Control Method, Control Device and Vehicle for Steering Ratio of Steer-by-Wire System

Abstract

The present invention relates to the technical field of vehicle control, and specifically provides a control method, a control device and a vehicle for the transmission ratio of a steer-by-wire system, aiming to solve the technical problem that the vehicle speed itself cannot meet the relatively high safety requirements of the variable transmission ratio of the steer-by-wire system. For this purpose, the control method provided by the present invention includes the following steps: determining a first vehicle speed value; determining a current value of the transmission ratio according to the first vehicle speed value; judging whether the state information of the steer-by-wire system meets a first preset condition; determining a first transmission ratio according to the judgment result and the current value of the transmission ratio, which is used to determine the final execution value of the transmission ratio of the steer-by-wire system. By this setting method, a relatively reasonable final execution value of the transmission ratio of the steer-by-wire system can be obtained, avoiding the occurrence of safety problems such as sudden changes, deviations or losses in the vehicle speed signal itself, which directly lead to sudden changes in the driver's steering feel or unexpected steering of the vehicle under different driving conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and particularly provides a control method, a control device and a vehicle for the transmission ratio of a steer-by-wire system. Background Art

[0002] The vehicle steering system is one of the core components of an automobile, and its main function is to change the driving direction of the vehicle. The traditional vehicle steering system adopts a fixed mechanical transmission ratio, which is difficult to ensure the stability of the vehicle during high-speed driving. With the development of automotive technology, variable transmission ratio on-line control technology has gradually emerged. This technology can adjust the transmission ratio of the vehicle through an electronic control unit, so as to achieve stable steering and efficient power transmission at different vehicle speeds.

[0003] Compared with the traditional fixed mechanical transmission ratio, the steer-by-wire system with variable transmission ratio is a technology that can adjust the steering effect according to the vehicle speed change. The steer-by-wire system with variable transmission ratio has higher precision and better stability. When driving at low speed, the steering system can adopt a larger transmission ratio, making the steering more flexible and light, which is convenient for the driver to perform steering operations. When driving at high speed, the steering system can adopt a smaller transmission ratio, providing a more stable steering response and enhancing the driving stability and handling performance of the vehicle.

[0004] The accuracy and stability of the vehicle speed signal are crucial for the performance of the system. However, the steering transmission ratio that changes with the vehicle speed highly depends on the vehicle speed signal. The failure of the vehicle speed signal itself, such as sudden change, deviation or loss, will directly bring sudden change of steering feel or unexpected steering under different driving conditions, affecting the safety of the vehicle and the passengers.

[0005] Correspondingly, there is a need in the art for a new control method, a control device and a vehicle for the transmission ratio of a steer-by-wire system to solve the above problems. Summary of the Invention

[0006] The present invention aims to solve the above technical problems, that is, to solve the technical problem that the vehicle speed itself cannot meet the high safety requirements of the variable transmission ratio of the steer-by-wire system. For this purpose, the present invention provides a control method for the transmission ratio of a steer-by-wire system. The control method includes the following steps:

[0007] Determine a first vehicle speed value;

[0008] Determine the current value of the transmission ratio according to the first vehicle speed value;

[0009] Judge whether the state information of the steer-by-wire system meets a first preset condition;

[0010] Determine a first transmission ratio based on the judgment result and the current value of the transmission ratio, which is used to determine the final execution value of the transmission ratio of the steer-by-wire system.

[0011] In the specific implementation manner of the control method for the transmission ratio of the steer-by-wire system, before the step of "judging whether the state information of the steer-by-wire system meets the first preset condition", the control method further includes:

[0012] Obtain the state information of the steer-by-wire system, where the state information includes: vehicle speed change rate, steering wheel rotation speed, and yaw angular velocity.

[0013] In the specific implementation manner of the control method for the transmission ratio of the steer-by-wire system, when the vehicle speed change rate is greater than or equal to a first preset value, and the steering wheel rotation speed is greater than or equal to a second preset value, and the yaw angular velocity is greater than or equal to a third preset value, it is determined that the state information of the steer-by-wire system meets the first preset condition.

