Control method and control apparatus for transmission ratio of steer-by-wire system, and vehicle

Abstract

A control method for a transmission ratio of a steer-by-wire system, comprising the following steps: determining a first vehicle speed value; determining a current value of a transmission ratio on the basis of the first vehicle speed value; determining whether state information of a steer-by-wire system meets a first preset condition; and on the basis of the determination result and the current value of the transmission ratio, determining a first transmission ratio for determining a final execution value of the transmission ratio of the steer-by-wire system. Also provided are a control apparatus for a transmission ratio of a steer-by-wire system, and a vehicle. By means of such configuration mode, the steer-by-wire system obtains a rational final execution value of the transmission ratio, avoiding the occurrence of safety issues such as a sudden change in the steering feel of a driver or unintended steering of a vehicle under different driving conditions caused by a failure of a vehicle speed signal of the vehicle, such as a sudden change, a deviation or a loss.

Description

Control method and device for transmission ratio of steer-by-wire system and vehicle CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application CN 202311577748.3, filed on November 21, 2023, entitled “Control method, control device and vehicle for transmission ratio of wire-controlled steering system”. The entire contents of the above Chinese patent application are incorporated into this application by reference. Technical Field

[0002] The present invention relates to the technical field of vehicle control, and specifically provides a method for controlling the transmission ratio of a steer-by-wire system, a control device, and a vehicle. Background Art

[0003] The vehicle steering system is a core component of a car, primarily responsible for changing the vehicle's direction of travel. Traditional vehicle steering systems utilize a fixed mechanical transmission ratio, making it difficult to maintain vehicle stability at high speeds. With the advancement of automotive technology, variable transmission ratio online control technology has emerged. This technology adjusts the vehicle's transmission ratio via an electronic control unit, achieving stable steering and efficient power transmission at varying speeds.

[0004] Compared to traditional fixed mechanical transmission ratios, variable-ratio steer-by-wire systems adjust steering response based on vehicle speed, offering greater precision and stability. At low speeds, the steering system can utilize a larger ratio, making steering more agile and effortless, facilitating driver control. At higher speeds, a smaller ratio can be used, providing a more stable steering response and enhancing vehicle stability and handling.

[0005] The accuracy and stability of the vehicle speed signal are crucial to system performance. However, the steering ratio, which varies with vehicle speed, is highly dependent on the speed signal. Failure of the speed signal itself, such as sudden changes, deviations, or loss, can directly lead to sudden changes in steering feel or unintended steering under different driving conditions, impacting the safety of the vehicle and its occupants.

[0006] Accordingly, the art requires a new method, device and vehicle for controlling the transmission ratio of a steer-by-wire system to solve the above problems. Summary of the Invention

[0007] The present invention aims to address the aforementioned technical problem, namely, the problem that the vehicle speed alone cannot meet the high safety requirements of a steer-by-wire system with a variable transmission ratio. To this end, the present invention provides a method for controlling the transmission ratio of a steer-by-wire system. The control method comprises the following steps:

[0008] determining a first vehicle speed value;

[0009] determining a current value of the transmission ratio according to the first vehicle speed value;

[0010] determining whether the state information of the steer-by-wire system satisfies a first preset condition;

[0011] A first transmission ratio is determined based on the judgment result and the current value of the transmission ratio, which is used to determine a final execution value of the transmission ratio of the steer-by-wire system.

[0012] In a specific embodiment of the above-mentioned method for controlling the transmission ratio of a steer-by-wire system, before the step of “determining whether the state information of the steer-by-wire system satisfies a first preset condition”, the control method further includes:

[0013] Acquire status information of the steer-by-wire system, where the status information includes: vehicle speed change rate, steering wheel speed, and yaw angular velocity.

[0014] In a specific implementation of the above-mentioned method for controlling the transmission ratio of the wire-controlled steering system, when the vehicle speed change rate is greater than or equal to a first preset value, the steering wheel 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 wire-controlled steering system meets the first preset condition.

[0015] In a specific embodiment of the above-mentioned method for controlling the transmission ratio of the steer-by-wire system, the step of “determining the first transmission ratio according to the judgment result and the current value of the transmission ratio” specifically includes:

[0016] When the state information of the steer-by-wire system satisfies the first preset condition, determining the first transmission ratio to be a previous value of the transmission ratio;

[0017] When the state information of the steer-by-wire system does not satisfy the first preset condition, the first transmission ratio is determined to be a current value of the transmission ratio.

