Rear wheel steering system and multi-mode identification and switching control method, system and medium

Abstract

The application discloses a kind of invention and is related to the technical field of intelligent chassis, specifically, it is rear wheel steering system and multi-mode identification and switching control method, system, medium, motor is carried out closed loop feedback control according to the deviation of rear wheel rotation angle;Control system is according to the mode identification of driving condition that vehicle dynamics model and chassis motion state signal carry out, i.e. it can identify the best working mode of rear wheel steering system currently;Control system carries out adaptive switching control according to the working mode identified, different control strategy is used under different mode, steering ware is under the action of motor control Real-time tracking required rear wheel rotation angle request, make rear wheel follow-up steering system always work in best state.This rear wheel follow-up steering control method utilizes the accurate identification of driving condition and the adaptive switching of multi-mode control, and the closed loop feedback control of multiple parameters, very good solution low speed maneuverability and high speed safety difficult to take into account the problem, and in various different road, different tire pressure, different speed can achieve ideal control effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent chassis, in particular to a rear wheel steering system, a multi-mode identification and switching control method, a system and a medium. BACKGROUND

[0002] Rear wheel steering technology is a control method that improves the steering stability, safety and maneuvering flexibility of a vehicle by actively controlling the rear wheel steering angle. By changing the rear wheel angle, the lateral sideslip and yaw motion of the vehicle are controlled to improve the transient response when the vehicle is turning. Compared with front wheel steering, at low speed, the use of inverse phase steering of front and rear wheels can greatly reduce the turning radius of the vehicle and improve the maneuvering flexibility of the vehicle. At high speed, the four-wheel steering vehicle uses the same phase steering of front and rear wheels to reduce the yaw angular velocity and lateral acceleration of the vehicle and the vehicle's mass center side slip angle, improving the vehicle's tracking ability, so that the vehicle can quickly change lanes in an emergency without losing vehicle stability.

[0003] In the prior art, the rear wheel angle is generally controlled by combining the vehicle speed and the proportional feedforward, but the conventional method in the prior art has poor flexibility and does not consider different working conditions of medium and high speed and tire adhesion, so the rear steering control is not accurate enough. SUMMARY

[0004] The purpose of the present application is to provide a rear wheel steering system, a multi-mode identification and switching control method, a system and a medium to solve the above problems in the prior art.

[0005] The embodiments of the present application are implemented by the following technical solutions:

[0006] In a first aspect, the present application provides a multi-mode identification and switching control method based on a rear wheel steering system, comprising:

[0007] Obtaining system calculation parameters, obtaining a double-critical vehicle speed for working condition identification through the calculation parameters, and determining whether the current working condition is a low-speed working condition or a medium and high-speed working condition,

[0008] If the current working condition is determined to be a low-speed working condition, the expected rear wheel steering angle is obtained according to the front wheel steering angle proportional feedforward, the yaw angular velocity proportional feedback and the tire pressure;

[0009] If the current working condition is determined to be a medium and high-speed working condition, it is determined whether the vehicle is in a medium and high-speed high adhesion working condition or a medium and high-speed low adhesion working condition;

[0010] If the current working condition is a medium and high-speed high adhesion working condition, the expected rear wheel steering angle is obtained according to the front wheel steering angle proportional feedforward;

[0011] If the current working condition is the medium-high speed and low adhesion condition, then the expected rear wheel steering angle is obtained according to the proportional feedback of the centroid side slip angle deviation PI feedback and the yaw rate deviation;

[0012] The actual rear wheel steering angle is obtained, and the motor position, speed and current are controlled by three closed-loop feedback according to the deviation between the actual rear wheel steering angle and the expected rear wheel steering angle, and the rear wheel steering actuator tracks the expected rear wheel steering angle request in real time under the action of motor control.

[0013] In an embodiment of the present application, the double critical vehicle speed includes:

[0014]

[0015] In the formula, m is the mass of the vehicle, a and b are the distances from the vehicle centroid to the front and rear axles respectively, L=a+b is the wheelbase of the front and rear axles, V is the longitudinal vehicle speed, k f ,k r are the cornering stiffness of the front and rear tires respectively, V1 and V2 are the critical vehicle speeds.