[0014] In the specific implementation manner of the control method for the transmission ratio of the steer-by-wire system, the step of "determining a first transmission ratio according to the judgment result and the current value of the transmission ratio" specifically includes:

[0015] When the state information of the steer-by-wire system meets the first preset condition, determine the first transmission ratio as the previous value of the transmission ratio;

[0016] When the state information of the steer-by-wire system does not meet the first preset condition, determine the first transmission ratio as the current value of the transmission ratio.

[0017] In the specific implementation manner of the control method for the transmission ratio of the steer-by-wire system, after the step of "determining a first transmission ratio according to the judgment result and the current value of the transmission ratio" and before the step of "determining the final execution value of the transmission ratio of the steer-by-wire system", the control method further includes:

[0018] Determine a second transmission ratio;

[0019] Judge whether the first transmission ratio is less than or equal to the second transmission ratio;

[0020] The step of "determining the final execution value of the transmission ratio of the steer-by-wire system" specifically includes:

[0021] When the first transmission ratio is less than or equal to the second transmission ratio, determine the first transmission ratio as the final execution value of the transmission ratio of the steer-by-wire system;

[0022] When the first transmission ratio is greater than the second transmission ratio, determine the second transmission ratio as the final execution value of the transmission ratio of the steer-by-wire system.

[0023] In the specific implementation of the above control method for the transmission ratio of the steer-by-wire system, the step of "determining the second transmission ratio" specifically includes:

[0024] Determine a second vehicle speed value according to the first vehicle speed value and a fourth preset value;

[0025] Determine a transmission ratio threshold according to the second vehicle speed value, and the transmission ratio threshold is the second transmission ratio.

[0026] In the specific implementation of the above control method for the transmission ratio of the steer-by-wire system, the step of "determining the first vehicle speed value" specifically includes:

[0027] Obtain the current vehicle speed value and the previous vehicle speed value to obtain a vehicle speed change rate;

[0028] Judge whether the vehicle speed change rate meets a second preset condition;

[0029] If the vehicle speed change rate meets the second preset condition, determine the first vehicle speed value as the current vehicle speed value; otherwise, determine the first vehicle speed value as a fifth preset value.

[0030] Before the step of "obtaining the current vehicle speed value and the previous vehicle speed value to obtain a vehicle speed change rate" in the specific implementation of the above control method for the transmission ratio of the steer-by-wire system, the control method further includes:

[0031] Obtain a vehicle speed signal;

[0032] Judge whether the vehicle speed signal is complete;

[0033] If the vehicle speed signal is complete, determine the obtained vehicle speed as the current vehicle speed value; otherwise, determine the current vehicle speed value as a sixth preset value.

[0034] The present invention also provides a control device for the transmission ratio of a steer-by-wire system. The control device includes a first determination module, a second determination module, a judgment module, and a third determination module.

[0035] The first determination module is used to determine a first vehicle speed value;

[0036] The second determination module is used to determine a current transmission ratio value according to the first vehicle speed value;

[0037] The judgment module is used to judge whether the state information of the steer-by-wire system meets a first preset condition;

[0038] The third determination module is configured to determine a first transmission ratio according to the determination result and the current value of the transmission ratio, and is used to determine the final execution value of the transmission ratio of the steer-by-wire system; the first determination module, the second determination module, the determination module and the third determination module are connected to implement the control method of the transmission ratio of the steer-by-wire system as described above.

[0039] The present invention also provides a vehicle. The vehicle includes a memory, a processor, and a control program of a steer-by-wire system stored on the memory and executable on the processor. When the processor executes the control program of the steer-by-wire system, the control method of the steer-by-wire system as described above is implemented.

[0040] In the case of adopting the above technical solution, the control method of the transmission ratio of the steer-by-wire system provided by the present invention obtains a relatively reasonable final execution value of the transmission ratio of the steer-by-wire system by determining whether the state information of the steer-by-wire system meets a first preset condition, avoiding the occurrence of safety problems such as sudden changes, deviations or losses in the vehicle speed signal itself, which directly lead to sudden changes in the driver's steering feel or unexpected steering of the vehicle under different driving conditions, reducing the safety requirements of the variable transmission ratio for vehicle speed, and improving the safety robustness of the variable transmission ratio design of the steer-by-wire system itself, so as to better ensure the consistency of the driver's steering operation feel and the controllability of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, in which:

