Variable angle transmission ratio control method and device and vehicle controller

Abstract

The invention provides a variable-angle transmission ratio control method and device and a vehicle controller, relates to the field of vehicle steering control, and provides a variable-angle transmission ratio design, so that the change relation between the vehicle speed and the variable-angle transmission ratio in the corresponding vehicle speed range represented by transmission ratio data corresponding to different vehicle speed ranges is not the same any more. In the actual driving process of the vehicle, after the vehicle controller obtains the driving state information of the vehicle, such as the steering wheel angle and the vehicle speed, the driving state information can be obtained based on the appropriate change relation in the generated transmission ratio data corresponding to different vehicle speed ranges. The ideal variable-angle transmission ratio, namely the target variable-angle transmission ratio, of the vehicle driving to the next time according to the current vehicle speed is accurately determined, the current variable-angle transmission ratio of the vehicle is controlled to be updated to the target variable-angle transmission ratio after the transmission ratio updating condition is determined to be met, and it is guaranteed that the vehicle steering control result is consistent with the steering intention of a driver; and reliable data is provided for other tasks.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle steering control, and more specifically to a variable angle transmission ratio control method, device and vehicle controller. Background Art

[0002] The automobile steering system is the key to ensure the safety of automobile driving. A series of devices that can control the direction of the car according to the driver's intention.

[0003] With the continuous progress of the automobile industry and the deepening of wire control technology, the automobile steering system has gradually developed from several traditional steering systems such as mechanical steering system, hydraulic power steering system and electric power steering system to wire control steering system, which cancels the mechanical connection between the steering wheel and the wheel. By adopting a variable angle transmission ratio (i.e. the ratio of the reverse disc angle to the wheel angle) designed with a constant lateral acceleration gain or a constant yaw rate gain, the steering control of the automobile is achieved to improve the steering performance of the automobile and prevent the steering column from hurting the driver in traffic accidents.

[0004] However, when the vehicle is traveling at medium and low speeds, the variable angle transmission ratio designed with a constant lateral acceleration gain changes too quickly, which is not conducive to the steering performance of the vehicle; when the vehicle is traveling at high speeds, the variable angle transmission ratio designed with a constant yaw rate gain will decrease as the yaw rate gain actually decreases, and the safety of vehicle driving cannot be reliably guaranteed. Summary of the invention

[0005] In view of the above problems, this application provides the following solutions:

[0006] In a first aspect, the present application provides a variable angle transmission ratio control method, the variable angle transmission ratio control method comprising:

[0007] Acquiring driving state information of the vehicle; the driving state information includes a steering wheel angle and a vehicle speed;

[0008] Determine a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data represents a change relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the change relationship corresponding to different vehicle speed ranges is different;

[0009] If the driving state information satisfies the transmission ratio update condition, the current variable angle transmission ratio of the vehicle is controlled to be updated to the target variable angle transmission ratio to achieve the vehicle steering; the transmission ratio update condition indicates whether the update change of the variable angle transmission ratio of the vehicle is consistent with the driver's steering intention. Figure 1 To.

[0010] In a possible implementation, the process of generating the transmission ratio data corresponding to different vehicle speed ranges includes:

[0011] Obtaining a stability constant, a yaw rate gain, and a lateral acceleration gain of the vehicle;

[0012] Determining first transmission ratio data corresponding to a first vehicle speed range based on the stability constant and the lateral acceleration gain;

[0013] determining second transmission ratio data corresponding to a second vehicle speed range based on the stability constant and the yaw rate gain; the second vehicle speed range is smaller than the first vehicle speed range;

[0014] Based on the stability constant and the yaw rate gain, a minimum value of the variable angle transmission ratio of the vehicle is obtained and determined as third transmission ratio data corresponding to a third vehicle speed range; the third vehicle speed range is smaller than the second vehicle speed range;

[0015] The third transmission ratio data, the second transmission ratio data and the first transmission ratio data are used to generate transmission ratio data corresponding to continuously different vehicle speed ranges.

[0016] In a possible implementation, obtaining the yaw rate gain and the lateral acceleration gain of the vehicle includes:

[0017] Acquire a plurality of first candidate gain values ​​of the yaw rate of the vehicle and a plurality of second candidate gain values ​​of the lateral acceleration;

[0018] Controlling the vehicle to travel at different vehicle speeds, and determining maneuverability evaluation indices corresponding to each of the first candidate gain values ​​and each of the second candidate gain values;

[0019] Based on the maneuverability evaluation index, the first candidate gain value and the second candidate gain value that meet the optimization target are selected to correspond to the yaw rate gain and the lateral acceleration gain of the vehicle.

[0020] In a possible implementation, the generating of the transmission ratio data corresponding to consecutive different vehicle speed ranges by using the third transmission ratio data, the second transmission ratio data and the first transmission ratio data includes:

[0021] Generate an initial variable angle transmission ratio curve of the vehicle by using the third transmission ratio data, the second transmission ratio data and the first transmission ratio data corresponding to each vehicle speed range in sequence; the initial variable angle transmission ratio curve represents the changing relationship between different vehicle speeds and different variable angle transmission ratios of the vehicle;

[0022] The initial variable angle transmission ratio curve is subjected to smooth fitting processing, and the variable angle transmission ratio curve after smooth fitting processing is determined as transmission ratio data corresponding to continuous different vehicle speed ranges, so as to determine the target variable angle transmission ratio corresponding to the current vehicle speed by querying the variable angle transmission ratio curve.

[0023] In a possible implementation, determining the target variable angle transmission ratio corresponding to the current vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges includes:

[0024] Determine the transmission ratio data corresponding to the vehicle speed range to which the currently acquired vehicle speed belongs;

[0025] If the vehicle speed belongs to the first vehicle speed range, substituting the lateral acceleration gain of the vehicle and the vehicle speed into the first transmission ratio expression included in the transmission ratio data to obtain a target variable angle transmission ratio corresponding to the vehicle speed;

[0026] If the vehicle speed belongs to the second vehicle speed range, substituting the yaw rate gain of the vehicle and the vehicle speed into the second transmission ratio expression included in the transmission ratio data to obtain a target variable angle transmission ratio corresponding to the vehicle speed;

[0027] If the vehicle speed belongs to a third vehicle speed range, determining the minimum variable angle transmission ratio of the vehicle contained in the transmission ratio data as a target variable angle transmission ratio corresponding to the vehicle speed;

[0028] The second vehicle speed range is smaller than the first vehicle speed range and larger than the third vehicle speed range.

[0029] In a possible implementation, controlling the current variable angle transmission ratio of the vehicle to update to the target variable angle transmission ratio includes:

[0030] According to a fixed update rate, the current variable angle transmission ratio of the vehicle is controlled to be gradually updated to the target variable angle transmission ratio.

[0031] In a possible implementation, the driving state information satisfies a transmission ratio update condition, including any of the following implementations:

[0032] Determining that the steering wheel angle is within a specific angle range; the specific angle range refers to an angle range in the form of an angle less than a threshold value from the steering wheel of the vehicle being in a neutral position;

[0033] Based on a plurality of consecutive steering wheel angles and a plurality of vehicle speeds, it is determined that a change trend of the absolute value of the steering wheel angle is opposite to a change trend of the vehicle speed.

[0034] In a possible implementation, the variable angle transmission ratio control method further includes:

[0035] If the driving state information does not satisfy the transmission ratio update condition, the current variable angle transmission ratio of the vehicle is maintained unchanged.

[0036] In a second aspect, the present application provides a variable angle transmission ratio control device, the variable angle transmission ratio control device comprising:

[0037] An acquisition module, used to acquire driving state information of the vehicle; the driving state information includes a steering wheel angle and a vehicle speed;

[0038] a determination module, configured to determine a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data representing a change relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the change relationship corresponding to different vehicle speed ranges is different;

[0039] a control module, configured to control the current variable angle transmission ratio of the vehicle to be updated to the target variable angle transmission ratio to achieve the vehicle steering if the driving state information satisfies a transmission ratio update condition; the transmission ratio update condition indicates whether the updated change of the variable angle transmission ratio of the vehicle is consistent with the steering intention of the driver; Figure 1 To.