[0016] In an embodiment of the present application, the judgment of whether the vehicle is in the medium-high speed and high adhesion condition or the medium-high speed and low adhesion condition includes:

[0017] When V x ≤min(V1,V2), it is a low speed condition; when V x ≥max(V1,V2), it is a medium-high speed condition, wherein V x is the longitudinal vehicle speed.

[0018] In an embodiment of the present application, the expected rear wheel steering angle obtained according to the proportional front wheel steering angle feedforward, the proportional yaw rate feedback and the tire pressure includes:

[0019] δ r =K p (K z1 δ f +K z2 ω r )

[0020] In the formula, δ r is the rear wheel steering angle, K p is the correction coefficient related to the tire pressure, K z1 and K z2 are feedback control gain coefficients, δ f is the front wheel steering angle, and ω r is the yaw rate.

[0021] In an embodiment of the present application, the selection of the correction coefficient is also included, which includes:

[0022] Obtaining the tire pressure of the rear wheel of the vehicle, and setting a standard value and a threshold range, judging whether the tire pressure of the rear wheel of the vehicle is normal according to the standard value:

[0023] If the tire pressure is normal, K p =1.

[0024] If the tire pressure is not normal, 0≤K p <1, the higher or lower the tire pressure is, the smaller K p is, when the tire pressure exceeds the threshold range, K p =0, the rear wheel steering system is closed;

[0025] When the tire pressure is 0, the rear wheel steering system is closed and locked in the current position.

[0026] In an embodiment of the application, the desired rear wheel steering angle obtained according to the front wheel steering angle ratio feedforward includes:

[0027]

[0028] In an embodiment of the application, the desired rear wheel steering angle obtained according to the PI feedback of the center of mass side slip angle deviation and the proportional feedback of the yaw rate deviation includes:

[0029] δ r =k1∫(β-β d )dt+k2(β-β d )+k3(ω r -ω rd )

[0030] In the formula, β is the actual center of mass side slip angle, k1, k2 and k3 are parameters of the PI feedback controller, β d , ω rd are the ideal center of mass side slip angle and yaw rate respectively.

[0031] In a second aspect, the application further provides a multi-mode recognition and switching control system based on the rear wheel steering system, characterized in that it comprises:

[0032] A parameter acquisition module configured to acquire system calculation parameters, obtain a double-critical vehicle speed for working condition recognition through the calculation parameters, and judge whether the current working condition is a low-speed working condition or a medium-high speed working condition,

[0033] The rear wheel steering angle analysis module is configured to obtain the expected rear wheel steering angle according to the front wheel steering angle proportional feedforward, the yaw rate proportional feedback and the tire pressure if the current working condition is judged as the low-speed working condition; if the current working condition is judged as the medium-high speed working condition, it is judged whether the vehicle is in the medium-high speed high adhesion working condition or the medium-high speed low adhesion working condition; if the current working condition is the medium-high speed high adhesion working condition, the expected rear wheel steering angle is obtained according to the front wheel steering angle proportional feedforward; if the current working condition is the medium-high speed low adhesion working condition, the expected rear wheel steering angle is obtained according to the center of mass side slip angle deviation PI feedback and the yaw rate deviation proportional feedback.

[0034] The feedback module is configured to obtain the actual rear wheel steering angle, and perform three-closed-loop feedback control on the motor position, speed and current according to the deviation between the actual rear wheel steering angle and the expected rear wheel steering angle, so that the rear wheel steering actuator can track the expected rear wheel steering angle request in real time under the action of the motor control.

[0035] The main control module is connected with the parameter acquisition module, the rear wheel steering angle analysis module and the feedback module, and is used for executing the above-mentioned multi-mode identification and switching control method based on the rear wheel steering system.

[0036] In a third aspect, the present application further provides a rear wheel steering system, comprising a rack position sensor, a control module and a rear wheel steering actuator, wherein the control module is connected with the rack position sensor and the rear wheel steering actuator.

[0037] The rack position sensor is used for collecting the rack position signal of the steering actuator.

[0038] The control module comprises a steering application layer and a motor control layer, wherein the steering application layer comprises the above-mentioned multi-mode identification and switching control system based on the rear wheel steering system, and is used for realizing the active control of the rear wheel steering angle according to different driving conditions; and the motor control layer is used for outputting signals to the rear wheel steering actuator.