[0018] In a specific embodiment of the above-mentioned method for controlling the transmission ratio of a steer-by-wire system, after the step of “determining a first transmission ratio based on the determination result and the current value of the transmission ratio” and before the step of “determining a final execution value of the transmission ratio of the steer-by-wire system”, the control method further includes:

[0019] determining a second gear ratio;

[0020] determining whether the first transmission ratio is less than or equal to the second transmission ratio;

[0021] The step of “determining the final execution value of the transmission ratio of the steer-by-wire system” specifically includes:

[0022] When the first transmission ratio is less than or equal to the second transmission ratio, determining the first transmission ratio as a final execution value of the transmission ratio of the steer-by-wire system;

[0023] When the first transmission ratio is greater than the second transmission ratio, the second transmission ratio is determined to be a final execution value of the transmission ratio of the steer-by-wire system.

[0024] In a specific embodiment of the above-mentioned method for controlling the transmission ratio of the steer-by-wire system, the step of “determining the second transmission ratio” specifically includes:

[0025] determining a second vehicle speed value according to the first vehicle speed value and a fourth preset value;

[0026] A transmission ratio threshold is determined according to the second vehicle speed value, where the transmission ratio threshold is the second transmission ratio.

[0027] In a specific embodiment of the above-mentioned method for controlling the transmission ratio of the steer-by-wire system, the step of “determining the first vehicle speed value” specifically includes:

[0028] Get the current vehicle speed value and the previous vehicle speed value to get the vehicle speed change rate;

[0029] determining whether the vehicle speed change rate satisfies a second preset condition;

[0030] If the vehicle speed change rate satisfies a second preset condition, the first vehicle speed value is determined to be the current vehicle speed value; otherwise, the first vehicle speed value is determined to be a fifth preset value.

[0031] In a specific embodiment of the above-mentioned method for controlling the transmission ratio of a steer-by-wire system, before the step of "obtaining a current vehicle speed value and a previous vehicle speed value to obtain a vehicle speed change rate", the control method further includes:

[0032] Obtain vehicle speed signal;

[0033] determining whether the vehicle speed signal is complete;

[0034] If the vehicle speed signal is complete, the acquired vehicle speed is determined to be the current vehicle speed value; otherwise, the current vehicle speed value is determined to be a sixth preset value.

[0035] The present invention also provides a control device for the transmission ratio of a wire-controlled steering system. The control device includes a first determination module, a second determination module, a judgment module, and a third determination module.

[0036] The first determination module is used to determine a first vehicle speed value;

[0037] The second determining module is configured to determine a current value of the transmission ratio according to the first vehicle speed value;

[0038] The judging module is used to judge whether the state information of the steer-by-wire system satisfies a first preset condition;

[0039] The third determination module is used to determine the 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 wire-controlled steering system; the first determination module, the second determination module, the judgment module and the third determination module are connected to implement the control method of the transmission ratio of the wire-controlled steering system as described above.

[0040] The present invention also provides a vehicle including a memory, a processor, and a steer-by-wire system control program stored in the memory and executable on the processor, wherein the processor implements the aforementioned steer-by-wire system control method when executing the steer-by-wire system control program.

[0041] When the above technical solution is adopted, the control method of the transmission ratio of the wire-controlled steering system provided by the present invention obtains a relatively reasonable final execution value of the transmission ratio of the wire-controlled steering system by judging whether the status information of the wire-controlled steering system meets the first preset condition, thereby avoiding the safety problems of sudden changes in the driver's steering feel or unexpected steering of the vehicle under different driving conditions due to the failure of the vehicle speed signal itself, such as sudden changes, deviations or losses, 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 wire-controlled steering system itself, thereby better ensuring the consistency of the driver's steering feel and the controllability of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0043] FIG1 is a flow chart showing the main steps of a method for controlling a transmission ratio of a steer-by-wire system provided by the present invention;

[0044] FIG2 is a flowchart of a method for controlling a transmission ratio of a steer-by-wire system according to an embodiment of the present invention;

[0045] 3 is a flowchart of specific steps for determining the first transmission ratio according to the judgment result and the current value of the transmission ratio provided by the present invention;

[0046] FIG4 is a flowchart of specific steps for determining the second transmission ratio provided by the present invention;

[0047] FIG5 is a flowchart showing the detailed steps of a method for controlling the transmission ratio of a steer-by-wire system according to an embodiment of the present invention;

[0048] FIG6 is a schematic structural diagram of a device for controlling the transmission ratio of a steer-by-wire system provided by the present invention.

