is the lateral acceleration, the abscissa SteeringWheelAngle is the steering wheel angle, On Zero-Beta RWS is the curve of the rear-wheel steering strategy based on the zero center of mass sideslip angle, Standand RWS is the curve of the feedforward control rear-wheel steering strategy, and WithoutRWS is the curve of turning off the rear-wheel steering; Figure 6 In the equation, the vertical coordinate Yawrate is the yaw angular velocity; A double lane change test was conducted on a vehicle equipped with the rear-wheel steering system based on zero center of mass slip angle. The test method was as follows: maintaining an initial speed of 120 km / h, the vehicle was controlled to change lanes to the left as quickly as possible, and after completing the lane change, the vehicle was quickly controlled to change lanes to the right again until the vehicle body stabilized. The center of mass slip angle signal during the test was collected and filtered. The collected signal was then compared with the conventional feedforward rear-wheel steering control strategy and the closed rear-wheel steering strategy. The results are as follows: Figure 7 As shown: The vehicle's center of mass slip angle using the rear-wheel steering control strategy with zero center of mass slip angle is reduced by about 33% compared to the strategy with closed rear-wheel steering, and by about 8% compared to the feedforward control strategy. Figure 7 The vertical coordinate Beta is the sideslip angle of the center of mass, and the horizontal coordinate Time is time (s).

[0034] Experiments have shown that using a zero center of mass slip angle control strategy can significantly increase lateral stability at high speeds, while significantly reducing the center of mass slip angle, essentially keeping the center of mass slip angle close to zero.

[0035] See also Figure 8 The electronic device provided by an embodiment of the present disclosure includes a processor 1110, a communication interface 1120, a memory 1130 and a communication bus 1140, wherein the processor 1110, the communication interface 1120, and the memory 1130 communicate with each other through the communication bus 1140; Memory 1130, for storing computer programs; The processor 1110 is configured to implement the aforementioned rear wheel steering control method based on zero center of mass sideslip angle when executing the program stored in the memory 1130 . The communication bus 1140 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The communication bus 1140 can be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, the figure shows only one thick line, but this does not mean that there is only one bus or only one type of bus.

[0036] The communication interface 1120 is used for communication between the electronic device and other devices.

[0037] The memory 1130 may include a random access memory (RAM) or a non-volatile memory, such as at least one disk storage. Alternatively, the memory 1130 may be at least one storage device located away from the processor 1110.

[0038] The above-described embodiments merely represent several implementation methods of the present disclosure. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present disclosure. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the scope of the present disclosure, all of which fall within the scope of protection of the present disclosure.

Claims

1. A rear wheel steering control method based on zero center of mass sideslip angle, characterized in that: The following steps are involved: Construct a linear two-degree-of-freedom dynamic model for the vehicle, proportionalize the requested rear wheel steering angle to the steering wheel angle, and obtain a calculation model for the requested rear wheel steering angle at zero center of mass sideslip angle. calculating a requested rear wheel rack displacement based on the calculation model; Rear wheel steering is controlled based on the requested rear wheel rack displacement.

2. The rear wheel steering control method based on zero center of mass sideslip angle according to claim 1, characterized in that: Construct a linear two-degree-of-freedom dynamic model for the vehicle, and make the requested rear wheel steering angle proportional to the steering wheel angle. This calculation model for the requested rear wheel steering angle at zero center of mass slip angle is obtained, including: Construct a linear two-degree-of-freedom dynamic model of the vehicle; Based on the vehicle's linear two-degree-of-freedom dynamics model, a steady-state equilibrium equation for rear-wheel steering is constructed; Within the linear range, the cornering stiffness of the front and rear wheels is preset, and based on the steady-state equilibrium equation of the rear wheel steering and the cornering stiffness of the front and rear wheels, the relationship between the lateral force of the front and rear wheels and their sideslip angles is obtained; Based on the relationship between the front and rear wheel lateral forces and their sideslip angles, a two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle is obtained; Based on the two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle, the rear wheel angle is proportional to the front wheel angle, and the front and rear wheel angles are represented by the steering wheel angle, respectively. The response equations of the vehicle's sideslip angle and yaw rate to the steering wheel angle are obtained when the rear wheel angle is proportional to the front wheel angle; A proportionality constant of the rear wheel steering angle relative to the front wheel steering angle is set, and a calculation model of the requested rear wheel steering angle at zero center of mass sideslip angle is expressed based on the response equation and the proportionality constant.

