Rear wheel active steering control method and system and electronic equipment

Abstract

The invention discloses a rear wheel active steering control method and system and electronic equipment, and relates to the technical field of vehicle engineering.The rear wheel active steering control method comprises the steps that the required rear wheel steering angle of current steering of a vehicle is determined, and the vehicle has the rear wheel active steering function; according to the required rear wheel turning angle, the current vehicle speed, the vehicle load, the rear wheel tire pressure, the rear wheel end torque and the vehicle chassis parameters, the required rack force for active steering of the rear wheels is determined; if the required rack force exceeds the rack force threshold value, whether the vehicle is currently in a strong required steering scene or not is judged; if the vehicle is not in the strong demand steering scene currently, the demand rear wheel steering angle is limited to a steering angle boundary value, and the steering angle boundary value is the rear wheel steering angle corresponding to the rack force boundary value at the current vehicle speed; and performing active steering of the rear wheels according to the corner boundary value. By limiting the rear wheel turning angle, the required rack force is limited under the condition of normal steering of the vehicle, and the influence of the generated required rack force on the rear axle assembly during steering according to the required rear wheel turning angle is reduced.

Description

Technical Field

[0001] The present application relates to the field of vehicle engineering technology, and in particular to a rear wheel active steering control method, system and electronic equipment. Background Art

[0002] With the development of technology, people have higher and higher requirements for the operational stability of vehicles while driving, and the active steering technology of vehicles can be an effective means to improve the operational stability of vehicles while driving.

[0003] The vehicle's active steering technology uses an electronic control unit (ECU) and motors to control the mechanical structure to adjust the steering angle of the steering wheels (front wheels, rear wheels or four wheels) in real time, thereby controlling the vehicle's turning radius and optimizing the vehicle's handling performance and driving stability.

[0004] In the active steering of the rear wheels of the vehicle, the motor drives the nut to drive the screw rod to produce axial movement, thereby pushing the steering rod, thereby adjusting the angle of the rear wheel and realizing the rear wheel steering. While the motor pushes the steering rod, it will generate a large rack force, which will have a serious impact on the rear axle assembly of the vehicle (the bridge connecting the two rear wheels). Therefore, how to effectively reduce the impact on the rear axle assembly in the process of realizing rear wheel steering is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the above problems, the present application provides a rear wheel active steering control method, system and electronic device to achieve the purpose of reducing the impact of rear wheel steering on the rear axle assembly. The specific solution is as follows:

[0006] A first aspect of the present application provides a rear wheel active steering control method, the rear wheel active steering control method comprising:

[0007] Determining a required rear wheel steering angle of a vehicle currently being turned, wherein the vehicle is a vehicle having a rear wheel active steering function;

[0008] Determining the required rack force for rear wheel active steering according to the required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters;

[0009] If the required rack force exceeds the rack force threshold, determining whether the vehicle is currently in a strong demand steering scenario;

[0010] If the vehicle is not currently in a strong demand steering scenario, the required rear wheel steering angle is limited to a steering angle boundary value, where the steering angle boundary value is: the rear wheel steering angle corresponding to the rack force boundary value at the current vehicle speed;

[0011] Active rear wheel steering is performed according to the turning angle limit value.

[0012] In a possible implementation, determining the required rear wheel steering angle of the vehicle currently steering includes:

[0013] Obtaining the current vehicle speed, the change angle of the steering wheel, and the change rate of the steering wheel angle;

[0014] The required rear wheel steering angle that matches the current vehicle speed, the change angle of the steering wheel and the change rate of the steering wheel angle is searched in a MAP table, wherein the MAP table is a MAP table corresponding to the current driving mode of the vehicle.

[0015] In a possible implementation, determining the required rack force for rear wheel active steering according to the required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters includes:

[0016] The required rear wheel steering angle, the current vehicle speed, the vehicle load, the rear tire pressure, the rear wheel end torque and the vehicle chassis parameters are substituted into a preset rack force calculation formula to obtain the required rack force for the rear wheel active steering, wherein the preset rack force calculation formula corresponds to the current vehicle speed.

[0017] In a possible implementation, determining whether the vehicle is currently in a strong demand steering scenario includes:

[0018] Detecting the corresponding operating parameters when the driver is driving the vehicle and the activation status of the target function of the vehicle steering;

[0019] If the operating parameters meet the parameter requirements under the strong demand turning scenario and at least one of the target functions is turned on, it is determined that the vehicle is currently in a strong demand turning scenario; otherwise, it is determined that the vehicle is not currently in a strong demand turning scenario.