[0049] In the picture:

[0050] 310. First determination module;

[0051] 320, second determination module;

[0052] 330. Judgment module;

[0053] 340, third determination module;

[0054] 300. A control device for the transmission ratio of a steer-by-wire system. DETAILED DESCRIPTION

[0055] It should be noted that, in the description of the present invention, terms such as "upper," "lower," "left," "right," "inner," and "outer" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are used solely for ease of description and are not intended to indicate or imply that the relevant devices or components must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, ordinal numbers such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0056] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted" and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0057] 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. For example, the vehicle of the present invention can be an electric vehicle.

[0058] The gear ratio, also known as the steering gear ratio, is the proportional relationship between the input steering angle and the output wheel angle in the steering system. It represents the ratio between the amount of rotation required for the steering operation and the actual amount of wheel rotation.

[0059] Variable-ratio steer-by-wire systems adjust the transmission ratio based on vehicle speed, achieving steering results tailored to varying driving conditions. At low speeds, the variable-ratio steering system can utilize a larger ratio, making steering more flexible and easier for the driver. At higher speeds, however, the steering system can utilize a smaller ratio, providing a more stable steering response and enhancing the vehicle's driving stability and handling. Because the variable transmission ratio is highly dependent on the vehicle speed signal, any failure of the speed signal, such as a sudden change, deviation, or loss, can directly result in a sudden change in steering feel or unintended steering under varying driving conditions. Therefore, it is crucial for steer-by-wire systems to improve the safety and effectiveness of the vehicle speed itself.

[0060] As shown in FIG1 , the present invention proposes a method for controlling the transmission ratio of a steer-by-wire system. The control method comprises the following steps:

[0061] Step S310: determining a first vehicle speed value;

[0062] Step S320: determining a current value of the transmission ratio according to the first vehicle speed value;

[0063] Step S330: determining whether the state information of the steer-by-wire system satisfies a first preset condition;

[0064] Step S340: Determine a first transmission ratio based on the judgment result and the current value of the transmission ratio, which is used to determine a final execution value of the transmission ratio of the steer-by-wire system.

[0065] In this embodiment, by determining whether the status information of the steer-by-wire system satisfies the first preset condition, a relatively reasonable final execution value of the steer-by-wire system transmission ratio is obtained, thereby avoiding the safety issues of sudden changes in the driver's steering feel or unexpected vehicle steering under different driving conditions due to failure of the vehicle speed signal itself, such as mutation, deviation or loss. This reduces the safety requirements of the variable transmission ratio for vehicle speed and improves the safety robustness of the variable transmission ratio design of the steer-by-wire system itself, thereby better ensuring the consistency of the driver's steering feel and the controllability of the vehicle.

[0066] In some examples, in step S320, a transmission ratio curve or a transmission ratio calculation formula may be formulated based on the first vehicle speed value and design requirements. The curve or formula may describe the relationship between the vehicle speed and the steering transmission ratio.

[0067] For example, a linear relationship can be used to calculate the transmission ratio, i.e., the transmission ratio is proportional to the vehicle speed. A nonlinear relationship can also be used to calculate the transmission ratio to better adapt to steering requirements at different vehicle speeds. The transmission ratio can be calculated using a specific algorithm or table lookup method based on the vehicle speed value.

[0068] Furthermore, as shown in FIG2 , before step S330 of “determining whether the state information of the steer-by-wire system satisfies the first preset condition”, the control method may further include:

[0069] Step S321: Acquire status information of the steer-by-wire system, including vehicle speed change rate, steering wheel speed, and yaw angular velocity.

[0070] In this embodiment, the vehicle speed change rate, steering wheel speed, and yaw angular velocity are obtained mainly to realize intelligent control of the steering system to adapt to different driving conditions and driving requirements and provide a better driving experience, safety performance, and handling performance.

[0071] The vehicle's speed change rate refers to the amount of change in vehicle speed per unit time. By monitoring the speed change rate, the steer-by-wire system can adjust the transmission ratio based on the speed change to achieve the desired steering effect under different driving conditions.

[0072] Steering wheel speed refers to the speed at which the driver turns the steering wheel. By monitoring steering wheel speed, the steer-by-wire system can adjust the gear ratio based on the speed of the driver's steering movement, achieving a timely response to the driver's input.

