Lateral control method for vehicle driving, and processor and vehicle

Abstract

The present application belongs to the technical field of lateral control. Disclosed are a lateral control method for vehicle driving, and a processor and a vehicle. The lateral control method comprises: acquiring a rotation angle of a steering electric motor within a first preset time period; determining a front-wheel steering angle of a steering front wheel within the first preset time period and a target front-wheel steering angle; on the basis of the rotation angle, the front-wheel steering angle, and a preset steering ratio of a steering wheel to the steering front wheel, determining a neutral-position rotation angle of the steering electric motor of when the steering wheel is in a neutral position; on the basis of the target front-wheel steering angle, the neutral-position rotation angle and the preset steering ratio, determining a target rotation angle of the steering electric motor; and according to the target rotation angle, controlling the steering electric motor to operate, so as to complete lateral control for vehicle driving. The present application can improve the stability of lateral control for vehicle driving.

Description

Lateral control methods, processors, and vehicles for vehicle driving

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202410984354.8, filed on July 22, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of lateral control technology, and more specifically to a lateral control method, processor, and vehicle for vehicle driving. Background Technology

[0004] Most vehicle steering systems use hydraulic steering systems. Due to the possibility of hydraulic oil leakage, the correspondence between the steering wheel position and the front wheel position changes over time. In other words, the center position of the steering wheel, where the front wheel steering angle is 0, changes over time. Therefore, during lateral control for straight-line trajectory tracking, it is impossible to control the vehicle to travel in a straight line by pre-setting the center position. Thus, during lateral control, it is necessary to determine the steering wheel's center position in real time to ensure the vehicle travels in a straight line. However, existing lateral control methods are often affected by data acquisition accuracy or the operating environment, resulting in poor stability in lateral control. Summary of the Invention

[0005] The purpose of this application is to provide a lateral control method, processor, and vehicle for vehicle driving, in order to solve the problem of poor stability in existing lateral control methods.

[0006] To achieve the above objectives, a first aspect of this application provides a lateral control method for vehicle driving, wherein the vehicle includes a steering wheel, a front steering wheel, and a steering motor corresponding to the steering wheel, and the lateral control method includes:

[0007] Obtain the rotation angle of the steering motor within the first preset time period;

[0008] Determine the front wheel steering angle and target front wheel steering angle within the first preset time period;

[0009] Based on the rotation angle, the front wheel steering angle, and the preset steering ratio between the steering wheel and the front steering wheel, the center rotation angle of the steering motor is determined when the steering wheel is in the center position.

[0010] The target rotation angle of the steering motor is determined based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio.

[0011] The steering motor is controlled to operate according to the target rotation angle in order to complete the lateral control of the vehicle driving.

[0012] In this embodiment of the application, the neutral rotation angle of the steering motor when the steering wheel is in the neutral position is determined based on the rotation angle, the front wheel steering angle, and the preset steering ratio between the steering wheel and the steering front wheel. This includes: determining the steering angle of the steering wheel based on the product of the front wheel steering angle and the preset steering ratio; and subtracting the steering angle of the steering wheel from the rotation angle to obtain the neutral rotation angle.

[0013] In this embodiment of the application, determining the front wheel steering angle of the steering wheel includes: acquiring the vehicle's wheelbase and linear velocity, as well as the vehicle's first heading angle in the previous sampling period and the second heading angle in the current sampling period; determining the heading angle difference based on the second heading angle and the first heading angle; determining the vehicle's rear axle center turning radius based on the linear velocity and the heading angle difference, according to a pre-determined vehicle kinematic model; and determining the front wheel steering angle based on the rear axle center turning radius and the wheelbase.

[0014] In this embodiment of the application, the lateral control method further includes: determining a maximum heading angle difference based on a preset maximum front wheel steering angle; determining whether the heading angle difference is greater than the maximum heading angle difference; and updating a second heading angle based on a first heading angle and the front wheel steering angle of the previous sampling period if the heading angle difference is greater than the maximum heading angle difference.

[0015] In this embodiment, determining the target front wheel steering angle includes: acquiring the vehicle's position, speed, heading angle, actual trajectory, and target trajectory; determining the initial front wheel steering angle based on the position, speed, heading angle, and target trajectory using a pure tracking control algorithm; determining the front wheel steering angle compensation amount based on the lateral error between the actual trajectory and the target trajectory using proportional-integral-derivative control; and adding the initial front wheel steering angle to the front wheel steering angle compensation amount to obtain the target front wheel steering angle.

[0016] In this embodiment of the application, the lateral control method further includes: re-determining the center rotation angle based on the rotation angle, the front wheel steering angle and the preset steering ratio every preset time interval within a second preset time period to obtain multiple center rotation angles; filtering the multiple center rotation angles to determine multiple filtered center rotation angles; determining the average value of the multiple filtered center rotation angles and determining the average value as the processed center rotation angle.