[0020] In a possible implementation, the method further includes:

[0021] If the required rack force does not exceed the rack force threshold, active rear wheel steering is performed according to the required rear wheel steering angle.

[0022] In a possible implementation, the method further includes:

[0023] If the required rack force exceeds the rack force threshold and the vehicle is currently in a strong steering demand scenario, active rear wheel steering is performed according to the required rear wheel steering angle.

[0024] In a possible implementation, the method further includes:

[0025] Counting the number of times the rear wheel active steering is performed according to the required rear wheel steering angle in a target situation; the target situation is: the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario;

[0026] If the number exceeds the preset number, when the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario, the required rear wheel steering angle is limited to the steering angle boundary value, and the rear wheel active steering is performed according to the steering angle boundary value. The preset number is a preset multiple of the maximum number of times the rack can withstand the excessive rack force, and the preset multiple is a value less than 1 and greater than 0.5.

[0027] A second aspect of the present application provides a rear wheel active steering control system, the rear wheel active steering control system comprising:

[0028] An acquisition unit, used to determine a required rear wheel steering angle of a vehicle currently being turned, wherein the vehicle is a vehicle having a rear wheel active steering function;

[0029] a calculation unit, configured to determine a required rack force for rear wheel active steering according to the required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters, and trigger a judgment unit if the required rack force exceeds a rack force threshold;

[0030] The judging unit is used to judge whether the vehicle is currently in a strong demand turning scenario, and if the vehicle is not currently in a strong demand turning scenario, trigger the limiting unit;

[0031] The limiting unit is used to limit the required rear wheel steering angle to a steering angle boundary value, wherein the steering angle boundary value is: the rear wheel steering angle corresponding to the rack force boundary value at the current vehicle speed;

[0032] A steering unit is used to perform active rear wheel steering according to the turning angle boundary value.

[0033] A third aspect of the present application provides an electronic device, comprising at least one processor and a memory connected to the processor, wherein:

[0034] The memory is used to store computer programs;

[0035] The processor is used to execute the computer program so that the electronic device can implement the rear wheel active steering control method of the first aspect or any implementation method of the first aspect.

[0036] A fourth aspect of the present application provides a computer program product, comprising computer-readable instructions, which, when executed on an electronic device, enables the electronic device to implement the rear-wheel active steering control method of the first aspect or any implementation of the first aspect.

[0037] By means of the above technical solution, the present application provides a rear-wheel active steering control method, system and electronic device. When the vehicle has a steering demand, the method determines the required rack force required for vehicle steering according to the required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters. If the required rack force exceeds the rack force threshold and the vehicle is not currently in a strong demand steering scenario, the required rack force is limited by limiting the rear wheel steering angle to the steering angle boundary value, and the rear wheel active steering is performed according to the steering angle boundary value. In a non-strong demand steering scenario where the required rack force exceeds the rack force threshold, the method limits the required rack force by limiting the rear wheel steering angle, while the vehicle can steer normally, thereby effectively reducing the impact of the required rack force generated when steering according to the required rear wheel steering angle on the rear axle assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0039] Figure 1 A schematic flow chart of a rear wheel active steering control method provided in an embodiment of the present application;

[0040] Figure 2 A schematic diagram of the relationship between vehicle speed and rear wheel turning angle provided in an embodiment of the present application;

[0041] Figure 3 A schematic diagram of the influence of rear wheel steering angle, vehicle speed, vehicle load and rear tire pressure on rack force provided in an embodiment of the present application;

[0042] Figure 4 A schematic diagram of the structure of a rear wheel active steering control system provided in an embodiment of the present application;

[0043] Figure 5 A hardware structure block diagram of an electronic device provided in this application. DETAILED DESCRIPTION

[0044] The following describes the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation method section of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0045] The embodiments of the present application are described below in conjunction with the accompanying drawings. Those skilled in the art will appreciate that, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0046] The terms "including" and "having" and any variations thereof in the specification of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions, so that a process, method, system, product or apparatus that includes a series of units is not necessarily limited to those units, but may include other units not expressly listed or inherent to these processes, methods, products or apparatuses.

[0047] With the rapid development of modern automotive electronic technology, people's requirements for vehicle driving safety, driving comfort, handling stability, energy saving and environmental protection are gradually increasing. The active steering technology of vehicles can be used as an effective means to improve vehicle operational stability and active safety.