[0040] A third aspect of the present application provides a vehicle controller, which is configured in a vehicle and includes: at least one memory and at least one processor.

[0041] The memory is used to store a plurality of computer instructions;

[0042] The processor is used to execute the multiple computer instructions to implement the following steps:

[0043] Acquiring driving state information of the vehicle; the driving state information includes a steering wheel angle and a vehicle speed;

[0044] Determine a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data represents a change relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the change relationship corresponding to different vehicle speed ranges is different;

[0045] If the driving state information satisfies the transmission ratio update condition, the current variable angle transmission ratio of the vehicle is controlled to be updated to the target variable angle transmission ratio to achieve the vehicle steering; the transmission ratio update condition indicates whether the update change of the variable angle transmission ratio of the vehicle is consistent with the driver's steering intention. Figure 1 To.

[0046] It can be seen that in the variable angle transmission ratio control proposed in the present application, since the variable angle transmission ratio design is proposed in the present application, the change relationship between the vehicle speed and the variable angle transmission ratio in the corresponding speed range represented by the transmission ratio data corresponding to different vehicle speed ranges is no longer the same. In this way, during the actual driving of the vehicle, after the vehicle controller obtains the vehicle's driving state information, such as the steering wheel angle and the vehicle speed, it can accurately determine the ideal variable angle transmission ratio of the vehicle at the next time when it travels at the current vehicle speed based on the appropriate change relationship in the transmission ratio data corresponding to the generated different vehicle speed ranges, that is, the target variable angle transmission ratio; and only after determining that the transmission ratio update conditions are met, the current variable angle transmission ratio of the vehicle will be controlled to be updated to the target variable angle transmission ratio, to ensure that the vehicle steering control result is consistent with the driver's steering intention. Figure 1 Provide reliable data for other tasks. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] 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.

[0048] Figure 1 A schematic flow chart of a variable angle transmission ratio control method proposed in Embodiment 1 of the present application;

[0049] Figure 2 A schematic flow chart of a variable angle transmission ratio control method proposed in Embodiment 2 of the present application;

[0050] Figure 3 A schematic flow chart of a variable angle transmission ratio control method proposed in Embodiment 3 of the present application;

[0051] Figure 4 A schematic diagram showing a comparison of a variable angle transmission ratio curve before and after smooth fitting in a variable angle transmission ratio control method provided in an embodiment of the present application;

[0052] Figure 5 A flow chart of a variable angle transmission ratio control method proposed in Embodiment 4 of the present application;

[0053] Figure 6 A schematic diagram of updating the variable angle transmission ratio for different vehicle speeds and steering wheel angles in a variable angle transmission ratio control method provided in an embodiment of the present application;

[0054] Figure 7 A schematic structural diagram of a variable angle transmission ratio control device provided in an embodiment of the present application;

[0055] Figure 8It is a schematic structural diagram of an optional embodiment of a vehicle controller suitable for the variable angle transmission ratio control method proposed in the present application. DETAILED DESCRIPTION

[0056] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation mode 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. The embodiments of the present application are described below in conjunction with the drawings. It is known to those of ordinary skill in the art 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.

[0057] The terms "first", "second" etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable in appropriate circumstances, and this is only to describe the distinction mode adopted by the objects of the same attributes when describing in the embodiments of the present application. "If" can be interpreted as "at the time of" or "when" or "in response to determining" etc., and can be understood according to the context. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0058] In order to solve the above technical problems existing in the current wire control steering system, that is, when only using a fixed lateral acceleration gain and a fixed yaw rate gain to design the variable angle transmission ratio, it is impossible to take into account the variable angle transmission ratio performance of the vehicle when traveling at medium and low speeds and high speeds, the present application proposes a variable angle transmission ratio control method, which can take into account the variable angle transmission ratio performance of the vehicle when traveling at medium and low speeds and high speeds, improve the transmission of the driver's control intention, reliably improve the safety and comfort of vehicle steering, and after determining the target variable angle transmission ratio of the vehicle at the next time, in order to ensure that it is consistent with the driver's steering intention Figure 1 The present application selectively controls the current variable angle transmission ratio of the vehicle to update to the target variable angle transmission ratio. The variable angle transmission ratio control method of the present application is described in detail below in conjunction with the accompanying drawings.

[0059] Reference Figure 1 , is a flow chart of a variable angle transmission ratio control method proposed in the first embodiment of the present application. The variable angle transmission ratio control method can be executed by a vehicle controller configured in the vehicle. The present application does not limit the composition structure of the vehicle controller, which can be flexibly configured according to the control function. In the embodiment of the present application, Figure 1 As shown, the variable angle transmission ratio control method executed by the vehicle controller may include but is not limited to the following steps:

[0060] Step S101, obtaining driving state information of the vehicle; the driving state information includes a steering wheel angle and a vehicle speed;

[0061] In actual applications, the corresponding types of driving status information generated during the driving process of the vehicle can be collected by sensors configured on the vehicle, or the driving status information of the vehicle can be obtained based on the data collected by the on-board sensors. This application does not limit the implementation method of step S101.

[0062] Based on this, the vehicle speed (i.e., driving speed) can be detected by a vehicle speed sensor (such as a magnetoelectric speed sensor, a Hall-type speed sensor, or a photoelectric speed sensor, etc., and this application does not impose any restrictions on the type of speed sensor), and the detected speed can be sent directly to the vehicle controller through the communication link between the components in the vehicle control system; of course, the vehicle displacement data can also be detected by a displacement sensor and sent to the vehicle controller, and the vehicle controller calculates the vehicle speed based on the displacement data and the corresponding driving time, etc. This application does not impose any restrictions on the method for implementing the speed detection.

[0063] Similarly, the steering wheel angle of the vehicle (i.e., the steering wheel rotation angle) can be determined by the data detected by the angle sensor, angle sensor (such as Hall angle sensor, magnetoresistive angle sensor, photoelectric angle sensor or resistive voltage divider angle sensor, etc.) or torque sensor configured by the vehicle. This application does not limit the type of steering wheel angle sensor and its detection method. The appropriate sensor can be flexibly selected based on actual needs (such as one or more of energy-saving needs, high efficiency needs, stability needs, and accuracy needs, etc.) and the characteristics of each sensor. For example, the rotation circumference of the steering wheel shaft surface detected by the angle sensor is obtained and converted to obtain the steering wheel angle.

[0064] Step S102, determining a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data represents a changing relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the changing relationship corresponding to different vehicle speed ranges is different;

[0065] Combined with the above analysis of the technical solution of the present application, in order to solve the technical problems existing in the wire control steering system, by analyzing the characteristics of the transmission ratio data designed by using a fixed lateral acceleration gain or a fixed yaw rate gain alone, in order to ensure the vehicle's handling performance, handling stability and rollover prevention capability (such as safety), it is proposed to design different transmission ratio data for vehicles traveling in different speed ranges (such as the speed intervals or vehicle gears corresponding to the low speed, medium and low speed and speed driving conditions of the vehicle, etc.), thereby flexibly determining the appropriate change relationship between the vehicle speed and the variable angle transmission ratio within the corresponding speed range, so that the change relationship corresponding to different speed ranges is different and is no longer limited to a certain change relationship. In this way, during the vehicle driving process, as the speed range to which the vehicle speed belongs changes, such as from a low speed driving condition to a medium and low speed driving condition, from a medium and low speed driving condition to a high speed driving condition, etc., the ideal variable angle transmission ratio according to the speed driving to the next time can be accurately determined based on the corresponding relationship corresponding to the speed range, and recorded as the target variable angle transmission ratio.