[0039] The rear wheel steering actuator is used for realizing the expected rear wheel steering angle.

[0040] In a fourth aspect, the present application further provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to realize the above-mentioned multi-mode identification and switching control method based on the rear wheel steering system.

[0041] The technical scheme of the embodiment of the present application has at least the following advantages and beneficial effects:

[0042] The method or system provided by the application controls the lateral and yaw motion of the vehicle by actively controlling the rear wheel steering angle, and improves the transient response of the vehicle when turning. When the vehicle is running at high speed, the four-wheel steering system can effectively reduce / eliminate the probability of vehicle side-slip accidents, significantly improve the stability and safety of the vehicle when running at high speed, and further relieve the fatigue of the driver when driving at high speed under various road conditions, especially in rainy and snowy weather. When turning at low speed, the vehicle can reduce the turning radius due to the reverse steering of the front and rear wheels, greatly improving the steering operation maneuverability. At the same time, the vehicle can basically maintain the vehicle mass center side slip angle near zero when turning, and can improve the dynamic response characteristics of the vehicle to the steering wheel input, and can significantly improve the transient response performance indicators of the vehicle yaw angular velocity and lateral acceleration. In addition, the system can adaptively adjust the measures for low adhesion road surface, abnormal tire pressure, and ESP triggering at different vehicle speeds. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0044] Fig. 1 The rear wheel follow-up steering control system provided by the application is shown in the block diagram.

[0045] Fig. 2 The rear wheel follow-up steering control method provided by the application is shown in the flow chart.

[0046] Fig. 3 The four-wheel steering vehicle two-degree-of-freedom equivalent model provided by the application is shown in the diagram. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are some embodiments of the application, but not all the embodiments. The components of the embodiments of the application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0048] The division of the modules appearing in the application is a logical division, and in actual application, another division mode can be used, for example, multiple modules can be combined or integrated in another system, or some features can be ignored or not executed.

[0049] The independent described module or sub-module can be physically separated or not physically separated, can be software implemented or hardware implemented, and part of the module or sub-module can be implemented by software, the function of the part of the module or sub-module is called by a processor, and the other part of the template or sub-module is implemented by hardware, for example, by hardware circuit. In addition, part or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the application.

[0050] Please refer to Figs. 1-3 , the multi-mode recognition and switching control method based on the rear wheel steering system, characterized in that, comprising:

[0051] Obtaining system calculation parameters, obtaining double critical vehicle speeds for working condition recognition through calculation parameters, and judging whether the current working condition is a low-speed working condition or a medium-high speed working condition.

[0052] Among them, as shown in Fig. 3 , a schematic diagram of a two-degree-of-freedom dynamics equivalent model of the whole vehicle is represented, the calculation parameters of the embodiment include the mass m of the whole vehicle, the moment of inertia I z of the whole vehicle around the Z axis, the distances a and b from the center of mass to the front and rear axles, the center of mass height , the tire cornering stiffness k f of the front and rear axles, the wheel radius R, the vehicle body wind area A, and the vehicle body wind resistance coefficient C r , the maximum front wheel angle δ d , the maximum rear wheel angle δ fmax , and the maximum rear wheel angle δ rmax .

[0053] If the current working condition is judged as a low-speed working condition, the expected rear wheel angle is obtained according to the front wheel angle proportional feedforward, the yaw rate proportional feedback, and the tire pressure;

[0054] If the current working condition is judged as a medium-high speed working condition, it is judged whether the vehicle is in a medium-high speed high adhesion working condition or a medium-high speed low adhesion working condition;

[0055] If the current working condition is a medium-high speed high adhesion working condition, the expected rear wheel angle is obtained according to the front wheel angle proportional feedforward;

[0056] If the current working condition is a medium-high speed low adhesion working condition, the expected rear wheel angle is obtained according to the center of mass cornering angle deviation PI feedback and the yaw rate deviation proportional feedback;

[0057] The actual rear wheel angle is obtained, the motor position, speed, and current are controlled by three closed-loop feedback control according to the deviation between the actual rear wheel angle and the expected rear wheel angle, and the rear wheel steering actuator tracks the expected rear wheel angle request in real time under the action of motor control.