[0048] The active steering technology of vehicles can be divided into three types: front-wheel active steering, rear-wheel active steering and four-wheel active steering. Among them, rear-wheel active steering can effectively reduce the turning radius of low-speed vehicles and improve the steering stability of vehicles in high-speed scenarios. However, as a wire-controlled steering, the rear-wheel active steering will generate a large rack force while the motor pushes the tie rod to achieve steering, which has a serious impact on multiple key components of the rear axle assembly (such as bearings), thereby reducing the durability of the rear axle assembly.

[0049] In order to solve the above problems, the embodiment of the present application provides a rear wheel active steering control method. The method limits the rack force by limiting the rear wheel turning angle in some steering scenarios, taking into account the driver's steering needs and rack force, reducing the impact of the rack force on the rear axle assembly, and effectively extending the durability of the rear axle assembly. The rear wheel active steering control method of the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0050] Reference Figure 1 , Figure 1 A flowchart of a rear wheel active steering control method provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, a rear wheel active steering control method provided in an embodiment of the present application may include steps S10 to S14, and these steps are described in detail below.

[0051] S10: Determine a required rear wheel steering angle of the vehicle currently being turned, the vehicle being a vehicle with a rear wheel active steering function.

[0052] Among them, the rear-wheel active steering function refers to the process of steering the vehicle or driving the vehicle, in which the angle and direction of the rear wheels are actively adjusted through the electronic control system, thereby improving the vehicle's handling and stability. When the vehicle is driving at a low speed, the rear wheels deflect in the opposite direction of the front wheels, thereby reducing the vehicle's turning radius and making the vehicle's steering more flexible; when the vehicle is driving at a high speed, the rear wheels deflect in the same direction as the front wheels to improve the vehicle's directional stability and driving safety. The rear wheel turning angle refers to the angle at which the rear wheels deviate from the direction of travel of the vehicle when the vehicle is turning. The required rear wheel turning angle of this embodiment refers to the deviation angle required for the rear wheels to actively steer when the vehicle has a steering demand, so that the vehicle can be steered in response to the steering demand. This embodiment can determine the required rear wheel turning angle of the vehicle's current steering by obtaining relevant parameters for vehicle steering, and the specific process can be as follows:

[0053] Get the current vehicle speed, steering wheel angle change and steering wheel angle change rate; query the required rear wheel steering angle that matches the current vehicle speed, steering wheel angle change and steering wheel angle change rate in the MAP table, where the MAP table corresponds to the vehicle's current driving mode.

[0054] Among them, the change angle of the steering wheel is the steering angle of the steering wheel when the driver is operating the vehicle. It can be directly obtained through the steering wheel angle sensor or indirectly through the torque sensor (when the driver turns the steering wheel, it actually applies torque to the connecting rod of the steering wheel. The torque sensor can detect the size and direction of the torque, and calculate the degree of deformation of the connecting rod to infer the rotation angle of the steering wheel). After the change angle of the steering wheel is obtained, the steering wheel angle change rate is calculated according to the change time of the steering wheel. The steering wheel angle change rate can reflect whether the driver's desire to steer is strong. When the steering wheel angle change rate is too large, it means that the driver has a strong need to steer and wants to steer the vehicle quickly; when the steering wheel angle change rate is too small, it means that the driver's need to steer is not strong and the vehicle can be steered slowly.

[0055] The data correspondence relationship recorded in the MAP table can be determined based on the experimental data of the vehicle. The MAP table records the correspondence between the current vehicle speed, the change angle of the steering wheel, the change rate of the angle of the steering wheel and the required rear wheel angle. After obtaining the current vehicle speed, the change angle of the steering wheel and the change rate of the angle of the steering wheel, it can be directly obtained by querying the MAP table. Since the rear wheel angle when the rear wheel steering is performed in different driving modes of the vehicle is different, such as in the economic mode of the vehicle and the sports mode of the vehicle, the main goal of the economic mode is to reduce energy consumption, the rear wheel angle will be restricted, and unnecessary steering actions will be reduced, thereby reducing energy consumption, while the main goal of the sports mode is driving dynamics and performance, and the rear wheel angle may be increased accordingly to improve the vehicle's handling and response speed. Therefore, the rear wheel angle of the economic mode of the vehicle is smaller than that of the sports mode at the same vehicle speed than that of the sports mode. Therefore, the MAP table in this embodiment corresponds to the driving mode of the vehicle, and provides a rear wheel angle that is more suitable for the driving mode of the vehicle when the rear wheel steering is performed to provide a better driving experience. Of course, under special operating conditions of some vehicles, the electronic control unit can compensate the rear wheel steering angle obtained by MAP query according to the vehicle's real-time data to achieve better rear-wheel active steering control.