[0073] Yaw rate refers to the rate at which a vehicle rotates about its vertical axis. When a vehicle is navigating a curve or maneuvering, it experiences lateral motion—rotation around its vertical axis. By monitoring yaw rate, steer-by-wire systems can adjust the gear ratio based on the vehicle's lateral motion, providing improved handling and stability.

[0074] Further, when the vehicle speed change rate is greater than or equal to a first preset value, the steering wheel 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.

[0075] In this embodiment, the first preset condition is set as the vehicle speed change rate, steering wheel 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 highly dynamic state, may be performing a rapid steering operation, or may be facing some potential control challenges.

[0076] The first preset value, the second preset value and the third preset value are independent of each other.

[0077] In one possible implementation, the vehicle speed change rate can be calculated by recording the vehicle speed difference between two time points and dividing the difference by the time interval. The vehicle speed can be obtained by a speed sensor provided on the vehicle.

[0078] In one possible implementation, the steering wheel speed may be measured and acquired by a steering sensor or a steering angle sensor of the vehicle. The yaw rate may be measured and acquired by a vehicle dynamics sensor, a gyroscope, or an inertial measurement unit.

[0079] Further, as shown in FIG3 , step S340 of “determining the first transmission ratio according to the judgment result and the current value of the transmission ratio” may specifically include:

[0080] Step S341: when the state information of the steer-by-wire system satisfies a first preset condition, determining that the first transmission ratio is a previous value of the transmission ratio;

[0081] Step S342: When the state information of the steer-by-wire system does not satisfy the first preset condition, determining the first transmission ratio as the current value of the transmission ratio.

[0082] In this embodiment, when the status information of the steer-by-wire system satisfies the first preset condition, that is, the vehicle speed change rate, the steering wheel 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 to be the value of the transmission ratio in the previous calculation cycle can prevent sudden changes in the transmission ratio, thereby preventing sudden changes in the steering feel or unexpected steering, thereby effectively ensuring vehicle safety.

[0083] 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, steering wheel speed and yaw angular velocity does not exceed the corresponding preset value, it means that the vehicle is not in a high dynamic state. In this case, the first transmission ratio is determined to be the current value of the transmission ratio to adapt to the current vehicle speed and improve the driver's control experience.

[0084] Furthermore, as shown in FIG4 and FIG5 , 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:

[0085] Step S343: determining the second transmission ratio;

[0086] Step S344: determining whether the first transmission ratio is less than or equal to the second transmission ratio;

[0087] “Determining the final execution value of the transmission ratio of the steer-by-wire system” may specifically include:

[0088] Step S346: when the first transmission ratio is less than or equal to the second transmission ratio, determining the first transmission ratio as the final execution value of the transmission ratio of the steer-by-wire system;

[0089] Step S347: When the first transmission ratio is greater than the second transmission ratio, the second transmission ratio is determined to be the final execution value of the transmission ratio of the steer-by-wire system.

[0090] In this embodiment, the second transmission ratio is determined to be used to calculate the threshold value of the transmission ratio safety boundary. When the first transmission ratio is less than or equal to the second transmission ratio, that is, the first transmission ratio is less than or equal to the threshold value of the transmission ratio safety boundary, the first transmission ratio is determined to be the final execution value of the transmission ratio of the wire-controlled steering system; when the first transmission ratio is greater than the second transmission ratio, that is, the first transmission ratio is greater than the threshold value of the transmission ratio safety boundary, the threshold value of the transmission ratio safety boundary is determined to be the final execution value of the transmission ratio of the wire-controlled steering system, that is, the second transmission ratio is determined to be the final execution value of the transmission ratio of the wire-controlled steering system.

[0091] In a possible implementation, when the first transmission ratio is greater than the second transmission ratio, the transmission ratio of the steer-by-wire system slowly transitions from the first transmission ratio to the second transmission ratio.

[0092] Further, as shown in FIG4 , step S343 of “determining the second transmission ratio” may specifically include:

[0093] Step S3431: determining a second vehicle speed value according to the first vehicle speed value and a fourth preset value;

[0094] Step S3432: Determine a transmission ratio threshold value according to the second vehicle speed value, where the transmission ratio threshold value is the second transmission ratio.

[0095] In this embodiment, the second gear ratio is determined to calculate a threshold for a gear ratio safety margin. The gear ratio safety margin threshold represents the maximum acceptable value or range of variation for the gear ratio during vehicle maneuvering, ensuring that the vehicle maintains good stability and controllability during maneuvering. If the gear ratio exceeds the safety margin threshold, steering response may become sluggish or inaccurate, potentially affecting the driver's control of the vehicle's direction and increasing the risk of an accident.