[0066] It can be seen that the transmission ratio data corresponding to different vehicle speed ranges designed in this application is conducive to taking into account the variable angle transmission ratio performance under medium and low speed conditions and high speed conditions, and ensuring the vehicle's handling stability and safety. This application does not limit the content of the transmission ratio data, and the changing relationship between different vehicle speeds and variable angle transmission ratios can be expressed in any form such as an expression relationship, a chart or a change curve. It should be noted that in the different change relationships corresponding to each vehicle speed range, the influencing factors on the ideal variable angle transmission ratio at different vehicle speeds are inconsistent, so as to achieve the technical effect of improving the transmission of the driver's operating intention and improving the safety and comfort of vehicle steering.

[0067] In combination with the above analysis of the technical problems existing in the wire-controlled steer system, in order to solve the transmission ratio design corresponding to the vehicle speed range of medium and low speeds, the change relationship represented by the transmission ratio data adopts the influencing factor of a fixed lateral acceleration gain, which causes the target variable angle transmission ratio determined by driving within the vehicle speed range to change too quickly, thereby reducing the transmission ratio performance. This application can replace the influencing factor of the lateral acceleration gain of the change relationship corresponding to the vehicle speed range with the yaw angular velocity gain.

[0068] Similarly, since the yaw rate gain decreases as the vehicle speed increases after the vehicle reaches a certain speed, in order to solve the transmission ratio design corresponding to the speed range of the high speed, the change relationship represented by the transmission ratio data adopts the yaw rate gain as an influencing factor, which makes the target variable angle transmission ratio determined for high-speed driving within the speed range lower, resulting in reduced vehicle deceleration efficiency and overly sensitive steering, etc., which is a technical problem contrary to the intention of ensuring vehicle safety when the vehicle is driving at high speed. The present application can replace the influencing factor of the yaw rate gain for the change relationship corresponding to the speed range with the lateral acceleration gain, to ensure that the transmission ratio data designed according to the present application can accurately and reasonably determine the ideal variable angle transmission ratio for the vehicle traveling at the current speed, so as to avoid the traditional wire-controlled steering system reducing the reliability, stability and safety of vehicle steering control due to inappropriate variable angle transmission ratio of vehicle control in different speed ranges.

[0069] It should be understood that the influencing factors of the change relationship corresponding to each vehicle speed range include but are not limited to the lateral acceleration gain and yaw angular velocity gain listed above. Appropriate influencing factors can be configured according to actual needs, and the embodiments of the present application will not be described in detail one by one.

[0070] Step S103, if the vehicle's driving state information satisfies the transmission ratio update condition, the current variable angle transmission ratio of the vehicle is controlled to be updated to the target variable angle transmission ratio to achieve vehicle steering; the transmission ratio update condition indicates that the update change of the vehicle's variable angle transmission ratio is consistent with the driver's steering intention. Figure 1 To.

[0071] In an embodiment of the present application, according to the method described above, after the target variable angle transmission ratio that the currently traveling vehicle needs to execute at the next time is determined in real time, if the current variable angle transmission ratio of the vehicle is updated in real time directly based on the target variable angle transmission ratio, that is, the current variable angle transmission ratio is directly updated to the target variable angle transmission ratio at the next time, it is very likely that the steering wheel angle of the vehicle remains unchanged, but the wheel angle changes due to the real-time update of the variable angle transmission ratio, that is, the vehicle steering control is inconsistent with the driver's steering intention, which is easy to cause liability disputes in traffic accidents.

[0072] In order to solve the above problems, the reliability and accuracy of vehicle steering control are improved, and the change of wheel angle is guaranteed to be consistent with the driver's steering intention. Figure 1 The present application is pre-configured to indicate the updated change of the variable angle transmission ratio of the vehicle and the steering intention of the driver. Figure 1 In this way, after determining the target variable angle transmission ratio at the next time in real time, the present application will first determine whether the driving state information of the vehicle meets the transmission ratio update condition, and only if it meets the transmission ratio update will the variable angle transmission ratio be updated. The present application does not limit the content of the transmission ratio update condition.

[0073] In summary, in order to solve the problem of achieving steering control of a vehicle traveling in different speed ranges based on transmission ratio data representing the same change relationship between vehicle speed and variable angle transmission ratio, since the transmission ratio data is incompatible with the variable angle transmission ratio performance of the vehicle traveling in different speed ranges, the embodiment of the present application proposes a new variable angle transmission ratio design, so that the change relationship represented by the transmission ratio data corresponding to different speed ranges is different. In this way, during the actual driving of the vehicle, after the vehicle controller obtains the vehicle's driving state information, such as the steering wheel angle and the vehicle speed, it can accurately determine the ideal variable angle transmission ratio, i.e., the target variable angle transmission ratio, for the vehicle to travel at the next time according to the current vehicle speed based on the appropriate change relationship in the transmission ratio data corresponding to the generated different speed ranges, and only after determining that the transmission ratio update condition is met, will the current variable angle transmission ratio of the vehicle be controlled to be updated to the target variable angle transmission ratio, so as to ensure that the vehicle steering control result is consistent with the driver's steering intention. Figure 1 It can provide reliable data for other tasks (such as traffic accident responsibility determination or vehicle steering testing).

[0074] Reference Figure 2 , is a flow chart of a variable angle transmission ratio control method proposed in the second embodiment of the present application. This embodiment can describe a possible generation and implementation process of transmission ratio data corresponding to different vehicle speed ranges in the variable angle transmission ratio control method proposed above. This embodiment does not describe in detail other implementation steps of the variable angle transmission ratio control method. Figure 2 As shown, the process of generating transmission ratio data corresponding to different vehicle speed ranges involved in the context of this application may include:

[0075] Step S201, obtaining the stability constant, yaw rate gain and lateral acceleration gain of the vehicle;

[0076] In the actual application of this application, the stability constant of the vehicle involves the ability of the vehicle to restore its original driving state and direction as quickly as possible after encountering external interference during driving, without losing control, sliding or tipping over. This ability is affected by factors such as road conditions, vehicle technical conditions, loading conditions and driving operations. In order to optimize the stability and ride comfort of the vehicle and ensure that the vehicle maintains stable and efficient performance in various driving scenarios, it is necessary to optimize the stability constant related to the steady-state steering characteristics of the vehicle, which can also be called the stability factor.

[0077] Based on this, in a possible implementation, in order to determine the appropriate stability constant of the vehicle, the present application proposes to determine it through a parameter identification method, such as by measuring information such as vehicle speed, yaw rate, lateral acceleration, and steering wheel angle, to identify the stability constant that can ensure the stability and safety of the vehicle. The parameter identification method can be implemented by an inertial measurement unit in the vehicle, and the present application does not describe its implementation process in detail.

[0078] The yaw rate gain and lateral acceleration gain of the vehicle are physical quantities that measure the steady-state response capability of the vehicle. The yaw rate gain can be a physical quantity that is the ratio of the yaw rate to the front wheel turning angle, and the lateral acceleration gain can be a physical quantity that is the ratio of the lateral acceleration to the steering angle of the vehicle. This application can analyze the dynamic characteristics and steady-state response characteristics of the vehicle, and combine the vehicle's maneuverability evaluation indicators in various driving scenarios to predetermine the reasonable gain value of the yaw rate (i.e., yaw rate gain) and the reasonable gain value of the lateral acceleration (i.e., lateral acceleration gain) that can ensure the stability, safety, and steering sensitivity of the vehicle. The implementation method is not limited in this application.