[0042] Figure 1 is the main step flow chart of the control method of the transmission ratio of the steer-by-wire system provided by the present invention;

[0043] Figure 2 is the step flow chart of the control method of the transmission ratio of the steer-by-wire system provided by an embodiment of the present invention;

[0044] Figure 3 is the specific step flow chart of determining the first transmission ratio according to the determination result and the current value of the transmission ratio provided by the present invention;

[0045] Figure 4 is the specific step flow chart of determining the second transmission ratio provided by the present invention;

[0046] Figure 5 is the detailed step flow chart of the control method of the transmission ratio of the steer-by-wire system provided by an embodiment of the present invention;

[0047] Figure 6 is the structural schematic diagram of the control device of the transmission ratio of the steer-by-wire system provided by the present invention.

[0048] In the figure:

[0049] 310. The first determination module;

[0050] 320. The second determination module;

[0051] 330. The judgment module;

[0052] 340. The third determination module;

[0053] 300. A control device for the transmission ratio of a steer-by-wire system. Detailed implementation manners

[0054] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the relevant devices or components must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, ordinal numbers such as "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0055] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0056] In the present invention, the vehicle can be an internal combustion engine vehicle or an electric vehicle, which is not limited in the present invention. Exemplarily, the vehicle of the present invention can be an electric vehicle.

[0057] The transmission ratio, that is, the steering transmission ratio, refers to the proportional relationship between the input steering angle and the output wheel rotation angle in the steering system. It represents the ratio between the amount of rotation required for the steering operation and the actual amount of rotation of the wheel.

[0058] A steer-by-wire system with a variable transmission ratio can adjust the transmission ratio according to the vehicle speed change, so as to achieve the steering effect under different driving conditions. When driving at a low speed, the variable transmission ratio steering system can adopt a larger transmission ratio, making the steering more flexible and convenient for the driver to operate. When driving at a high speed, the steering system can adopt a smaller transmission ratio to provide a more stable steering response and enhance the driving stability and handling performance of the vehicle. Since the variable transmission ratio highly depends on the vehicle speed signal, if the vehicle speed signal fails, such as sudden change, deviation or loss, it will directly bring about a sudden change in the steering feel or unexpected steering under different driving conditions. Therefore, it is crucial to improve the safety and effectiveness of the vehicle speed itself in the steer-by-wire system.

[0059] As Figure 1 shown, the present invention proposes a control method for the transmission ratio of a steer-by-wire system. The control method includes the following steps:

[0060] Step S310: Determine the first vehicle speed value;

[0061] Step S320: Determine the current value of the transmission ratio according to the first vehicle speed value;

[0062] Step S330: Judge whether the status information of the steer-by-wire system meets the first preset condition;

[0063] Step S340: Determine the first transmission ratio according to the judgment result and the current value of the transmission ratio, which is used to determine the final execution value of the transmission ratio of the steer-by-wire system.

[0064] In this embodiment, by judging whether the status information of the steer-by-wire system meets the first preset condition, a relatively reasonable final execution value of the transmission ratio of the steer-by-wire system is obtained, avoiding the occurrence of safety problems such as sudden change in the driver's steering feel or unexpected steering of the vehicle directly caused by the failure of the vehicle speed signal itself, such as sudden change, deviation or loss, reducing the safety requirements of the variable transmission ratio for the vehicle speed, and improving the safety robustness of the variable transmission ratio design of the steer-by-wire system itself, so as to better ensure the consistency of the driver's steering operation feel and the controllability of the vehicle.

[0065] In some examples, in step S320, a transmission ratio curve or a calculation formula of the transmission ratio can be formulated according to the first vehicle speed value and the design requirements. The curve or formula can describe the relationship between the vehicle speed and the steering transmission ratio.

[0066] Exemplarily, a linear relationship can be used to calculate the transmission ratio, that is, the transmission ratio is proportional to the vehicle speed. A non-linear relationship can also be adopted to calculate the transmission ratio to better adapt to the steering requirements at different vehicle speeds, and a specific algorithm or look-up table method can be used to calculate the transmission ratio according to the vehicle speed value.