3. The rear wheel steering control method based on zero center of mass sideslip angle according to claim 1, characterized in that: Calculating the requested rear wheel rack displacement based on the calculation model includes: Inputting basic vehicle parameters into the calculation model to calculate the requested rear wheel angle; Converting the requested rear wheel steering angle into a requested rear wheel rack displacement based on the rear axle steering trapezoidal geometry; limiting the rate of change and range of the requested rear wheel rack displacement according to the vehicle speed; The restricted rear wheel rack displacement is filtered to obtain the effective rear wheel rack displacement.

4. The rear wheel steering control method based on zero center of mass sideslip angle according to claim 3, characterized in that: The basic vehicle parameters include the distance from the center of mass to the front and rear axles, curb weight, front and rear axle lateral stiffness, steering wheel angle and vehicle speed.

5. A rear wheel steering control system based on zero center of mass sideslip angle, characterized in that: include: A model building module is used to build a linear two-degree-of-freedom dynamic model of the vehicle, proportionally calculate the requested rear wheel angle to the steering wheel angle, and obtain a calculation model of the requested rear wheel angle at zero center of mass sideslip angle; a rear wheel rack displacement calculation module, configured to calculate a requested rear wheel rack displacement based on the calculation model; A rear wheel steering control module is configured to control rear wheel steering based on the requested rear wheel rack displacement.

6. The rear wheel steering control system based on zero center of mass sideslip angle according to claim 5, characterized in that: The model building module builds a linear two-degree-of-freedom dynamic model of the vehicle, calculates the requested rear wheel turning angle proportional to the steering wheel angle, and obtains a calculation model of the requested rear wheel turning angle with zero center of mass sideslip angle, including: Construct a linear two-degree-of-freedom dynamic model of the vehicle; Based on the vehicle's linear two-degree-of-freedom dynamics model, a steady-state equilibrium equation for rear-wheel steering is constructed; Within the linear range, the cornering stiffness of the front and rear wheels is preset, and based on the steady-state equilibrium equation of the rear wheel steering and the cornering stiffness of the front and rear wheels, the relationship between the lateral force of the front and rear wheels and their sideslip angles is obtained; Based on the relationship between the front and rear wheel lateral forces and their sideslip angles, a two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle is obtained; Based on the two-degree-of-freedom dynamic equation of the rear-wheel steering vehicle, the rear wheel angle is proportional to the front wheel angle, and the front and rear wheel angles are represented by the steering wheel angle, respectively. The response equations of the vehicle's sideslip angle and yaw rate to the steering wheel angle are obtained when the rear wheel angle is proportional to the front wheel angle; A proportionality constant of the rear wheel steering angle relative to the front wheel steering angle is set, and a calculation model of the requested rear wheel steering angle at zero center of mass sideslip angle is expressed based on the response equation and the proportionality constant.

7. The rear wheel steering control system based on zero center of mass sideslip angle according to claim 5, characterized in that: The rear wheel rack displacement calculation module calculates the requested rear wheel rack displacement based on the calculation model, including: Inputting basic vehicle parameters into the calculation model to calculate the requested rear wheel angle; Converting the requested rear wheel steering angle into a requested rear wheel rack displacement based on the rear axle steering trapezoidal geometry; limiting the rate of change and range of the requested rear wheel rack displacement according to the vehicle speed; The restricted rear wheel rack displacement is filtered to obtain the effective rear wheel rack displacement.

8. The rear wheel steering control system based on zero center of mass sideslip angle according to claim 7, characterized in that: The basic vehicle parameters include the distance from the center of mass to the front and rear axles, curb weight, front and rear axle lateral stiffness, steering wheel angle and vehicle speed.

9. A vehicle equipped with a rear wheel steering control system based on zero center of mass sideslip angle according to any one of claims 5 to 8, characterized in that: Includes rear-wheel steering system, vehicle speed sensor and steering wheel angle sensor; The rear-wheel steering system includes a linear displacement sensor, a rear-wheel steering controller, and a rear-wheel steering actuator motor; The linear displacement sensor is used to detect the actual position of the rear wheel steering rack; The rear wheel steering controller is used to collect sensor signals, make judgments, and ultimately send a current request to the execution motor; The rear wheel steering execution motor is used to execute the current request sent by the rear wheel steering controller; The vehicle speed sensors are installed on the four wheels, and the braking system calculates the four wheel speeds based on the pulse signals and calculates the vehicle speed; The steering wheel angle sensor is used to collect the actual angle at which the driver turns the steering wheel.

10. An electronic device, characterized in that: The processor, the communication interface, the memory and the communication bus are connected to each other via the communication bus. Memory for storing computer programs; A processor is used to execute a program stored in a memory to implement the rear wheel steering control method based on zero center of mass sideslip angle according to any one of claims 1 to 4.

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