[0056] S11. Determine the required rack force for rear wheel active steering according to the required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters.

[0057] Among them, the rack force in the rear-wheel active steering refers to the force generated by the electronic control system or the hydraulic / electric power-assist system in the rear-wheel active steering system to drive the rear-wheel steering mechanism (usually a rack and pinion mechanism) to move. After simulation, testing and analysis, this embodiment determines that the main influencing factors on the rack force may include: rear wheel angle, vehicle speed, vehicle load, rear tire pressure and steering wheel speed, and other influencing factors may include: rear wheel end torque and vehicle chassis parameters. Therefore, this embodiment can calculate the required rack force for the current steering of the vehicle through the rear wheel angle, vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters, where the required rack force is the rack force required for the current steering of the vehicle. Specifically, the calculation process of the required rack force in this embodiment can be specifically as follows:

[0058] The required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters are substituted into a preset rack force calculation formula to obtain the required rack force for rear wheel active steering, wherein the preset rack force calculation formula corresponds to the current vehicle speed.

[0059] Among them, after determining the required rear wheel turning angle of the vehicle's current steering, the vehicle's current speed, vehicle load (the force exerted by the vehicle on the ground), rear tire pressure (air pressure in the rear tire) and rear wheel end torque (the magnitude of the rotational torque on the rear wheel) can be obtained respectively through the corresponding sensors set on the vehicle. The vehicle chassis parameters can refer to: parameters of the basic structure of the vehicle chassis (drive mode, suspension type, chassis height, wheelbase, track, etc.), which can be directly obtained without the need for sensors. After obtaining the values ​​of the above-mentioned influencing factors of the rack force, the preset rack force formula can be brought in to calculate the required rack force of the vehicle's current steering. The preset rack force formula is a formula for calculating the rack force determined during the vehicle's experimental process. In this embodiment, the relevant parameters in the existing rack force calculation formula (such as some parameters independent of the required rear wheel turning angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters) are adjusted by the experimental measurement data of the actual vehicle to obtain the preset rack force formula of this embodiment. The preset rack force formula takes into account the self-aligning moment caused by the lateral force (related to the kingpin roll), the self-aligning moment caused by the longitudinal force (related to the difference in driving force on the left and right sides), the self-aligning moment caused by gravity (kingpin inclination) and the inertia moment.

[0060] Furthermore, the preset rack force formula corresponds to the current speed of the vehicle. Specifically, the preset rack force formula in this embodiment is mainly divided into two types: a low-speed preset rack force formula and a high-speed preset rack force formula.

[0061] S12: If the required rack force exceeds the rack force threshold, determine whether the vehicle is currently in a strong demand steering scenario.

[0062] Among them, the rack force threshold can be determined by the experimental data of the vehicle, and its specific value can be 2500N. At present, the rack force threshold can be determined according to the actual situation (such as the type of vehicle). If the required rack force does not exceed the rack force threshold, it means that the current rack force has little effect on the rear axle assembly of the vehicle, and the vehicle can directly perform rear wheel active steering according to the required rear wheel angle, without limiting the required rack force by adjusting the required rear wheel angle. When the required rack force exceeds the rack force threshold, it means that the current rack force is a large rack force, which has a great impact on the rear axle assembly. It can be selected to adjust the required rear wheel angle before performing rear wheel active steering, thereby limiting the required rack force and reducing the impact on the rear axle assembly. Further, this embodiment not only determines whether to limit the required rear wheel angle only through the rack force threshold, but also considers whether the vehicle is currently in a strong demand steering scenario in order to take into account the steering needs of the driver. It comprehensively determines whether the current steering of the vehicle needs to limit the required rear wheel angle. Therefore, when determining whether the current steering of the vehicle needs to limit the required rear wheel steering angle, this embodiment comprehensively considers the required rack force and the steering scenario of the vehicle.