[0067] Further, as Figure 2 shown, before step S330 of "judging whether the state information of the steer-by-wire system meets the first preset condition", the control method may further include:

[0068] Step S321: Obtain the state information of the steer-by-wire system, where the state information includes: vehicle speed change rate, steering wheel rotation speed, and yaw angular velocity.

[0069] In this embodiment, obtaining the vehicle speed change rate, steering wheel rotation speed, and yaw angular velocity is mainly used to achieve intelligent control of the steering system to adapt to different driving conditions and driving demands, and to provide a better driving experience, safety performance, and handling performance.

[0070] The vehicle speed change rate refers to the change in vehicle speed per unit time. By monitoring the vehicle speed change rate, the steer-by-wire system can adjust the transmission ratio according to the speed of the vehicle speed change to achieve the steering effect under different driving conditions.

[0071] The steering wheel rotation speed refers to the speed at which the driver turns the steering wheel. By monitoring the steering wheel rotation speed, the steer-by-wire system can adjust the transmission ratio according to the speed of the driver's steering action to achieve timely response to the driver's operation.

[0072] The yaw angular velocity refers to the speed at which the vehicle rotates around the vertical axis. When the vehicle is driving or maneuvering on a curve, the vehicle will have a lateral movement, that is, the vehicle body rotates around the vertical axis. By monitoring the yaw angular velocity, the steer-by-wire system can adjust the transmission ratio according to the lateral movement state of the vehicle to provide better handling performance and stability.

[0073] Further, when the vehicle speed change rate is greater than or equal to the first preset value, and the steering wheel rotation speed is greater than or equal to the second preset value, and the yaw angular velocity is greater than or equal to the third preset value, it is determined that the state information of the steer-by-wire system meets the first preset condition.

[0074] In this embodiment, the first preset condition is set such that the vehicle speed change rate, steering wheel rotation speed, and yaw angular velocity are all greater than or equal to their respective preset values. When the state information of the steer-by-wire system meets the first preset condition, it means that the vehicle is in a relatively high dynamic state and may be performing a rapid steering operation or facing some potential handling challenges.

[0075] Among them, the first preset value, the second preset value, and the third preset value are independent of each other.

[0076] In a possible implementation manner, the vehicle speed change rate can be calculated by recording the vehicle speed difference between two time points and dividing it by the time interval. Among them, the vehicle speed can be obtained through a speed sensor set on the vehicle.

[0077] In a possible implementation, the steering wheel rotation speed can be measured and obtained by a steering sensor or a steering angle sensor of the vehicle. The yaw angular velocity can be measured and obtained by devices such as a vehicle dynamic sensor, a gyroscope, or an inertial measurement unit.

[0078] Further, as Figure 3 shown, the step S340 of "determining the first transmission ratio according to the judgment result and the current value of the transmission ratio" may specifically include:

[0079] Step S341: When the status information of the steer-by-wire system meets the first preset condition, determine that the first transmission ratio is the previous value of the transmission ratio;

[0080] Step S342: When the status information of the steer-by-wire system does not meet the first preset condition, determine that the first transmission ratio is the current value of the transmission ratio.

[0081] In this embodiment, when the status information of the steer-by-wire system meets the first preset condition, that is, the vehicle speed change rate, the steering wheel rotation speed, and the yaw angular velocity all exceed the corresponding preset values, it indicates that the vehicle is in a relatively high dynamic state. In this case, determining the first transmission ratio as the value of the previous calculation cycle of the transmission ratio can prevent sudden changes in the transmission ratio, thereby preventing sudden changes in the steering feel or unexpected steering, and effectively ensuring vehicle safety.

[0082] When the status information of the steer-by-wire system does not meet the first preset condition, that is, at least one of the vehicle speed change rate, the steering wheel rotation speed, and the yaw angular velocity does not exceed the corresponding preset value, it indicates that the vehicle is not in a relatively high dynamic state. In this case, determining the first transmission ratio as the current value of the transmission ratio can adapt to the current vehicle speed and improve the driver's control experience.