[0058] In an example embodiment of the present application, the front wheel and the rear wheel have opposite turning angles in low-speed working conditions, and have the same turning angle in medium-high-speed working conditions, and the critical vehicle speed is defined as the vehicle speed when the rear wheel turning angle is zero.

[0059] The double critical vehicle speeds are used to form a hysteresis interval, and the hysteresis interval comprises:

[0060]

[0061] In the formula, m is the vehicle mass, a and b are the distances from the vehicle mass center to the front and rear axles respectively, L=a+b is the wheelbase of the front and rear axles, k f ,k r are the cornering stiffness of the front and rear tires respectively, V1 and V2 are the critical speeds.

[0062] In an example embodiment of the present application, the judgment of whether the vehicle is in a medium-high-speed high adhesion working condition or a medium-high-speed low adhesion working condition comprises:

[0063] When the vehicle speed V is less than or equal to min(V1, V2), the vehicle is in a low-speed working condition.

[0064] When the vehicle speed V is greater than or equal to max(V1, V2), the vehicle is in a medium-high-speed working condition.

[0065] In an example embodiment of the present application, in a low-speed working condition, a rear wheel turning angle comprehensive control method of front wheel turning angle proportional feedforward and yaw rate proportional feedback is used; at the same time, considering that the vehicle generally does not have the risk of instability at low speed, only the corresponding correction according to the tire pressure is needed, and the rear wheel turning angle input can be represented as:

[0066] δ r =K p (K z1 δ f +K z2 ω r )

[0067] In the formula, δ r is the rear wheel turning angle, K p is a correction coefficient related to the tire pressure, K z1 and K z2 are feedback control gain coefficients, δ f is the front wheel turning angle, and ω r is the yaw rate.

[0068] In the formula, the feedback control gain coefficients are

[0069]

[0070] The steering radius of the vehicle at low speed is smaller, which meets the requirement of reducing the turning radius of the vehicle at low speed steering due to the reverse steering of the front and rear wheels, V x is the longitudinal vehicle speed.

[0071] An example embodiment of the present application also includes the selection of the correction coefficient, including:

[0072] The tire pressure of the rear wheel of the vehicle is obtained, and a standard value and a threshold range are set, and whether the tire pressure of the rear wheel of the vehicle is normal is determined according to the standard value:

[0073] If the tire pressure is normal, K p = 1;

[0074] If the tire pressure is not the same as the standard value, 0≤K p < 1, the higher or lower the tire pressure is, the smaller K p is, and when the tire pressure exceeds the threshold range, K p = 0, the rear wheel steering system is closed;

[0075] When the tire pressure is 0, the rear wheel steering system is closed and locked in the current position.

[0076] In an example embodiment of the present application, under the condition of high speed and high adhesion, the vehicle has no risk of instability, the rear wheel steering system is normally opened, and a rear wheel steering angle control method using front wheel steering angle proportional feedback is adopted, and the rear wheel steering angle input can be expressed as:

[0077]

[0078] In an example embodiment of the present application, under the condition of high speed and low adhesion, the rear wheel steering system is only opened when the vehicle has a risk of instability, and a comprehensive rear wheel steering angle control method using centroid side slip angle deviation PI feedback and yaw rate deviation proportional feedback is adopted, and the rear wheel steering angle input can be expressed as:

[0079] δ r = k1∫(β-β d )dt+k2(β-β d )+k3(ω r -ω rd )

[0080] In the formula, β is the actual centroid side slip angle, k1, k2 and k3 are parameters of the PI feedback controller, β d , ω rd are the ideal centroid side slip angle and yaw rate, respectively.

[0081] Wherein, represents the ideal motion state of the vehicle when it is in steady state driving, and its expression is as follows:

[0082]

[0083] The rear wheel steering control method of high-speed low-attachment working condition comprehensively adopts PI feedback of centroid side slip angle deviation and proportional feedback of yaw rate deviation, and the rear wheel steering system can intervene in emergency before the vehicle is unstable, thereby greatly improving the vehicle handling stability and driving safety.