[0063] S13. If the vehicle is not currently in a strong demand steering scenario, the required rear wheel steering angle is limited to a steering angle boundary value, where the steering angle boundary value is: the rear wheel steering angle corresponding to the rack force boundary value at the current vehicle speed;

[0064] S14. Actively steering the rear wheels according to the turning angle boundary value.

[0065] Among them, the strong demand steering scenario may refer to a driving scenario in which the driver has a strong steering demand. This embodiment can determine whether the driver's steering demand is strong by the corresponding operating parameters when the driver is driving the vehicle and the activation of some functions. Therefore, this embodiment can design a steering model with the function of judging whether the vehicle is in a strong demand steering scenario, which is used to evaluate the necessity of the vehicle's current steering, so as to determine whether the vehicle's current steering needs to limit the required rear wheel angle. The input of the steering model can be the corresponding operating parameters when the driver is driving the vehicle and the activation of the vehicle functions, and directly output the required rear wheel angle that takes into account the durability of the rear axle assembly and the driver's steering expectations, and perform steering. Of course, the steering model can also simultaneously integrate the function of judging whether the rack force exceeds the rack force threshold.

[0066] Specifically, this embodiment can determine whether the vehicle is in a strong demand steering scenario by detecting the corresponding operating parameters when the driver is driving the vehicle and the activation of the target function of the vehicle steering. If the operating parameters meet the parameter requirements of the strong demand steering scenario and at least one target function is turned on, it is determined that the vehicle is currently in a strong demand steering scenario. Otherwise, in other cases (such as the operating parameters meet the parameter requirements of the strong demand steering scenario but the target functions are not turned on), it can be determined that the vehicle is not currently in a strong demand steering scenario. Among them, the target function is a function that needs to be turned on for the vehicle's extreme steering or some extreme working conditions of the vehicle (such as drifting), such as an extreme turning function.

[0067] The rack force boundary value can be determined through actual vehicle test data. The rack force boundary value corresponds to different steering angle boundary values ​​at different vehicle speeds, which means that different steering angle boundary values ​​correspond to different vehicle speeds. Figure 2 As shown in the figure, the horizontal axis is the vehicle speed (negative value indicates reversing condition), and the vertical axis is the corner boundary value. When the vehicle speed is 0, it can represent the on-the-spot turning scene, and the corner boundary value is 3°. When reversing, as the reversing speed increases, the corner boundary value also gradually increases. When the reversing speed is not less than 3km / h, the corner boundary value is fixed at 6°. When the vehicle is driving normally, as the speed increases, the corner boundary value also gradually increases until the speed is not less than 3km / h, the corner boundary value is fixed at 6°. Figure 2 This is only an example to simply illustrate the relationship between vehicle speed and turning angle boundary value. The actual relationship can be more complicated in order to pursue more precise rear wheel active steering control.

[0068] like Figure 3 As shown in the figure, among the main influencing factors, the rear wheel steering angle and vehicle load have positive effects on the rack force, the vehicle speed and rear tire pressure have negative effects on the rack force, and the steering wheel speed has no obvious effect on the rack force. Since the vehicle chassis parameters are basically fixed during the vehicle driving process, the vehicle load and rear tire pressure are not easy to adjust, and the vehicle speed and rear wheel end torque are related to the vehicle driving, which will be affected by the driver's subjective influence. However, compared with other influencing factors, the influence of the steering wheel speed on the rack force is not obvious. Therefore, this embodiment mainly adjusts the rack force by adjusting the rear wheel steering angle. When the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario, the required rear wheel steering angle is limited to the angle boundary value for active rear wheel steering. When the required rear wheel steering angle is the angle boundary value, the required rack force at this time is the rack force boundary value. The angle boundary value can ensure the active steering of the rear wheel, and at the same time, by limiting the required rear wheel steering angle to the angle boundary value, the required rack force can be reduced, thereby reducing the influence of the rack force on the rear axle assembly.

[0069] Furthermore, if the required rack force exceeds the rack force threshold and the vehicle is not currently in a strong steering demand scenario, the required rear wheel angle is limited to the angle boundary value, indicating that the current required rack force is large, but the driver's current steering demand is not strong, then the required rear wheel angle can be limited to reduce the required rack force and reduce the impact on the rear axle assembly; if the required rack force exceeds the rack force threshold and the vehicle is currently in a strong steering demand scenario, it means that although the current required rack force is large and will have a greater impact on the rear axle assembly, the driver's current steering demand is strong, in order to ensure vehicle safety or driver driving safety. Therefore, this embodiment does not limit the rear wheel angle when the required rack force exceeds the rack force threshold and the vehicle is currently in a strong steering demand scenario, then the rear wheels are actively steered according to the required rear wheel angle, and the driver's steering demand is normally responded to.