[0083] Further, as Figure 4 and Figure 5 shown, after the step of "determining the first transmission ratio according to the judgment result and the current value of the transmission ratio" and before the step of "determining the final execution value of the transmission ratio of the steer-by-wire system", the control method may further include:

[0084] Step S343: Determine the second transmission ratio;

[0085] Step S344: Judge whether the first transmission ratio is less than or equal to the second transmission ratio;

[0086] "Determining the final execution value of the transmission ratio of the steer-by-wire system" may specifically include:

[0087] Step S346: When the first transmission ratio is less than or equal to the second transmission ratio, determine that the first transmission ratio is the final execution value of the transmission ratio of the steer-by-wire system;

[0088] Step S347: When the first transmission ratio is greater than the second transmission ratio, determine the second transmission ratio as the final execution value of the steer-by-wire system transmission ratio.

[0089] In this embodiment, the second transmission ratio is determined to calculate the threshold value of the transmission ratio safety margin. When the first transmission ratio is less than or equal to the second transmission ratio, that is, when the first transmission ratio is less than or equal to the threshold value of the transmission ratio safety margin, determine the first transmission ratio as the final execution value of the steer-by-wire system transmission ratio; when the first transmission ratio is greater than the second transmission ratio, that is, when the first transmission ratio is greater than the threshold value of the transmission ratio safety margin, determine the threshold value of the transmission ratio safety margin as the final execution value of the steer-by-wire system transmission ratio, that is, determine the second transmission ratio as the final execution value of the steer-by-wire system transmission ratio.

[0090] In a possible implementation manner, when the first transmission ratio is greater than the second transmission ratio, the transmission ratio of the steer-by-wire system will gradually transition from the first transmission ratio to the second transmission ratio.

[0091] Further, as Figure 4 shown, the step S343 of "determining the second transmission ratio" may specifically include:

[0092] Step S3431: Determine a second vehicle speed value according to the first vehicle speed value and a fourth preset value;

[0093] Step S3432: Determine a transmission ratio threshold according to the second vehicle speed value, and the transmission ratio threshold is the second transmission ratio.

[0094] In this embodiment, the second transmission ratio is determined to calculate the threshold value of the transmission ratio safety margin. The threshold value of the transmission ratio safety margin is the maximum acceptable value or change range of the transmission ratio during vehicle operation, which can ensure good stability and controllability of the vehicle during operation. If the transmission ratio exceeds the threshold value of the safety margin, it may cause the steering response to become sluggish or inaccurate, which may affect the driver's control of the vehicle driving direction and increase the risk of accidents.

[0095] In some examples, in step S3431, the second vehicle speed value and the first vehicle speed value are in a linear relationship, that is, the second vehicle speed value is proportional to the first vehicle speed value.

[0096] Exemplarily, the fourth preset value may be a constant k, and the second vehicle speed value = k × the first vehicle speed value, where k > 1.

[0097] Further, as Figure 5 shown, "determining the first vehicle speed value" may specifically include:

[0098] Step S210: Obtain the current vehicle speed value and the previous vehicle speed value to obtain the vehicle speed change rate;

[0099] Step S220: Determine whether the vehicle speed change rate meets the second preset condition;

[0100] Step S230: If the vehicle speed change rate meets the second preset condition, determine the first vehicle speed value as the current vehicle speed value; otherwise, determine the first vehicle speed value as the fifth preset value.

[0101] In this embodiment, when the vehicle speed change rate is less than or equal to the preset change rate, it is determined that the vehicle speed change rate meets the second preset condition. When the vehicle speed change rate meets the second preset condition, that is, the vehicle speed change rate is less than or equal to the preset change rate, it indicates that the vehicle acceleration is small, the vehicle speed changes slowly, the vehicle is in a relatively stable state, or the vehicle speed change is within the normal change range. It can be considered that the current vehicle speed is valid, and the first vehicle speed value is determined as the current vehicle speed value.

[0102] In a possible implementation manner, the second preset condition may be that the rate of increase in vehicle speed, that is, the vehicle acceleration, does not exceed the limit of the vehicle power system, and the rate of decrease in vehicle speed, that is, the vehicle deceleration, does not exceed the limits of the vehicle braking system and the tire adhesion coefficient.