[0096] In some examples, in step S3431 , the second vehicle speed value is linearly related to the first vehicle speed value, that is, the second vehicle speed value is proportional to the first vehicle speed value.

[0097] Exemplarily, the fourth preset value may be a constant k, where the second vehicle speed value=k×the first vehicle speed value, wherein k>1.

[0098] Furthermore, as shown in FIG5 , “determining the first vehicle speed value” may specifically include:

[0099] Step S210: obtaining the current vehicle speed value and the previous vehicle speed value to obtain the vehicle speed change rate;

[0100] Step S220: Determine whether the vehicle speed change rate meets a second preset condition;

[0101] Step S230: If the vehicle speed change rate satisfies the second preset condition, the first vehicle speed value is determined to be the current vehicle speed value; otherwise, the first vehicle speed value is determined to be the fifth preset value.

[0102] In this embodiment, when the vehicle speed change rate is less than or equal to a preset change rate, the vehicle speed change rate is determined to satisfy the second preset condition. When the vehicle speed change rate satisfies the second preset condition, i.e., 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 a normal range. The current vehicle speed can be considered valid, and the first vehicle speed value is determined to be the current vehicle speed value.

[0103] In one possible implementation, the second preset condition may be that the rate of increase in vehicle speed, i.e., vehicle acceleration, does not exceed the limit of the vehicle power system, and the rate of decrease in vehicle speed, i.e., vehicle deceleration, does not exceed the limit of the vehicle braking system and tire adhesion coefficient.

[0104] When the speed change rate meets the second preset condition, the vehicle speed is deemed valid, and the first speed value is determined as the current speed value. This effectively calculates the transmission ratio using the valid speed value. If the speed change rate does not meet the second preset condition, the current speed is corrected to within the set speed change rate range, i.e., the fifth preset value is used as the corrected value, and the first speed value is determined as the fifth preset value. Gradient limiting the input speed can minimize the impact of sudden speed changes on vehicle driving safety.

[0105] In some examples, under vehicle deceleration conditions, according to a set vehicle speed change rate, the vehicle speed deceleration may be 10 km / h. For example, if the previous vehicle speed value was 120 km / h, the fifth preset value may be 110 km / h. If the previous vehicle speed value was 110 km / h, the fifth preset value may be 100 km / h. If the previous vehicle speed value was 100 km / h, the fifth preset value may be 90 km / h.

[0106] For example, 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, 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 slowly transition from 0 to 110 km / h.

[0107] Furthermore, as shown in FIG5 , 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:

[0108] Step S110: obtaining a vehicle speed signal;

[0109] Step S120: Determine whether the vehicle speed signal is complete;

[0110] Step S130: If the vehicle speed signal is complete, the acquired vehicle speed is determined to be the current vehicle speed value; otherwise, the current vehicle speed value is determined to be a sixth preset value.

[0111] In this embodiment, by using a complete vehicle speed signal, the accuracy of the transmitted data can be ensured, and the malfunction of the wire-controlled steering system caused by errors or data loss in the vehicle speed signal can be avoided, thereby improving driving safety and vehicle performance.

[0112] In a possible implementation, the vehicle speed signal may be acquired by a sensor or a control unit of the vehicle and transmitted to the steer-by-wire system via a communication system for use.

[0113] To ensure the integrity of the vehicle speed signal, the vehicle communication system can adopt some measures, such as using reliable communication protocols and data transmission mechanisms, performing data verification and error correction, and monitoring the quality and status of the communication link.

[0114] In a possible implementation, if the vehicle speed signal is incomplete, the current vehicle speed value of the steer-by-wire system will slowly transition from the vehicle speed value before the loss to a sixth preset value.

[0115] As shown in FIG6 , the present invention further proposes a control device 300 for a 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 .

[0116] The first determination module 310 is used to determine a first vehicle speed value;

[0117] The second determining module 320 is configured to determine a current value of the transmission ratio according to the first vehicle speed value;

[0118] The judging module 330 is used to judge whether the state information of the steer-by-wire system satisfies a first preset condition;

[0119] The third determination module 340 is used to determine the 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 wire-controlled steering 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 of the wire-controlled steering system transmission ratio as described in the aforementioned method embodiment.