[0070] Since the life cycle of the rear axle assembly is limited, too many times of large required rack force response will have a great impact on the rear axle assembly. Therefore, when the rear wheel active steering is performed according to the required rear wheel angle in the target situation, this embodiment will record once to count the number of times the rear wheel active steering is performed according to the required rear wheel angle in the life cycle of the rear axle assembly in the target situation. The target situation is that the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario.

[0071] If the number exceeds the preset number, when the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario, the required rear wheel steering angle is limited to the steering angle boundary value, and the rear wheels are actively steered according to the steering angle boundary value.

[0072] The preset number of times can be determined based on the actual vehicle measurement data of the vehicle. The preset number of times is a preset multiple of the maximum number of times the rack can withstand the over-limit rack force, and the preset multiple is a value less than 1 and greater than 0.5. In this embodiment, the preset number of times is less than the maximum number of times the rack can withstand, so that the rack or the rear axle assembly can be left with a bearing space, and the driver can be reminded to perform maintenance in time to prevent direct damage to the rack or the rear axle assembly. The preset number of times must also be greater than 0.5 times the maximum number of times the rack can withstand, so as to increase the service life of the rack or the rear axle assembly.

[0073] When the number of times the rear wheel active steering is performed according to the required rear wheel angle in the target situation is the same as the preset number, it means that the rear axle assembly or the rack is close to the limit of the actual vehicle measurement. Therefore, if in the next target situation, this embodiment will not directly perform the rear wheel active steering according to the required rear wheel angle, but will directly limit the required rear wheel angle to the angle boundary value and perform the rear wheel active steering according to the angle boundary value. Furthermore, after the rack or the rear axle assembly is replaced, the number of times responding to the target situation can be reset to zero and the number of times can be counted again within the life cycle of the rack or the rear axle assembly.

[0074] An embodiment of the present application provides a rear-wheel active steering control method, which determines the required rack force required for vehicle steering based on the required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque, and vehicle chassis parameters when the vehicle has a steering demand. If the required rack force exceeds the rack force threshold and the vehicle is not currently in a strong demand steering scenario, the required rack force is limited by limiting the rear wheel steering angle to the steering angle boundary value, and the rear wheel active steering is performed according to the steering angle boundary value. In a non-strong demand steering scenario where the required rack force exceeds the rack force threshold, this method limits the required rack force when the vehicle can steer normally by limiting the rear wheel steering angle, thereby effectively reducing the impact of the required rack force on the rear axle assembly when steering is performed according to the required rear wheel steering angle.

[0075] A rear wheel active steering control method provided in an embodiment of the present application is introduced above, and a system for executing the above rear wheel active steering control method will be introduced below.

[0076] See also Figure 4 , Figure 4 This is a schematic diagram of the structure of a rear wheel active steering control system provided in an embodiment of the present application. Figure 4 As shown, the rear wheel active steering control system includes:

[0077] The acquisition unit 100 is used to determine the required rear wheel steering angle of the vehicle currently being turned, and the vehicle is a vehicle with a rear wheel active steering function;

[0078] The calculation unit 110 is used to determine the required rack force for the rear wheel active steering according to the required rear wheel steering angle, the current vehicle speed, the vehicle load, the rear tire pressure, the rear wheel end torque and the vehicle chassis parameters, and trigger the judgment unit 120 if the required rack force exceeds the rack force threshold;

[0079] A judging unit 120, used to judge whether the vehicle is currently in a strong demand turning scenario, and if the vehicle is not currently in a strong demand turning scenario, triggering a limiting unit 130;

[0080] A limiting unit 130 is used to limit the required rear wheel steering angle to a steering angle boundary value, where the steering angle boundary value is: the rear wheel steering angle corresponding to the rack force boundary value at the current vehicle speed;

[0081] The steering unit 140 is used to perform active rear wheel steering according to a turning angle boundary value.

[0082] In a possible implementation, the acquisition unit 100 may be specifically configured as follows:

[0083] Get the current vehicle speed, steering wheel angle change and steering wheel angle change rate, and query the required rear wheel steering angle that matches the current vehicle speed, steering wheel angle change and steering wheel angle change rate in the MAP table, which is the MAP table corresponding to the current driving mode of the vehicle.