[0084] The maximum rear wheel steering angle under different vehicle speeds does not exceed the following limit condition:

[0085]

[0086] Wherein, δ rmax The maximum rear wheel steering angle limit is determined by the steering structure, and μ is the average road adhesion coefficient of the two rear wheels. As can be seen from the above formula, the faster the vehicle speed, the smaller the maximum rear wheel steering angle allowed; when the vehicle speed is fast enough (≥ 150km / h), the rear wheel steering system will enter the dead zone, at this time, the rear wheel steering system automatically returns to zero and is locked.

[0087] In the present application, a multi-mode recognition and switching control system based on the rear wheel steering system is also provided, comprising:

[0088] The parameter acquisition module is configured to acquire system calculation parameters, obtain a double-critical vehicle speed for working condition recognition through the calculation parameters, and determine whether the current working condition is a low-speed working condition or a medium-high speed working condition,

[0089] The rear wheel steering angle analysis module is configured to obtain the expected rear wheel steering angle according to the front wheel steering angle proportional feedforward, yaw rate proportional feedback and tire pressure if the current working condition is determined as a low-speed working condition; if the current working condition is determined as a medium-high speed working condition, it is determined whether the vehicle is in a medium-high speed high-attachment working condition or a medium-high speed low-attachment working condition; if the current working condition is a medium-high speed high-attachment working condition, the expected rear wheel steering angle is obtained according to the front wheel steering angle proportional feedforward; if the current working condition is a medium-high speed low-attachment working condition, the expected rear wheel steering angle is obtained according to the centroid side slip angle deviation PI feedback and the yaw rate deviation proportional feedback;

[0090] The feedback module is configured to acquire the actual rear wheel steering angle, and perform three-closed-loop feedback control on the motor position, speed and current according to the deviation between the actual rear wheel steering angle and the expected rear wheel steering angle, so that the rear wheel steering actuator can track the expected rear wheel steering angle request in real time under the action of motor control;

[0091] The main control module is connected with the parameter acquisition module, the rear wheel steering angle analysis module and the feedback module, and is used for executing the multi-mode recognition and switching control method based on the rear wheel steering system.

[0092] In the present application, a rear wheel steering system is also provided, comprising a rack position sensor, a control module and a rear wheel steering actuator, the control module being connected with the rack position sensor and the rear wheel steering actuator;

[0093] The rack position sensor is used to collect the rack position signal of the steering gear;

[0094] The control module comprises a steering application layer and a motor control layer, the steering application layer comprising the above-mentioned multi-mode recognition and switching control system based on the rear wheel steering system, and being used to realize the active control of the rear wheel steering angle according to different driving conditions, and the motor control layer being used to output signals to the rear wheel steering actuator;

[0095] The rear wheel steering actuator is used to realize the desired rear wheel steering angle.

[0096] If the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. The computer software product stored in a storage medium includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various program code storage media.

[0097] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-mode recognition and switching control method based on a rear-wheel steering system, characterized in that: include: Obtain system calculation parameters, obtain dual critical vehicle speeds for working condition identification through calculation parameters, and determine whether the current working condition is a low-speed condition or a medium-high-speed condition. If the current operating condition is judged to be a low-speed condition, the desired rear wheel angle is obtained based on the front wheel angle proportional feedforward, yaw rate proportional feedback, and tire pressure; If the current operating condition is determined to be a medium-high speed operating condition, determine whether the vehicle is currently operating in a medium-high speed high attachment condition or a medium-high speed low attachment condition; If the current working condition is a medium-high speed and high attachment condition, the desired rear wheel angle is obtained based on the front wheel angle ratio feedforward; If the current working condition is a medium-high speed and low attachment condition, the desired rear wheel steering angle is obtained based on the center of mass side slip angle deviation PI feedback and the yaw rate deviation proportional feedback; The actual rear wheel angle is obtained. Based on the deviation between the actual rear wheel angle and the desired rear wheel angle, three closed-loop feedback control of the motor position, speed, and current is performed. The rear wheel steering actuator tracks the desired rear wheel angle request in real time under the action of motor control. The dual critical speeds include: Where m is the vehicle mass, are the distances from the vehicle's center of mass to the front and rear axles, is the wheelbase of the front and rear axles, are the cornering stiffness of the front and rear tires, and is the critical speed; when When , it is low speed condition; when When , it is the medium and high speed working condition, where is the longitudinal speed.