[0120] It should be noted that the structural relationship of each module in FIG6 is only for schematic description and is not used to represent the actual position relationship.

[0121] In a possible embodiment, the control device 300 for the transmission ratio of the wire-controlled steering system may further include a computer-readable storage medium on which a computer program is stored. When the program is executed by the processor, the control method for the transmission ratio of the wire-controlled steering system as described in the aforementioned method embodiment is implemented.

[0122] For the purposes of this specification, a computer-readable medium is any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection having one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM).

[0123] The present invention also provides a vehicle including a memory, a processor, and a steer-by-wire system control program stored in the memory and executable on the processor. When the processor executes the steer-by-wire system control program, the steer-by-wire system transmission ratio control method according to the aforementioned method embodiment is implemented.

[0124] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A method for controlling the transmission ratio of a steer-by-wire system, characterized in that: The control method comprises the following steps: determining a first vehicle speed value; determining a current value of a transmission ratio according to the first vehicle speed value; Determining whether the state information of the steer-by-wire system meets a first preset condition; According to the judgment result and the current value of the transmission ratio, a first transmission ratio is determined, which is used to determine a final execution value of the transmission ratio of the steer-by-wire system.

2. The method for controlling the transmission ratio of a steer-by-wire system according to claim 1, characterized in that: Before the step of "determining whether the state information of the wire control steering system meets the first preset condition", the control method further includes: The state information of the steer-by-wire system is obtained, wherein the state information includes: vehicle speed change rate, steering wheel speed, and yaw angular velocity.

3. The method for controlling the transmission ratio of a steer-by-wire system according to claim 2, characterized in that: When the vehicle speed change rate is greater than or equal to a first preset value, the steering wheel 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.

4. The method for controlling the transmission ratio of a 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 state information of the steer-by-wire system satisfies the first preset condition, determining the first transmission ratio to be a previous value of the transmission ratio; When the state information of the steer-by-wire system does not satisfy the first preset condition, the first transmission ratio is determined to be a current value of the transmission ratio.

5. The method for controlling the transmission ratio of a 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: determining a second gear ratio; determining 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 wire control steering system" specifically includes: When the first transmission ratio is less than or equal to the second transmission ratio, determining the first transmission ratio as a 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, the second transmission ratio is determined as a final execution value of the transmission ratio of the steer-by-wire system.

6. The method for controlling the transmission ratio of a steer-by-wire system according to claim 5, characterized in that: The step of "determining the second transmission ratio" specifically includes: Determining a second vehicle speed value according to the first vehicle speed value and a fourth preset value; A transmission ratio threshold is determined according to the second vehicle speed value, and the transmission ratio threshold is the second transmission ratio.

7. The method for controlling the transmission ratio of a steer-by-wire system according to any one of claims 1 to 6, characterized in that: The step of "determining a first vehicle speed value" specifically includes: Get the current vehicle speed value and the previous vehicle speed value to get the vehicle speed change rate; determining whether the vehicle speed change rate satisfies a second preset condition; If the vehicle speed change rate satisfies the second preset condition, the first vehicle speed value is determined to be the current vehicle speed value; otherwise, the first vehicle speed value is determined to be the fifth preset value.

8. The method for controlling the transmission ratio of a steer-by-wire system according to claim 7, 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: Obtain vehicle speed signal; determining whether the vehicle speed signal is complete; If the vehicle speed signal is complete, the acquired vehicle speed is determined to be the current vehicle speed value; otherwise, the current vehicle speed value is determined to be a sixth preset value.

9. A control device for a transmission ratio of a steer-by-wire system, characterized in that: The control device comprises: A first determining module, used to determine a first vehicle speed value; A second determination module, configured to determine a current value of a transmission ratio according to the first vehicle speed value; A judging module, used for judging whether the state information of the steer-by-wire system satisfies a first preset condition; A third determination module is used to determine a first transmission ratio based on a judgment result and a current value of the transmission ratio, so as to determine a final execution value of the transmission ratio of the wire-controlled steering system; the first determination module, the second determination module, the judgment module and the third determination module are connected to implement the control method of the transmission ratio of the wire-controlled steering system as described in any one of claims 1 to 8.

10. A vehicle, characterized in that: The vehicle comprises: a memory, a processor and a control program of the steer-by-wire system stored in the memory and executable on the processor, and when the processor executes the control program of the steer-by-wire system, the control method of the steer-by-wire system according to any one of claims 1 to 8 is implemented.

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