[0017] In this embodiment of the application, the lateral control method further includes: acquiring the historical rotation angle of the steering motor within a target time period, wherein the target time period is from the previous sampling period to the current sampling period; determining the corresponding front wheel steering angle change value based on the historical rotation angle; adding the front wheel steering angle of the previous sampling period and the front wheel steering angle change value to determine the predicted front wheel steering angle value; and correcting the predicted front wheel steering angle value based on the front wheel steering angle using a Kalman filter algorithm to obtain the corrected front wheel steering angle.

[0018] In this embodiment of the application, determining the target rotation angle of the steering motor based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio includes: determining the initial rotation angle of the steering motor based on the product of the target front wheel steering angle and the preset steering ratio; and adding the initial rotation angle to the center rotation angle to obtain the target rotation angle.

[0019] A second aspect of this application provides a processor configured to execute the above-described lateral control method for vehicle driving.

[0020] A third aspect of this application provides a vehicle, including: a steering wheel; a steering front wheel; a steering motor corresponding to the steering wheel; and a processor.

[0021] The aforementioned technical solution obtains the rotation angle of the steering motor within a first preset time period, and simultaneously determines the front wheel steering angle and target front wheel steering angle within the first preset time period. Then, based on the rotation angle, front wheel steering angle, and a preset steering ratio between the steering wheel and the front wheels, it determines the center rotation angle of the steering motor when the steering wheel is in the center position. Subsequently, based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio, it determines the target rotation angle of the steering motor, and finally controls the steering motor to operate according to the target rotation angle to achieve lateral control of the vehicle. This application, by determining the center rotation angle of the steering motor when the steering wheel is in the center position based on the rotation angle, front wheel steering angle, and preset steering ratio between the steering wheel and the front wheels, and then determining the target rotation angle of the steering motor based on the center rotation angle, and controlling the steering motor to operate according to the target rotation angle, can reduce the impact of front wheel steering angle data errors on vehicle lateral control and improve the stability of lateral control.

[0022] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0024] Figure 1 schematically illustrates a flow diagram of a lateral control method for vehicle driving according to an embodiment of this application;

[0025] Figure 2 schematically illustrates a vehicle kinematics model according to an embodiment of this application;

[0026] Figure 3 schematically illustrates a simplified model of a vehicle steering system according to an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0029] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0030] Figure 1 schematically illustrates a flowchart of a lateral control method for vehicle driving according to an embodiment of this application. As shown in Figure 1, this embodiment of the application provides a lateral control method for vehicle driving. The vehicle includes a steering wheel, front steering wheels, and a steering motor corresponding to the steering wheel. Taking the application of this lateral control method to a processor as an example, the lateral control method may include the following steps:

[0031] Step S101: Obtain the rotation angle of the steering motor within the first preset time period.

[0032] Step S102: Determine the front wheel steering angle and target front wheel steering angle of the steering front wheel within the first preset time period.

[0033] Step S103: Determine the center rotation angle of the steering motor when the steering wheel is in the center position based on the rotation angle, the front wheel steering angle, and the preset steering ratio between the steering wheel and the front steering wheel.

[0034] Step S104: Determine the target rotation angle of the steering motor based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio.

[0035] Step S105: Control the steering motor to work according to the target rotation angle to complete the lateral control of vehicle driving.

[0036] The lateral control method for vehicle driving provided in this application embodiment can be used in vehicles equipped with an Ackerman chassis, such as excavators, loaders, or agricultural machinery equipped with an Ackerman chassis. The vehicle includes a steering wheel, front steering wheels, and a steering motor corresponding to the steering wheel. The rotation angle of the steering motor refers to the angle of rotation on the motor shaft. The front wheel steering angle refers to the angle between the front steering wheels and the vehicle's long axis. The target front wheel steering angle refers to the angle between the front steering wheels and the vehicle's long axis to which the steering wheels are to be controlled. The steering motor is mounted on the steering column. When the steering wheel is turned, steering force is transmitted to the steering motor through the steering column, allowing the steering motor to directly respond to the steering wheel's rotation command, thereby driving the front wheels to change direction.

[0037] While the center position of a vehicle's hydraulic steering system changes over time, extensive practical experience shows that when the steering wheel angle is small, the change in steering wheel center position is also relatively small and slow. However, in scenarios with high curvature driving, the change in steering wheel center position is more noticeable and rapid. In current mainstream straight-line tracking scenarios, a stable center position can be considered to exist within a short period of time. Therefore, this application proposes a method for determining a stable center position in straight-line tracking scenarios and performing lateral control of the vehicle's autonomous driving based on the calculated stable center position.