[0079] Step S202, determining first transmission ratio data corresponding to a first vehicle speed range based on a stability constant and a lateral acceleration gain of the vehicle;

[0080] Step S203, determining second transmission ratio data corresponding to a second vehicle speed range based on a stability constant and a yaw rate gain of the vehicle; the second vehicle speed range is smaller than the first vehicle speed range;

[0081] Step S204, based on the stability constant and yaw rate gain of the vehicle, obtaining the minimum value of the variable angle transmission ratio of the vehicle, and determining it as the third transmission ratio data corresponding to the third vehicle speed range; the third vehicle speed range is smaller than the second vehicle speed range;

[0082] In this embodiment, the entire speed range supported by the vehicle can be divided into three levels, which are recorded in sequence from high to low as the first level corresponding to the first speed range, the second level corresponding to the second speed range, and the third level corresponding to the third speed range. The vehicle driving conditions represented in sequence can be high-speed driving conditions, medium-low speed driving conditions, and low-speed driving conditions.

[0083] In order to solve the technical problem that in the scheme of using a constant yaw rate gain for transmission ratio design, during the high-speed driving of the vehicle, the constant yaw rate gain decreases, and the variable angle transmission ratio obtained thereby decreases, resulting in reduced handling stability, stability and anti-rollover capability (i.e. safety) of the vehicle at high speed, the present application is aimed at the high-speed driving of the vehicle, that is, the driving of the vehicle within the first vehicle speed range. When designing the variable angle transmission ratio, a constant yaw rate gain is no longer used, but a constant lateral acceleration gain is used instead.

[0084] Therefore, in order to ensure the handling stability, stability and safety of the vehicle during high-speed driving, the transmission ratio data corresponding to the first vehicle speed range can be determined based on the vehicle's stability constant and lateral acceleration gain, which can be recorded as the first transmission ratio data to distinguish the transmission ratio data corresponding to other vehicle speed ranges. Exemplarily, if the application uses an expression to represent the corresponding relationship between the vehicle speed and the variable angle transmission ratio, the first transmission ratio expression corresponding to the first vehicle speed range, i.e., the first transmission ratio data, can be:

[0085] (1)

[0086] In formula (1), i represents the variable angle transmission ratio, u represents the vehicle speed, and its unit can be m / s (meters per second), K represents the stability constant of the vehicle, l represents the length of the vehicle, and G a Indicates the lateral acceleration gain of the vehicle. Combined with the above analysis, the K and G of the vehicle a It is a fixed value obtained in advance, and this application does not limit its value.

[0087] According to the transmission ratio design idea described above, in order to solve the technical problem that when a fixed lateral acceleration gain is used for transmission ratio design, the variable angle transmission ratio determined thereby changes too quickly when the vehicle is traveling at medium and low speeds, thereby reducing the transmission ratio performance, the present application proposes that when designing a variable angle transmission ratio for the vehicle traveling within the second speed range (i.e., medium and low speed driving conditions), a fixed lateral acceleration gain is no longer used, but a fixed yaw rate gain is used instead. Therefore, in order to ensure the stability of the vehicle during medium and low speed driving, the second transmission ratio data corresponding to the second speed range can be determined based on the vehicle's stability constant and yaw rate gain. Exemplarily, the second transmission ratio expression corresponding to the second speed range, i.e., the second transmission ratio data, can be:

[0088] (2)

[0089] In formula (2), the meanings of i, u, K and l can refer to the description of the corresponding parts of formula (1). r represents the yaw rate gain of the vehicle, which can be obtained in advance according to the acquisition method described in the corresponding part of the context embodiment. r fixed value.

[0090] When the vehicle is traveling at a speed within the third speed range, since the speed is very low, safety and stability can be guaranteed. The present application can directly use the vehicle's minimum transmission force as the third transmission ratio data corresponding to the third speed range. That is to say, when the vehicle is traveling within the third speed range and executes a fixed variable angle transmission ratio, it can reliably meet the vehicle's handling stability, stability, safety and other performance requirements, and ensure the comfort of passengers. The third transmission ratio data can also be determined based on the vehicle's stability constant and yaw rate gain, which can be expressed as:

[0091] (3)

[0092] In formula (3), i, K and G r The meanings of each can refer to the above description. u1 can represent the critical value between the third speed range and the second speed range, which can be calculated by combining the minimum transmission ratio and the transmission ratio expression shown in formula (2). The calculation process is not described in detail in this application. Similarly, for the critical value between the second speed range and the first speed range, denoted as u2, the intersection of the two expressions shown in the above formula (2) and formula (1) can be solved, and the speed corresponding to the intersection can be determined as u2. Therefore, the first speed range can be expressed as: u>u2, the second speed range can be expressed as: u1≤u≤u2, and the third speed range can be expressed as u<u1. It should be noted that the calculation method of u1 and u2 includes but is not limited to the implementation method described in this application, and can also be obtained through experimental testing or set based on experience.

[0093] Step S205: Generate transmission ratio data corresponding to consecutive different vehicle speed ranges by using the third transmission ratio data, the second transmission ratio data and the first transmission ratio data.

[0094] According to the above description of the present application, different transmission ratio design methods are used for different speed ranges of the vehicle, so that the obtained transmission ratio data represents different changing relationships between the vehicle speed and the variable angle transmission ratio. For example, the obtained transmission ratio data corresponding to different speed ranges of the steer-by-wire system applicable to the vehicle can be expressed as follows:

[0095] (4)

[0096] As shown in formula (4), during the actual driving process of the vehicle, the vehicle can ensure safe and stable driving of the vehicle in different speed ranges, and improve riding comfort and safety. According to the method described above, the present application designs corresponding different transmission ratio data for different speed ranges, so as to reasonably and accurately determine the ideal transmission ratio of the vehicle at the next time in the corresponding speed range, so that it can take into account the variable transmission ratio performance under medium and low speeds and high speeds, improve the transmission of the driver's operating intention, and improve the safety and comfort of vehicle steering.

[0097] In some embodiments proposed in the present application, if the transmission ratio data corresponding to different vehicle speed ranges generated in advance are the expressions shown in formula (4), in actual application, after determining the current vehicle speed, it can be substituted into the expression corresponding to the corresponding vehicle speed range to calculate the target variable angle transmission ratio. The implementation process is not described in detail in this application. Optionally, if the transmission ratio data corresponding to different vehicle speed ranges generated in advance are the logical relationship of the expressions shown in formula (4), if the vehicle speed belongs to the first vehicle speed range, the lateral acceleration gain and the vehicle speed of the vehicle are substituted into the first transmission ratio expression contained in the transmission ratio data to obtain the target variable angle transmission ratio corresponding to the vehicle speed; if the vehicle speed belongs to the second vehicle speed range, the yaw rate gain and the vehicle speed are substituted into the second transmission ratio expression contained in the transmission ratio data to obtain the target variable angle transmission ratio corresponding to the vehicle speed; if the vehicle speed belongs to the third vehicle speed range, the minimum value of the vehicle's variable angle transmission ratio contained in the transmission ratio data is determined as the target variable angle transmission ratio corresponding to the vehicle speed. It can be seen that in this optional embodiment, it is necessary to obtain the vehicle's l, K, G as shown in the formula online. a and G r For the required parameters in the parameter acquisition process, please refer to the description of the corresponding part of the context embodiment.

[0098] Reference Figure 3 , is a flow chart of a variable angle transmission ratio control method proposed in Embodiment 3 of the present application. This embodiment can further refine the implementation of the generation process of the transmission ratio data proposed above, such as Figure 3 As shown, the detailed implementation may include:

[0099] Step S301, obtaining the stability constant of the vehicle;

[0100] Step S302, obtaining a plurality of first candidate gain values ​​of the yaw angular velocity of the vehicle and a plurality of second candidate gain values ​​of the lateral acceleration;

[0101] In the embodiment of the present application, the range of the yaw rate and the range of the lateral acceleration of the vehicle can be determined based on the dynamic characteristics and steady-state response characteristics that can be achieved by the actual configuration of the vehicle, and then reasonable candidate gain values ​​can be selected from their respective ranges, such as determining each value included in the value range of the yaw rate of the vehicle as a candidate gain value, or selecting some values ​​from the value range as candidate gain values ​​in combination with experience or historical data; similarly, each candidate gain value of the lateral acceleration of the vehicle can also be selected in this way, but it is not limited to these candidate gain value acquisition methods. For the convenience of description, each candidate gain value of the yaw rate is recorded as a first candidate gain value, and each candidate gain value of the lateral acceleration is recorded as a second candidate gain value.