[0103] When the vehicle speed change rate meets the second preset condition, the vehicle speed is regarded as valid, and the first vehicle speed value is determined as the current vehicle speed value, that is, the transmission ratio is calculated using the valid vehicle speed value. When the vehicle speed change rate does not meet the second preset condition, the current vehicle speed is corrected and restricted within the set vehicle speed change rate range. That is, the fifth preset value is the correction value, and the first vehicle speed value is determined as the fifth preset value. Gradient limiting the input vehicle speed can reduce the impact of sudden vehicle speed changes on vehicle driving safety.

[0104] In some examples, in the vehicle deceleration condition, according to the set vehicle speed change rate, the vehicle deceleration can be 10 km / h. For example, if the previous vehicle speed value is 120 km / h and the fifth preset value is 110 km / h. If the previous vehicle speed value is 110 km / h, then the fifth preset value is 100 km / h. If the previous vehicle speed value is 100 km / h, then the fifth preset value is 90 km / h.

[0105] Exemplarily, if the previous vehicle speed value is 120 km / h, the current vehicle speed value is 0, and the fifth preset value is 110 km / h, then the current vehicle speed value is corrected to 110 km / h. For example, the current vehicle speed value of the steer-by-wire system will gradually transition from 0 to 110 km / h.

[0106] Further, as Figure 5 shown, before step S210 of "obtaining the current vehicle speed value and the previous vehicle speed value to obtain the vehicle speed change rate", the control method may further include:

[0107] Step S110: Obtain the vehicle speed signal;

[0108] Step S120: Determine whether the vehicle speed signal is complete;

[0109] Step S130: If the vehicle speed signal is complete, determine that the obtained vehicle speed is the current vehicle speed value; otherwise, determine that the current vehicle speed value is the sixth preset value.

[0110] In this embodiment, by using a complete vehicle speed signal, the accuracy of the transmitted data can be ensured, and the situation of abnormal operation of the steer-by-wire system caused by errors or data loss in the vehicle speed signal can be avoided, thereby improving driving safety and vehicle performance.

[0111] In a possible implementation manner, the vehicle speed signal can be obtained through a vehicle sensor or a control unit and transmitted to the steer-by-wire system for use through a communication system.

[0112] To ensure the integrity of the vehicle speed signal, the vehicle communication system can adopt some measures, such as using a reliable communication protocol and data transmission mechanism for data verification and error correction, and monitoring the quality and status of the communication link, etc.

[0113] In a possible implementation manner, if the vehicle speed signal is incomplete, the current vehicle speed value of the steer-by-wire system will gradually transition from the vehicle speed value before loss to the sixth preset value.

[0114] As Figure 6 shown, the present invention also proposes a control device 300 for the transmission ratio of a steer-by-wire system. The control device 300 includes a first determination module 310, a second determination module 320, a judgment module 330, and a third determination module 340.

[0115] The first determination module 310 is used to determine a first vehicle speed value;

[0116] The second determination module 320 is used to determine the current value of the transmission ratio according to the first vehicle speed value;

[0117] The judgment module 330 is used to judge whether the status information of the steer-by-wire system meets the first preset condition;

[0118] The third determination module 340 is used to determine a first transmission ratio according to the judgment result and the current value of the transmission ratio, and is used to determine the final execution value of the transmission ratio of the steer-by-wire system; the first determination module 310, the second determination module 320, the judgment module 330, and the third determination module 340 are connected to implement the control method for the transmission ratio of the steer-by-wire system as described in the foregoing method embodiment.

[0119] It should be noted that Figure 6 the structural relationship among the modules in

[0120] In a possible implementation manner, the control device 300 for the steering ratio of the steer-by-wire system may further include a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the control method for the steering ratio of the steer-by-wire system as described in the foregoing method embodiment is implemented.

[0121] For the purposes of this specification, a computer-readable medium may be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection (electronic device) having one or more wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM).

[0122] The present invention also provides a vehicle. The vehicle includes a memory, a processor, and a control program for the steer-by-wire system stored on the memory and executable on the processor. When the processor executes the control program for the steer-by-wire system, the control method for the steering ratio of the steer-by-wire system as described in the foregoing method embodiment is implemented.