[0038] In this embodiment, the processor can obtain the rotation angle of the steering motor within a first preset time period through the position encoder of the steering motor, and simultaneously determine the front wheel steering angle of the steering front wheels within the first preset time period and the target front wheel steering angle at the current time point. The first preset time period is the time period from a historical time point to the current time point, and the duration can be adjusted according to actual needs. Since the correspondence between the steering wheel steering angle and the steering motor rotation angle changes over time, the processor can obtain the preset steering ratio between the steering wheel and the steering front wheels, and determine the center rotation angle of the steering motor in real time when the steering wheel is in the center position based on the rotation angle, the front wheel steering angle, and the preset steering ratio between the steering wheel and the steering front wheels. The preset steering ratio can be determined in advance after calibration based on the characteristics of the vehicle steering system. After determining the center rotation angle of the steering motor at the current time point, the processor can determine the target rotation angle of the steering motor based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio, and send the corresponding speed command to the steering motor according to the target rotation angle to control the steering motor to rotate to the target rotation angle, thereby enabling the vehicle to move according to the target trajectory and achieving lateral control of vehicle driving.

[0039] The aforementioned technical solution obtains the rotation angle of the steering motor within a first preset time period, and simultaneously determines the front wheel steering angle and target front wheel steering angle within the first preset time period. Then, based on the rotation angle, front wheel steering angle, and a preset steering ratio between the steering wheel and the front wheels, it determines the center rotation angle of the steering motor when the steering wheel is in the center position. Subsequently, based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio, it determines the target rotation angle of the steering motor, and finally controls the steering motor to operate according to the target rotation angle to achieve lateral control of the vehicle. This application, by determining the center rotation angle of the steering motor when the steering wheel is in the center position based on the rotation angle, front wheel steering angle, and preset steering ratio between the steering wheel and the front wheels, and then determining the target rotation angle of the steering motor based on the center rotation angle, and controlling the steering motor to operate according to the target rotation angle, can reduce the impact of front wheel steering angle data errors on vehicle lateral control and improve the stability of lateral control.

[0040] Figure 2 schematically illustrates a vehicle kinematics model according to an embodiment of this application. As shown in Figure 2, in this embodiment, determining the front wheel steering angle of the steering front wheel includes: obtaining the vehicle's wheelbase and linear velocity, as well as the vehicle's first heading angle in the previous sampling period and a second heading angle in the current sampling period; determining the heading angle difference based on the second heading angle and the first heading angle; determining the vehicle's rear axle center turning radius based on the linear velocity and the heading angle difference, according to a pre-determined vehicle kinematics model; and determining the front wheel steering angle based on the rear axle center turning radius and the wheelbase.

[0041] Specifically, the vehicle is equipped with a navigation receiver. The navigation receiver is a device that uses the Global Navigation Satellite System (GNSS) positioning and inertial measurement unit fusion to obtain the current position and attitude data. The processor can acquire the data sent by the navigation receiver. The data sent by the navigation receiver is discrete data with a fixed sampling period, including the vehicle's heading angle, speed, etc. The sampling period can be adjusted according to the actual situation. Therefore, through the navigation receiver, the processor can acquire the vehicle's linear velocity v, as well as the vehicle's first heading angle heading1 in the previous sampling period and the second heading angle heading2 in the current sampling period, and then determine the heading angle difference θ between the second heading angle heading2 and the first heading angle heading1. Then, based on the vehicle's kinematic model, the processor can determine the vehicle's rear axle center turning radius according to the linear velocity and the heading angle difference. The rear axle center turning radius satisfies formula (1):

[0042] Where v is the linear velocity, dt is the sampling period, R is the turning radius of the rear axle center, and θ is the heading angle difference.

[0043] Furthermore, the processor can obtain the vehicle's wheelbase (wheelbase). Subsequently, the processor can further determine the front wheel steering angle δ based on the rear axle center turning radius R and the wheelbase (wheelbase). The front wheel steering angle δ satisfies formula (2):

[0044] Where R is the turning radius of the rear axle center, wheelbase is the wheelbase, and δ is the front wheel steering angle.

[0045] In this way, the processor can determine the front wheel steering angle, which makes it easier to determine the center rotation angle of the steering motor by combining the rotation angle, the front wheel steering angle and the preset steering ratio.

[0046] In this embodiment of the application, the lateral control method further includes: determining a maximum heading angle difference based on a preset maximum front wheel steering angle; determining whether the heading angle difference is greater than the maximum heading angle difference; and updating a second heading angle based on a first heading angle and the front wheel steering angle of the previous sampling period if the heading angle difference is greater than the maximum heading angle difference.