[0102] Step S303, controlling the vehicle to travel at different vehicle speeds, and determining the maneuverability evaluation index corresponding to each first candidate gain value and each second candidate gain value;

[0103] Step S304, based on the maneuverability evaluation index, selecting a first candidate gain value that meets the optimization target and the first candidate gain value corresponding to the yaw rate gain and the lateral acceleration gain of the vehicle;

[0104] After determining multiple candidate gain values ​​corresponding to the vehicle's yaw rate and lateral acceleration, the optimal solution can be obtained through an optimization method based on the maneuverability evaluation index under different vehicle conditions. That is, the first candidate gain value that meets the optimization goal is determined as the vehicle's yaw rate gain, and the first candidate gain value is determined as the lateral acceleration gain. The present application does not impose any restrictions on the implementation method of the optimization method.

[0105] In a possible implementation, after determining the respective values ​​of the vehicle's yaw rate gain and lateral acceleration gain, for different value combinations, the vehicle is controlled to travel at different speeds through an experimental method, a simulation method, or other simulation methods, and different first candidate gain values ​​or variable angle transmission ratios corresponding to the first candidate gain values ​​are executed to obtain the corresponding maneuverability evaluation index of the vehicle, which is used as an optimization target, and the above candidate gain values ​​are traversed or optimized by an optimization algorithm such as a genetic algorithm to determine the optimal values ​​of the vehicle's yaw rate gain and lateral acceleration gain. Among them, the detected maneuverability evaluation index may include one or more indicators such as trajectory tracking (used to determine the error between the driving path and the expected path, etc.), driver's operating burden, rollover risk, side slip risk, etc. This application does not limit the type of each maneuverability evaluation index and its detection implementation method.

[0106] As analyzed above, the optimization target of the present application may be the optimization target for maneuverability evaluation indicators, with the optimization direction being to reduce factors such as trajectory tracking error, driver's operating burden, rollover risk, and sideslip risk, and according to but not limited to the optimization method described above, the first candidate gain value corresponding to the comprehensive minimum or convergence of the maneuverability evaluation indicators listed above and the first candidate gain value that meets the optimization target are determined to be the vehicle's yaw rate gain, and similarly, the first candidate gain value that meets the optimization target is determined to be the vehicle's lateral acceleration gain.

[0107] Step S305, determining first transmission ratio data corresponding to the first vehicle speed range based on the stability constant and the lateral acceleration gain of the vehicle; determining second transmission ratio data corresponding to the second vehicle speed range based on the stability constant and the yaw rate gain of the vehicle, and determining the minimum value of the variable angle transmission ratio of the vehicle as the third transmission ratio data corresponding to the third vehicle speed range;

[0108] Regarding the implementation process of step S305, reference may be made to the description of the corresponding parts above, such as the description of steps S202 to S204, and this embodiment will not elaborate on the implementation process.

[0109] The yaw rate gain and lateral acceleration gain obtained by the optimization method described above in the present application improve the rationality of the yaw rate gain and lateral acceleration gain used to design the transmission ratio data compared to the implementation method of configuring the yaw rate gain and lateral acceleration gain based on experience or historical data, thereby improving the accuracy and reliability of the transmission ratio data corresponding to different vehicle speed ranges designed accordingly, which is conducive to precise steering control of the vehicle based on the transmission ratio data.

[0110] Step S306, using the third transmission ratio data, the second transmission ratio data and the first transmission ratio data corresponding to each vehicle speed range in sequence, to generate an initial variable angle transmission ratio curve of the vehicle; the initial variable angle transmission ratio curve represents the relationship between different vehicle speeds and different variable angle transmission ratios;

[0111] Step S307, performing smooth fitting processing on the initial variable angle transmission ratio curve, and determining the variable angle transmission ratio curve after smooth fitting processing as the transmission ratio data corresponding to different continuous vehicle speed ranges, so as to determine the target variable angle transmission ratio corresponding to the current vehicle speed by querying the variable angle transmission ratio curve.

[0112] For the transmission ratio data for different vehicle speed ranges determined in this application, such as the expressions corresponding to different vehicle speed ranges expressed by formula (4), the corresponding variable angle transmission ratio curves can be generated, and connected in order from low to high vehicle speeds to obtain the initial variable angle transmission ratio curve for the vehicle. In practical applications, the variable angle transmission ratio curve is not smooth near the critical value between different vehicle speed ranges (such as u1 and u2 above, which can be called transition speed), such as Figure 4 As shown in curve 1 in FIG, when a vehicle runs near this critical value, the motor torque of the vehicle will fluctuate, causing mechanism vibration and energy loss, thereby reducing the vehicle's driving performance.

[0113] In order to improve the above-mentioned problem, the present application proposes to perform smooth fitting processing on the non-smooth initial variable angle transmission ratio curve directly generated, and determine the obtained smooth variable angle transmission ratio curve as the transmission ratio data corresponding to different vehicle speed ranges suitable for the vehicle. Optionally, the smooth fitting processing method may include but is not limited to one or more smooth fitting processing models such as Logistic model (regression analysis model), Gompertz model (a mathematical model used to describe some change processes, to achieve curve modeling), Richards model (a nonlinear growth curve model), Sigmoid model (a logical model, the Sigmoid function used is an S-type function, which can also be called an S-type growth curve), etc., to perform smooth fitting processing on the initial variable angle transmission ratio curve (such as Figure 4 The curve 1) shown in the figure is smoothed by fitting to obtain an ideal variable angle transmission ratio curve close to S-shaped, as shown in Figure 4 As shown in curve 2, this application does not limit the smooth fitting processing method.

[0114] For example, a smooth fitting processing method for the initial variable angle transmission ratio curve based on a Logistic model is used as an example for explanation. The Logistic model can be expressed as:

[0115] (5)

[0116] The present application can control the vehicle to travel at different speeds (at least including the speed around the transition speed, or including multiple speeds in each speed range), determine the initial variable angle transmission ratio of different speeds according to the transmission ratio data shown in formula (4), use the Logistic model to fit these multiple initial variable angle transmission ratios, obtain the target variable angle transmission ratio of the corresponding speed, and generate a smooth variable angle transmission ratio curve by fitting algorithms such as the least squares method and the gradient descent method. The parameters A, B, a and b in formula (5) can be obtained by fitting and calculating multiple sets of simulation or test data to reduce the mean square error / variance, avoid overfitting and underfitting, and ensure that the variable angle transmission ratio curve after smooth fitting is accurate and reliable. It should be understood that if the initial variable angle transmission ratio curve is a smooth curve, it can be directly used as the required variable angle transmission ratio curve without performing the smooth fitting processing operation of the above curve.

[0117] It can be seen that according to the transmission ratio design scheme described above in the embodiment of the present application, a smooth variable angle transmission ratio curve is obtained for vehicle steering control, which can effectively improve the vehicle's handling stability. During the actual driving of the vehicle, after determining the current vehicle speed, the variable angle transmission ratio curve can be directly queried to quickly and accurately determine the target variable angle transmission ratio of the vehicle at the next time, thereby realizing vehicle steering control and ensuring the vehicle's steering sensitivity, stability and control efficiency.