2. The multi-mode recognition and switching control method based on the rear-wheel steering system according to claim 1, characterized in that: The method of obtaining the desired rear wheel steering angle according to the front wheel steering angle proportional feedforward, the yaw rate proportional feedback and the tire pressure includes: Where, is the rear wheel turning angle, is the correction factor related to tire pressure, 、 are all feedback control gain coefficients, is the front wheel turning angle, is the yaw angular velocity.

3. The multi-mode recognition and switching control method based on the rear-wheel steering system according to claim 2, characterized in that: It also includes the selection of correction factors, including: Get the tire pressure of the vehicle's rear wheels, set the standard value and threshold range, and determine whether the tire pressure of the vehicle's rear wheels is normal based on the standard value: If the tire pressure is normal, =1; If the tire pressure is not the same as the standard value, set 0≤ <1, the higher or lower the tire pressure, the The smaller the tire pressure is, the higher the tire pressure will be. =0, turn off the rear wheel steering system; When the tire pressure drops to 0, the rear-wheel steering system is turned off and locked in the current position.

4. The multi-mode recognition and switching control method based on the rear-wheel steering system according to claim 3, characterized in that: The method of obtaining the desired rear wheel steering angle according to the front wheel steering angle ratio feedforward includes: 。 5. The multi-mode recognition and switching control method based on the rear-wheel steering system according to claim 4, characterized in that: Obtaining the desired rear wheel turning angle based on the center of mass sideslip angle deviation PI feedback and the yaw rate deviation proportional feedback includes: Where, is the actual sideslip angle of the center of mass, k1, k2 and k3 are the parameters of the PI feedback controller, are the ideal sideslip angle and yaw rate of the center of mass, respectively.

6. A multi-mode recognition and switching control system based on a rear-wheel steering system, characterized in that: include: a parameter acquisition module configured to acquire system calculation parameters, obtain dual critical vehicle speeds for operating condition identification through the calculation parameters, and determine whether the current operating condition is a low-speed operating condition or a medium-high-speed operating condition; The dual critical speeds include: Where m is the vehicle mass, are the distances from the vehicle's center of mass to the front and rear axles, is the wheelbase of the front and rear axles, are the cornering stiffness of the front and rear tires, and is the critical speed; when When , it is low speed condition; when When , it is the medium and high speed working condition, where is the longitudinal speed; The rear wheel angle analysis module is configured to, if the current operating condition is determined to be a low-speed condition, determine the desired rear wheel angle based on the front wheel angle proportional feedforward, yaw rate proportional feedback, and tire pressure; if the current operating condition is determined to be a medium-high speed condition, determine whether the vehicle is currently operating in a medium-high speed high-adjustment condition or a medium-high speed low-adjustment condition; if the current operating condition is a medium-high speed high-adjustment condition, determine the desired rear wheel angle based on the front wheel angle proportional feedforward; if the current operating condition is a medium-high speed low-adjustment condition, determine the desired rear wheel angle based on the center of mass sideslip angle deviation PI feedback and the yaw rate deviation proportional feedback; a feedback module configured to obtain an actual rear wheel steering angle and perform three-loop feedback control of motor position, speed, and current based on a deviation between the actual rear wheel steering angle and a desired rear wheel steering angle, so that the rear wheel steering actuator tracks the desired rear wheel steering angle request in real time under the control of the motor; A main control module, which is connected to the parameter acquisition module, the rear wheel angle analysis module and the feedback module, and is used to execute the multi-mode recognition and switching control method based on the rear wheel steering system according to any one of claims 1 to 5.

7. A rear wheel steering system, characterized in that: It includes a rack position sensor, a control module and a rear wheel steering actuator, wherein the control module is connected to the rack position sensor and the rear wheel steering actuator; The rack position sensor is used to collect the rack position signal of the steering gear; The control module includes a steering application layer and a motor control layer, wherein the steering application layer includes the multi-mode recognition and switching control system based on the rear-wheel steering system according to claim 6, which is used to achieve active control of the rear wheel steering angle according to different driving conditions, and the motor control layer is used to output signals to the rear-wheel steering actuator; The rear wheel steering actuator is used to achieve a desired rear wheel steering angle.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the multi-mode recognition and switching control method based on the rear-wheel steering system according to any one of claims 1 to 5 is implemented.

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