[0123] So far, the technical solution of the present invention has been described in conjunction with the preferred implementation manners shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific implementation manners. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A control method for the transmission ratio of a steer-by-wire system, characterized in that, the control method includes the following steps: Determine the first vehicle speed value; According to the first vehicle speed value, determine the current value of the transmission ratio; Judge whether the status information of the steer-by-wire system meets the first preset condition; According to the judgment result and the current value of the transmission ratio, determine the first transmission ratio for determining the final execution value of the transmission ratio of the steer-by-wire system; Before the step of "judging whether the status information of the steer-by-wire system meets the first preset condition", the control method further includes: Obtain the status information of the steer-by-wire system, and the status information includes: vehicle speed change rate, steering wheel rotation speed, and yaw angular velocity; When the vehicle speed change rate is greater than or equal to the first preset value, and the steering wheel rotation speed is greater than or equal to the second preset value, and the yaw angular velocity is greater than or equal to the third preset value, it is determined that the status information of the steer-by-wire system meets the first preset condition.

2. The control method for the transmission ratio of the steer-by-wire system according to claim 1, characterized in that, the step of "determining the first transmission ratio according to the judgment result and the current value of the transmission ratio" specifically includes: When the status information of the steer-by-wire system meets the first preset condition, determine that the first transmission ratio is the previous value of the transmission ratio; When the status information of the steer-by-wire system does not meet the first preset condition, determine that the first transmission ratio is the current value of the transmission ratio.

3. The control method for the transmission ratio of the steer-by-wire system according to claim 1, characterized in that, after the step of "determining the first transmission ratio according to the judgment result and the current value of the transmission ratio", and before the step of "determining the final execution value of the transmission ratio of the steer-by-wire system", the control method further includes: Determine the second transmission ratio; Judge whether the first transmission ratio is less than or equal to the second transmission ratio; The step of "determining the final execution value of the transmission ratio of the steer-by-wire system" specifically includes: When the first transmission ratio is less than or equal to the second transmission ratio, determine that the first transmission ratio is the final execution value of the transmission ratio of the steer-by-wire system; When the first transmission ratio is greater than the second transmission ratio, determine that the second transmission ratio is the final execution value of the transmission ratio of the steer-by-wire system.

4. The control method for the transmission ratio of the steer-by-wire system according to claim 3, characterized in that, the step of "determining the second transmission ratio" specifically includes: According to the first vehicle speed value and the fourth preset value, determine the second vehicle speed value; According to the second vehicle speed value, determine the transmission ratio threshold, and the transmission ratio threshold is the second transmission ratio.

5. The control method for the transmission ratio of the steer-by-wire system according to any one of claims 1 to 4, characterized in that, the step of "determining the first vehicle speed value" specifically includes: Obtain the current vehicle speed value and the previous vehicle speed value to obtain the vehicle speed change rate; Judge whether the vehicle speed change rate meets the second preset condition; If the vehicle speed change rate meets the second preset condition, determine that the first vehicle speed value is the current vehicle speed value, otherwise, determine that the first vehicle speed value is the fifth preset value.

6. The control method for the transmission ratio of the steer-by-wire system according to claim 5, Characterized in that, Before the step of "obtaining the current vehicle speed value and the previous vehicle speed value to obtain the vehicle speed change rate", the control method further includes: Obtaining a vehicle speed signal; Judging whether the vehicle speed signal is complete; If the vehicle speed signal is complete, determining that the obtained vehicle speed is the current vehicle speed value; otherwise, determining that the current vehicle speed value is the sixth preset value.

7. A control device for the transmission ratio of a steer-by-wire system Characterized in that, The control device includes: A first determination module for determining a first vehicle speed value; A second determination module for determining the current value of the transmission ratio according to the first vehicle speed value; A judgment module for judging whether the state information of the steer-by-wire system meets a first preset condition; A third determination module for determining a first transmission ratio according to the judgment result and the current value of the transmission ratio, and for determining the final execution value of the transmission ratio of the steer-by-wire system; the first determination module, the second determination module, the judgment module and the third determination module are connected to implement the control method for the transmission ratio of the steer-by-wire system according to any one of claims 1 to 6.

8. A vehicle Characterized in that, The vehicle includes: a memory, a processor, and a control program of a steer-by-wire system stored on the memory and executable on the processor. When the processor executes the control program of the steer-by-wire system, the control method for the transmission ratio of the steer-by-wire system according to any one of claims 1 to 6 is implemented.

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