[0118] Reference Figure 5 , is a flow chart of a variable angle transmission ratio control method proposed in the fourth embodiment of the present application. This embodiment can provide a detailed description of the variable angle transmission ratio update process in the variable angle transmission ratio control method proposed in the above embodiments, such as Figure 5 As shown, the variable angle transmission ratio control method proposed in this embodiment may include:

[0119] Step S501, obtaining driving state information of the vehicle; the driving state information includes a steering wheel angle and a vehicle speed;

[0120] Step S502, determining a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data represents a changing relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the changing relationship corresponding to different vehicle speed ranges is different;

[0121] Regarding the implementation method of step S501 and step S502, reference may be made to the description of the corresponding part of the above embodiment. In some embodiments, for the transmission ratio design scheme proposed in this application, a fixed transmission ratio is used at low speed, a yaw rate gain is used to design the transmission ratio at medium and low speeds, and a lateral acceleration gain is used to design the transmission ratio at high speeds. Of course, in order to improve the vehicle handling stability, the designed variable angle transmission ratio curve can be smoothly fitted to obtain the actual required smooth variable angle transmission ratio curve, and the implementation process is not described in detail in this embodiment.

[0122] Step 503, determining whether the driving state information of the vehicle meets the transmission ratio update condition, if so, proceeding to step S504, if not, executing step S505;

[0123] Step S504, controlling the current variable angle transmission ratio of the vehicle to be gradually updated to the target variable angle transmission ratio at a fixed update rate;

[0124] Step S505, maintaining the current variable angle transmission ratio of the vehicle unchanged.

[0125] Combined with the above description of the transmission ratio update conditions, in practical applications, the wheel steering and the driver's steering intention need to be Figure 1 Therefore, in the actual driving process of the vehicle, the variable angle transmission ratio will not be updated in real time. For example, the variable angle transmission ratio of the vehicle is controlled to change in real time according to the above variable angle transmission ratio curve. In order to ensure the handling stability and safety of the vehicle, this application proposes a new variable angle transmission ratio update strategy to ensure that the update change of the vehicle's variable angle transmission ratio is consistent with the driver's steering intention. Figure 1 To.

[0126] Based on this, the present application can determine whether the transmission ratio update condition is currently met before executing the determined target variable angle transmission ratio based on the continuously obtained driving status information. If it is met, it means that the current variable angle transmission ratio needs to be updated at this time. In order to prevent the variable angle transmission ratio from changing suddenly, in the variable angle transmission ratio update strategy proposed in the present application, the current variable angle transmission ratio can be controlled to be gradually updated to the target variable angle transmission ratio according to the pre-configured fixed update rate. The fixed update rate refers to how many variable angle transmission ratios are updated per unit time, such as the variable angle transmission ratio increases or decreases by 2, 5, or 8 per second, etc. The present application does not limit the value of the fixed update rate, which can be determined according to actual needs.

[0127] Exemplarily, the fixed update rate of the vehicle's variable angle transmission ratio, which can only increase or decrease by 5 per second, is used as an example to illustrate. If the vehicle's current variable angle transmission ratio is 10, and the target variable angle transmission ratio for the next time is determined according to the method described above, it is 20. When the transmission ratio update conditions are met, the current variable angle transmission ratio of 10 can be controlled to be updated to 15 after the first second, and to 20 after the second second. Compared with the real-time update method of directly updating the current variable angle transmission ratio from 10 to 20 at the first second, the linear update method of the transmission ratio proposed in the present application avoids excessively rapid changes in the variable angle transmission ratio, ensures the transmission ratio performance of the vehicle, and improves the vehicle's handling stability.

[0128] Based on this, Figure 6 In the acceleration process shown in Figure (a), the vehicle speed increases with time, and the steering wheel of the vehicle is turned synchronously to change the steering wheel angle, such as Figure 6 The steering wheel angle shown in Figure (b) changes with time, but is not limited to Figure 6 The change curve of the steering wheel angle shown in Figure (b) can be used to determine the change relationship between vehicle speed and steering wheel angle through time alignment. Figure 6 In the driving scenarios shown in Figures (a) and (b), during the control of the variable angle transmission ratio of the vehicle, when it is determined that the transmission ratio update conditions are met, the vehicle is controlled according to Figure 6 The transmission ratio update strategy represented by the broken line shown by the solid line in (c) linearly updates the variable angle transmission ratio of the vehicle, that is, controls the current variable angle transmission ratio of the vehicle to be gradually updated to the target variable angle transmission ratio. Compared with the smooth fitting transmission ratio curve designed in this application, Figure 6 The real-time update curve shown by the dotted line in (c) represents the real-time update strategy of the variable angle transmission ratio. No matter in which vehicle range the vehicle is traveling, it can reliably avoid the variable angle transmission ratio from changing too quickly, thereby ensuring the vehicle's handling stability.

[0129] Of course, if it is currently determined that the transmission ratio update condition is not met, the present application will not update the variable angle transmission ratio, but will control the variable angle transmission ratio to maintain a constant value, maintaining the current variable angle transmission ratio unchanged, such as Figure 6 The horizontal line segment in the broken line shown in Figure (c) (such as the line segment corresponding to the same variable angle transmission ratio from 3.3 to 4.7) corresponds to the driving time period. Although the designed ideal variable angle transmission ratio will increase, if the transmission ratio update condition is not met at this time, the application will not actually update the variable angle transmission ratio to ensure that it is consistent with the driver's steering intention. Figure 1 To.

[0130] It should be understood that after executing step S504 and step S505, it is possible to continue to determine whether the newly acquired driving state information meets the transmission ratio update condition, and further determine whether it is necessary to linearly update the target variable angle transmission ratio at the next time. Since step S501 can be executed in real time, the target variable angle transmission ratio at the next time is determined in real time for the vehicle speed acquired in real time. In this determination process, it can be synchronously determined whether the transmission ratio update condition is met to improve control efficiency.

[0131] In some embodiments proposed in this application, during the actual driving process of the vehicle, when the vehicle speed decreases, the real-time variable angle transmission ratio decreases, and the corresponding wheel angle increases, and when the steering wheel absolute value increases, the wheel angle also increases. It can be seen that when the absolute value change trend of the vehicle's steering wheel angle is opposite to the vehicle speed change trend, it means that the update change of the variable angle transmission ratio at this time is related to the driver's steering intention. Figure 1 Of course, if the steering wheel is near the neutral position, the steering wheel angle is 0 and the vehicle is driving in a straight line, it is consistent with the driver's steering intention. Figure 1 The vehicle's variable angle transmission ratio can be updated.

[0132] It can be seen that determining whether the vehicle's steering wheel is near the neutral position, or whether the absolute value change trend of the steering wheel angle is opposite to the change trend of the vehicle speed, can be used to determine the update change of the variable angle transmission ratio and the driver's steering intention. Figure 1 Therefore, in the implementation method of step S503 above, determining whether the driving state information of the vehicle satisfies the transmission ratio update condition may include determining that the steering wheel angle is within a specific angle range; the specific angle range refers to the angle range formed by the steering wheel of the vehicle being in the neutral position being less than a threshold value, indicating that the steering wheel is near the neutral position; of course, it may also include: based on multiple consecutive steering wheel angles and multiple vehicle speeds, determining that the absolute value change trend of the steering wheel angle is opposite to the vehicle speed change trend, but it is not limited to the method described in this embodiment to ensure that the update change of the variable angle transmission ratio is consistent with the driver's steering intention Figure 1 The most accurate implementation method.

[0133] To sum up, in the embodiments of the present application, according to the transmission ratio design concept newly proposed in the present application, that is, a fixed transmission ratio is adopted at low speed, a yaw angular velocity gain design is adopted at medium and low speeds, and a lateral acceleration gain design is adopted at high speed, combined with the above-mentioned linear update strategy, the vehicle's variable angle transmission ratio linear update is selectively controlled to ensure that the vehicle's variable angle transmission ratio is not too large when traveling within each speed range, and the driver's true steering intention is reliably transmitted. In addition, during high-speed driving, the variable angle transmission ratio is avoided from being reduced to affect the transmission ratio performance, thereby improving the steering stability and safety of the vehicle and the comfort of the passengers.

[0134] A variable angle transmission ratio control method provided in an embodiment of the present application is introduced above, and a device for executing the variable angle transmission ratio control method will be introduced below.