[0084] In a possible implementation, the computing unit 110 may be specifically configured as follows:

[0085] The required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters are substituted into a preset rack force calculation formula to obtain the required rack force for rear wheel active steering, wherein the preset rack force calculation formula corresponds to the current vehicle speed.

[0086] In a possible implementation, the above-mentioned determination unit 120 may be specifically configured as follows:

[0087] Detect the corresponding operating parameters when the driver is driving the vehicle and the activation status of the target function of the vehicle steering. If the operating parameters meet the parameter requirements under the strong demand steering scenario and at least one target function is turned on, it is determined that the vehicle is currently in the strong demand steering scenario; otherwise, it is determined that the vehicle is not currently in the strong demand steering scenario.

[0088] In a possible implementation, the steering unit 140 may also be configured as:

[0089] If the required rack force does not exceed the rack force threshold, active rear wheel steering is performed based on the required rear wheel turning angle.

[0090] In a possible implementation, the steering unit 140 may also be configured as:

[0091] If the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario, the rear wheels are actively steered according to the required rear wheel angle.

[0092] In a possible implementation, the system of the rear wheel active steering control method may further include a statistical unit:

[0093] a statistical unit, for counting the number of times rear wheel active steering is performed according to a required rear wheel steering angle in a target situation; the target situation is: the required rack force exceeds a rack force threshold and the vehicle is currently in a strong demand steering scenario;

[0094] If the number of times exceeds the preset number of times, the diversion unit 140 is triggered, and the diversion unit 140 can also be configured as:

[0095] When the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario, the required rear wheel steering angle is limited to the angle boundary value, and the rear wheel active steering is performed according to the angle boundary value. The preset number is a preset multiple of the maximum number of times the rack can withstand the excessive rack force, and the preset multiple is a value less than 1 and greater than 0.5.

[0096] The present application also provides an electronic device in an embodiment. Figure 5 As shown, it shows a schematic diagram of the structure of an electronic device suitable for implementing the embodiment of the present application. The electronic device in the embodiment of the present application may include but is not limited to fixed terminals such as mobile phones, laptops, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Figure 5 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0097] like Figure 5 As shown, the electronic device may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 502 or a program loaded from a storage device 508 to a random access memory (RAM) 503. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in the RAM 503. The processing device 501, the ROM 502, and the RAM 503 are connected to each other via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0098] Typically, the following devices may be connected to the I / O interface 505: an input device 506 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 507 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 508 including, for example, a memory card, a hard disk, etc.; and a communication device 509. The communication device 509 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Although Figure 5 An electronic device having various devices is shown, but it should be understood that it is not required to implement or possess all the devices shown. More or fewer devices may be implemented or possessed instead.

[0099] An embodiment of the present application also provides a computer program product including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements any one of the rear-wheel active steering control methods provided in the embodiments of the present application.

[0100] A computer-readable storage medium is also provided in an embodiment of the present application. The storage medium carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any rear-wheel active steering control method provided in the embodiment of the present application.

[0101] It should also be noted that the system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the drawings of the system embodiments provided by the present application, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines.

[0102] Through the description of the above implementation mode, the technicians in the field can clearly understand that the present application can be implemented by means of software plus necessary general hardware, and of course, it can also be implemented by special hardware including special integrated circuits, special CPUs, special memories, special components, etc. In general, all functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be various, such as analog circuits, digital circuits or special circuits. However, for the present application, software program implementation is a better implementation mode in more cases. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a readable storage medium, such as a computer floppy disk, a U disk, a mobile hard disk, a ROM, a RAM, a disk or an optical disk, etc., including a number of instructions to enable a computer device (which can be a personal computer, a training device, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0103] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0104] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, a computer, a training device, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, training device, or data center. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device, a data center, etc. that includes one or more available media integrations. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

[0105] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0106] It is understandable that before using the technical solutions disclosed in the embodiments of the present disclosure, the types, scope of use, usage scenarios, etc. of the personal information involved in the present disclosure should be informed to the user and the user's authorization should be obtained in an appropriate manner in accordance with relevant laws and regulations.