[0135] Reference Figure 7 , is a schematic diagram of the structure of a variable angle transmission ratio control device provided in an embodiment of the present application. Figure 7 As shown, the variable angle transmission ratio control device may include:

[0136] The acquisition module 710 is used to acquire the driving state information of the vehicle; the driving state information includes the steering wheel angle and the vehicle speed;

[0137] A determination module 720 is used to determine a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data represents a change relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the change relationship corresponding to different vehicle speed ranges is different;

[0138] The control module 730 is used to control the current variable angle transmission ratio of the vehicle to be updated to the target variable angle transmission ratio to achieve the vehicle steering if the driving state information satisfies the transmission ratio update condition; the transmission ratio update condition indicates whether the update change of the variable angle transmission ratio of the vehicle is consistent with the steering intention of the driver. Figure 1 To.

[0139] In a possible implementation, a generation module for generating transmission ratio data corresponding to different vehicle speed ranges in the variable angle transmission ratio control device may include:

[0140] a first acquisition unit, configured to acquire a stability constant, a yaw rate gain, and a lateral acceleration gain of the vehicle;

[0141] a first determining unit, configured to determine first transmission ratio data corresponding to a first vehicle speed range based on the stability constant and the lateral acceleration gain;

[0142] a second determining unit, configured to determine second transmission ratio data corresponding to a second vehicle speed range based on the stability constant and the yaw rate gain; the second vehicle speed range being smaller than the first vehicle speed range;

[0143] a third determining unit, configured to obtain a minimum value of the variable angle transmission ratio of the vehicle based on the stability constant and the yaw rate gain, and determine the minimum value as third transmission ratio data corresponding to a third vehicle speed range; the third vehicle speed range is smaller than the second vehicle speed range;

[0144] The first generating unit is used to generate the transmission ratio data corresponding to different continuous vehicle speed ranges by using the third transmission ratio data, the second transmission ratio data and the first transmission ratio data.

[0145] Preferably, the first acquisition unit may include:

[0146] a candidate gain value acquisition unit, configured to acquire a plurality of first candidate gain values ​​of the yaw angular velocity of the vehicle and a plurality of second candidate gain values ​​of the lateral acceleration;

[0147] a maneuverability evaluation index determination unit, configured to control the vehicle to travel at different vehicle speeds and determine maneuverability evaluation indexes corresponding to each of the first candidate gain values ​​and each of the second candidate gain values;

[0148] A selection unit is configured to select the first candidate gain value and the second candidate gain value that meet an optimization target based on the maneuverability evaluation index, and the first candidate gain value and the second candidate gain value correspond to the yaw rate gain and the lateral acceleration gain of the vehicle.

[0149] Preferably, the first generating unit may include:

[0150] an initial variable angle transmission ratio curve generating unit, configured to generate an initial variable angle transmission ratio curve of the vehicle by using the third transmission ratio data, the second transmission ratio data and the first transmission ratio data sequentially corresponding to each vehicle speed range; the initial variable angle transmission ratio curve represents a variation relationship between different vehicle speeds and different variable angle transmission ratios of the vehicle;

[0151] A smooth fitting processing unit is used to perform smooth fitting processing on the initial variable angle transmission ratio curve, and determine the variable angle transmission ratio curve after smooth fitting processing as the transmission ratio data corresponding to continuous different vehicle speed ranges, so that the determination module 720 is specifically used to determine the target variable angle transmission ratio corresponding to the current vehicle speed by querying the variable angle transmission ratio curve.

[0152] In another possible implementation, the determination module 720 may include:

[0153] A transmission ratio data determining unit, used to determine the transmission ratio data corresponding to the vehicle speed range to which the currently acquired vehicle speed belongs;

[0154] a first obtaining unit, configured to, if the vehicle speed belongs to a first vehicle speed range, substitute the lateral acceleration gain of the vehicle and the vehicle speed into a first transmission ratio expression included in the transmission ratio data to obtain a target variable angle transmission ratio corresponding to the vehicle speed;

[0155] a second obtaining unit, configured to, if the vehicle speed belongs to a second vehicle speed range, substitute the yaw rate gain of the vehicle and the vehicle speed into a second transmission ratio expression included in the transmission ratio data to obtain a target variable angle transmission ratio corresponding to the vehicle speed;

[0156] a third obtaining unit, configured to determine, if the vehicle speed belongs to a third vehicle speed range, a minimum variable angle transmission ratio of the vehicle included in the transmission ratio data as a target variable angle transmission ratio corresponding to the vehicle speed;

[0157] The second vehicle speed range is smaller than the first vehicle speed range and larger than the third vehicle speed range.

[0158] Preferably, the control module 730 may include:

[0159] A linear updating unit is used to control the current variable angle transmission ratio of the vehicle to be gradually updated to the target variable angle transmission ratio at a fixed updating rate.

[0160] Preferably, the determining unit in the control module 730 for determining whether the driving state information satisfies the transmission ratio update condition may include any of the following determining units:

[0161] A fourth determining unit is used to determine that the steering wheel angle is within a specific angle range; the specific angle range refers to an angle range in which the angle formed by the steering wheel of the vehicle being in a neutral position is less than a threshold value;

[0162] The fifth determining unit is used to determine, based on a plurality of consecutive steering wheel angles and a plurality of vehicle speeds, that a change trend of the absolute value of the steering wheel angle is opposite to a change trend of the vehicle speed.

[0163] In combination with the variable angle transmission ratio control device described in the above embodiments, the control module 730 may further include:

[0164] A maintaining unit is used to maintain the current variable angle transmission ratio of the vehicle unchanged if the driving state information does not meet the transmission ratio update condition.

[0165] Also provided in an embodiment of the present application is a computer program product including computer-readable instructions. When the computer-readable instructions are executed on a vehicle controller, the vehicle controller implements any variable angle transmission ratio control method provided in an embodiment of the present application.

[0166] 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 variable angle transmission ratio control method provided in the embodiment of the present application.

[0167] The computer-readable storage medium may be any available medium that can be stored by a computer or a data storage device such as a training device or a data center that includes one or more available media. 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 disk (SSD)).

[0168] Reference Figure 8 , is a schematic structural diagram of an optional embodiment of a vehicle controller applicable to the variable angle transmission ratio control method proposed in this application, wherein the vehicle controller is configured in a vehicle, such as Figure 8 As shown, the vehicle controller may include at least one memory 810 and at least one processor 820, and the at least one memory 810 and the at least one processor 820 may communicate with each other via a bus 830. The bus 830 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 8 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0169] The memory 810 is used to store multiple computer instructions, which are loaded and executed by the processor 820 to implement the various steps of the variable angle transmission ratio control method proposed in the embodiment of the present application. Other components in the vehicle (such as sensors or steering mechanisms, etc.) can also be called to implement corresponding functions. The implementation process can refer to the description of the corresponding part of the method embodiment above.

[0170] In the embodiment of the present application, the memory 810 includes a volatile memory (volatile memory), such as a random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as a read-only memory (ROM), a flash memory, a hard drive drive (HDD) or a solid state drive (SSD), etc. The processor 820 may include any one or more of a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), a digital signal processor (DSP), an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). The present application does not limit the types of the memory 810 and the processor 820 and their working principles, and can be flexibly configured according to actual needs.

[0171] In practical applications, the memory 8100 can be used to store computer instructions and data, and may include an instruction storage area and a data storage area. The data storage area may store various data, such as various driving status information detected by sensors, such as vehicle speed, steering wheel angle, etc., and intermediate data generated during the variable angle transmission ratio control process, etc.; the instruction storage area may store software units such as operating systems, applications, and computer instructions required for at least one function, etc. As analyzed above, the memory 810 may provide the processor 820 with multiple computer instructions for implementing the variable angle transmission ratio control method of the embodiment of the present application, as well as data or other software and hardware resources required during the execution of the variable angle transmission ratio control method, etc.