[0107] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A rear wheel active steering control method, characterized in that: The rear wheel active steering control method comprises: Determining a required rear wheel steering angle of a vehicle currently being turned, wherein the vehicle is a vehicle having a rear wheel active steering function; Determining the required rack force for rear wheel active steering according to the required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters; If the required rack force exceeds the rack force threshold, determining whether the vehicle is currently in a strong demand steering scenario; If the vehicle is not currently in a strong demand steering scenario, the required rear wheel steering angle is limited to a steering angle boundary value, where the steering angle boundary value is: the rear wheel steering angle corresponding to the rack force boundary value at the current vehicle speed; Active rear wheel steering is performed according to the turning angle limit value.

2. The rear wheel active steering control method according to claim 1, characterized in that: The determining of the required rear wheel turning angle of the vehicle currently being turned comprises: Obtaining the current vehicle speed, the change angle of the steering wheel, and the change rate of the steering wheel angle; The required rear wheel steering angle that matches the current vehicle speed, the change angle of the steering wheel and the change rate of the steering wheel angle is searched in a MAP table, wherein the MAP table is a MAP table corresponding to the current driving mode of the vehicle.

3. The rear wheel active steering control method according to claim 1, characterized in that: The step of determining the required rack force for the rear wheel active steering according to the required rear wheel steering angle, the current vehicle speed, the vehicle load, the rear tire pressure, the rear wheel end torque and the vehicle chassis parameters comprises: The required rear wheel steering angle, the current vehicle speed, the vehicle load, the rear tire pressure, the rear wheel end torque and the vehicle chassis parameters are substituted into a preset rack force calculation formula to obtain the required rack force for the rear wheel active steering, wherein the preset rack force calculation formula corresponds to the current vehicle speed.

4. The rear wheel active steering control method according to claim 1, characterized in that: The determining whether the vehicle is currently in a strong demand steering scenario includes: Detecting the corresponding operating parameters when the driver is driving the vehicle and the activation status of the target function of the vehicle steering; If the operating parameters meet the parameter requirements under the strong demand turning scenario and at least one of the target functions is turned on, it is determined that the vehicle is currently in a strong demand turning scenario; otherwise, it is determined that the vehicle is not currently in a strong demand turning scenario.

5. The rear wheel active steering control method according to claim 1, characterized in that: Also includes: If the required rack force does not exceed the rack force threshold, active rear wheel steering is performed according to the required rear wheel steering angle.

6. The rear wheel active steering control method according to claim 1, characterized in that: Also includes: If the required rack force exceeds the rack force threshold and the vehicle is currently in a strong steering demand scenario, active rear wheel steering is performed according to the required rear wheel steering angle.

7. The rear wheel active steering control method according to claim 1 or 6, characterized in that: Also includes: Counting the number of times the rear wheel active steering is performed according to the required rear wheel steering angle in a target situation; the target situation is: the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario; If the number exceeds the preset number, when the required rack force exceeds the rack force threshold and the vehicle is currently in a strong demand steering scenario, the required rear wheel steering angle is limited to the steering angle boundary value, and the rear wheel active steering is performed according to the steering angle boundary value. The preset number is a preset multiple of the maximum number of times the rack can withstand the excessive rack force, and the preset multiple is a value less than 1 and greater than 0.

5.

8. A rear wheel active steering control system, characterized in that: The rear wheel active steering control system comprises: An acquisition unit, used to determine a required rear wheel steering angle of a vehicle currently being turned, wherein the vehicle is a vehicle having a rear wheel active steering function; a calculation unit, configured to determine a required rack force for rear wheel active steering according to the required rear wheel steering angle, current vehicle speed, vehicle load, rear tire pressure, rear wheel end torque and vehicle chassis parameters, and trigger a judgment unit if the required rack force exceeds a rack force threshold; The judging unit is used to judge whether the vehicle is currently in a strong demand turning scenario, and if the vehicle is not currently in a strong demand turning scenario, trigger the limiting unit; The limiting unit is used to limit the required rear wheel steering angle to a steering angle boundary value, wherein the steering angle boundary value is: the rear wheel steering angle corresponding to the rack force boundary value at the current vehicle speed; A steering unit is used to perform active rear wheel steering according to the turning angle boundary value.

9. An electronic device, characterized in that: The method comprises at least one processor and a memory connected to the processor, wherein: The memory is used to store computer programs; The processor is used to execute the computer program so that the electronic device can implement the rear wheel active steering control method as described in any one of claims 1 to 7.

10. A computer program product, characterized in that The method comprises computer-readable instructions, and when the computer-readable instructions are executed on an electronic device, the electronic device implements the rear-wheel active steering control method as claimed in any one of claims 1 to 7.

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