[0172] It should be understood that Figure 8 The structure of the vehicle controller shown does not constitute a limitation on the vehicle controller in the embodiment of the present application. In practical applications, the vehicle controller may include Figure 8 More components shown, or combinations of certain components, etc., are not listed one by one in this application.

[0173] The embodiment of the present application also provides a vehicle, which may include a vehicle controller as described in the above embodiment. The vehicle may be any type of vehicle, such as a personal car, a bus, a truck, or a new energy vehicle (such as a hybrid vehicle or a pure electric vehicle). The vehicle may use the vehicle controller configured therein to execute the variable angle transmission ratio control method proposed in the embodiment of the present application. Through the newly designed transmission ratio data and its update strategy, in the process of realizing the wire-controlled steering control, the stability and safety of the vehicle steering can be reliably guaranteed, the potential risk of vehicle instability can be avoided, and the driving experience can be improved.

[0174] In addition, it should be noted that the device 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 device 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.

[0175] 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.

[0176] 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. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated.

[0177] In addition, the various embodiments in this specification are described in a progressive or parallel manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. For the device and vehicle controller disclosed in the embodiment, since they correspond to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0178] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A variable angle transmission ratio control method, characterized in that: The variable angle transmission ratio control method comprises: Acquiring driving state information of the vehicle; the driving state information includes a steering wheel angle and a vehicle speed; Determine a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data represents a change relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the change relationship corresponding to different vehicle speed ranges is different; If the driving status information satisfies the transmission ratio update condition, the current variable angle transmission ratio of the vehicle is controlled to be updated to the target variable angle transmission ratio to achieve the vehicle steering; the transmission ratio update condition indicates that the updated change of the variable angle transmission ratio of the vehicle is consistent with the driver's steering intention.

2. The variable angle transmission ratio control method according to claim 1, characterized in that: The process of generating the transmission ratio data corresponding to different vehicle speed ranges includes: Obtaining a stability constant, a yaw rate gain, and a lateral acceleration gain of the vehicle; Determining first transmission ratio data corresponding to a first vehicle speed range based on the stability constant and the lateral acceleration gain; determining second transmission ratio data corresponding to a second vehicle speed range based on the stability constant and the yaw rate gain; the second vehicle speed range is smaller than the first vehicle speed range; Based on the stability constant and the yaw rate gain, a minimum value of the variable angle transmission ratio of the vehicle is obtained and determined as third transmission ratio data corresponding to a third vehicle speed range; the third vehicle speed range is smaller than the second vehicle speed range; The third transmission ratio data, the second transmission ratio data and the first transmission ratio data are used to generate transmission ratio data corresponding to continuously different vehicle speed ranges.

3. The variable angle transmission ratio control method according to claim 2, characterized in that: The obtaining of the yaw rate gain and the lateral acceleration gain of the vehicle comprises: Acquire a plurality of first candidate gain values ​​of the yaw rate of the vehicle and a plurality of second candidate gain values ​​of the lateral acceleration; Controlling the vehicle to travel at different vehicle speeds, and determining maneuverability evaluation indices corresponding to each of the first candidate gain values ​​and each of the second candidate gain values; Based on the maneuverability evaluation index, the first candidate gain value and the second candidate gain value that meet the optimization target are selected to correspond to the yaw rate gain and the lateral acceleration gain of the vehicle.

4. The variable angle transmission ratio control method according to claim 2, characterized in that: The step of using the third transmission ratio data, the second transmission ratio data and the first transmission ratio data to generate transmission ratio data corresponding to continuously different vehicle speed ranges includes: Generate an initial variable angle transmission ratio curve of the vehicle by using the third transmission ratio data, the second transmission ratio data and the first transmission ratio data corresponding to each vehicle speed range in sequence; the initial variable angle transmission ratio curve represents the changing relationship between different vehicle speeds and different variable angle transmission ratios of the vehicle; The initial variable angle transmission ratio curve is subjected to smooth fitting processing, and the variable angle transmission ratio curve after smooth fitting processing is determined as transmission ratio data corresponding to continuous different vehicle speed ranges, so as to determine the target variable angle transmission ratio corresponding to the vehicle speed by querying the variable angle transmission ratio curve.

5. The variable angle transmission ratio control method according to claim 1, characterized in that: The step of determining a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges includes: Determine the transmission ratio data corresponding to the vehicle speed range to which the currently acquired vehicle speed belongs; If the vehicle speed belongs to the first vehicle speed range, substituting the lateral acceleration gain of the vehicle and the vehicle speed into the first transmission ratio expression included in the transmission ratio data to obtain a target variable angle transmission ratio corresponding to the vehicle speed; If the vehicle speed belongs to the second vehicle speed range, substituting the yaw rate gain of the vehicle and the vehicle speed into the second transmission ratio expression included in the transmission ratio data to obtain a target variable angle transmission ratio corresponding to the vehicle speed; If the vehicle speed belongs to a third vehicle speed range, determining the minimum variable angle transmission ratio of the vehicle contained in the transmission ratio data as a target variable angle transmission ratio corresponding to the vehicle speed; The second vehicle speed range is smaller than the first vehicle speed range and larger than the third vehicle speed range.

6. The variable angle transmission ratio control method according to any one of claims 1 to 5, characterized in that: The controlling the current variable angle transmission ratio of the vehicle to update to the target variable angle transmission ratio comprises: According to a fixed update rate, the current variable angle transmission ratio of the vehicle is controlled to be gradually updated to the target variable angle transmission ratio.

7. The variable angle transmission ratio control method according to any one of claims 1 to 5, characterized in that: The driving state information satisfies the transmission ratio update condition, including any of the following implementation methods: Determining that the steering wheel angle is within a specific angle range; the specific angle range refers to an angle range in the form of an angle less than a threshold value from the steering wheel of the vehicle being in a neutral position; Based on a plurality of consecutive steering wheel angles and a plurality of vehicle speeds, it is determined that a change trend of the absolute value of the steering wheel angle is opposite to a change trend of the vehicle speed.

8. The variable angle transmission ratio control method according to any one of claims 1 to 5, characterized in that: The variable angle transmission ratio control method further includes: If the driving state information does not satisfy the transmission ratio update condition, the current variable angle transmission ratio of the vehicle is maintained unchanged.

9. A variable angle transmission ratio control device, characterized in that: The variable angle transmission ratio control device comprises: An acquisition module, used to acquire driving state information of the vehicle; the driving state information includes a steering wheel angle and a vehicle speed; a determination module, configured to determine a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data representing a change relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the change relationship corresponding to different vehicle speed ranges is different; A control module is used to control the current variable angle transmission ratio of the vehicle to be updated to the target variable angle transmission ratio to achieve the vehicle steering if the driving state information satisfies the transmission ratio update condition; the transmission ratio update condition indicates that the updated change of the variable angle transmission ratio of the vehicle is consistent with the driver's steering intention.

10. A vehicle controller, the vehicle controller being arranged in a vehicle, characterized in that: The vehicle controller includes: at least one memory and at least one processor, The memory is used to store a plurality of computer instructions; The processor is used to execute the multiple computer instructions to implement the following steps: Acquiring driving state information of the vehicle; the driving state information includes a steering wheel angle and a vehicle speed; Determine a target variable angle transmission ratio corresponding to the vehicle speed based on the generated transmission ratio data corresponding to different vehicle speed ranges; the transmission ratio data represents a change relationship between the vehicle speed and the variable angle transmission ratio within the corresponding vehicle speed range, and the change relationship corresponding to different vehicle speed ranges is different; If the driving status information satisfies the transmission ratio update condition, the current variable angle transmission ratio of the vehicle is controlled to be updated to the target variable angle transmission ratio to achieve the vehicle steering; the transmission ratio update condition indicates that the updated change of the variable angle transmission ratio of the vehicle is consistent with the driver's steering intention.

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