[0047] The processor can correct the second heading angle acquired in the current sampling period. Specifically, the processor can acquire a preset maximum front wheel steering angle. The preset maximum front wheel steering angle can be less than or equal to 35 degrees and can be adjusted according to the actual situation. Then, based on the preset maximum front wheel steering angle, the processor can determine the corresponding maximum rear axle center turning radius according to the aforementioned formula (2), and then determine the maximum heading angle difference according to the aforementioned formula (1) and the maximum rear axle center turning radius. Further, the processor can determine whether the heading angle difference θ between the second heading angle heading2 and the first heading angle heading1 is greater than the maximum heading angle difference. If the heading angle difference θ is greater than the maximum heading angle difference, the processor can determine that the second heading angle heading2 is abnormal and needs to be corrected. Since the front wheel steering angle of the previous sampling period will cause the heading angle of the current sampling period to change, the processor can update the second heading angle according to the first heading angle heading1 and the front wheel steering angle determined in the previous sampling period. Specifically, the processor can add the first heading angle (heading1) to the change in heading angle caused by the front wheel steering angle in the previous sampling period, and use this as the updated second heading angle to update the second heading angle (heading2) for the current sampling period. In this way, by correcting the second heading angle (heading2) for the current sampling period, the accuracy of the front wheel steering angle determined based on the second heading angle (heading2) can be improved.

[0048] In this embodiment of the application, the lateral control method further includes: acquiring the historical rotation angle of the steering motor within a target time period, wherein the target time period is from the previous sampling period to the current sampling period; determining the corresponding front wheel steering angle change value based on the historical rotation angle; adding the front wheel steering angle of the previous sampling period and the front wheel steering angle change value to determine the predicted front wheel steering angle value; and correcting the predicted front wheel steering angle value based on the front wheel steering angle using a Kalman filter algorithm to obtain the corrected front wheel steering angle.

[0049] The vehicle's heading angle is significantly affected by the driving environment, and navigation receivers have inherent errors. Therefore, the front wheel steering angle determined based on the acquired heading angle will be inaccurate. To improve the accuracy of the front wheel steering angle, the processor can correct it. Specifically, the processor can acquire the historical rotation angle of the steering motor within a target time period from the previous sampling period to the current sampling period. It can be understood that there is a corresponding functional relationship between the steering wheel angle and the change in the front wheel steering angle, which can be approximated using a linear model with a follower dead zone. The change in the steering motor's rotation angle corresponds to the steering wheel angle, and this change will lead to a change in the front wheel steering angle. Therefore, based on the functional relationship between the steering wheel angle and the change in the front wheel steering angle, the processor can determine the corresponding change value of the front wheel steering angle based on the historical rotation angles. By adding the front wheel steering angle from the previous sampling period and the change value of the front wheel steering angle, the predicted value of the front wheel steering angle can be determined. Thus, after obtaining the predicted front wheel steering angle and the front wheel steering angle, the processor can correct the predicted front wheel steering angle based on the front wheel steering angle using the Kalman filter algorithm. After the front wheel steering angle and the predicted front wheel steering angle are fused, the corrected front wheel steering angle is obtained, thereby completing the correction process of the front wheel steering angle of the steering wheel.

[0050] In this embodiment, determining the target front wheel steering angle includes: acquiring the vehicle's position, speed, heading angle, actual trajectory, and target trajectory; determining the initial front wheel steering angle based on the position, speed, heading angle, and target trajectory using a pure tracking control algorithm; determining the front wheel steering angle compensation amount based on the lateral error between the actual trajectory and the target trajectory using proportional-integral-derivative control; and adding the initial front wheel steering angle to the front wheel steering angle compensation amount to obtain the target front wheel steering angle.

[0051] Specifically, through the navigation receiver, the processor can acquire the vehicle's position, speed, heading angle, actual trajectory, and target trajectory. Thus, using a pure tracking control algorithm, the processor can determine the initial front wheel steering angle based on the position, speed, heading angle, and target trajectory. This process can be implemented with reference to existing technologies and will not be elaborated here. Furthermore, after determining the lateral error between the vehicle's actual trajectory and the target trajectory, the processor can employ proportional-integral-derivative (PID) control to determine the front wheel steering angle compensation based on the lateral error. It should be noted that when determining the front wheel steering angle compensation, only integral control from PID control can be used. After adding the initial front wheel steering angle to the front wheel steering angle compensation, the processor can determine the target front wheel steering angle steer_theta.

[0052] Figure 3 schematically illustrates a simplified model of a vehicle steering system according to an embodiment of this application. As shown in Figure 3, in this embodiment, determining the center rotation angle of the steering motor when the steering wheel is in the center position, based on the rotation angle, the front wheel steering angle, and the preset steering ratio between the steering wheel and the front wheels, includes: determining the steering angle of the steering wheel based on the product of the front wheel steering angle and the preset steering ratio; and subtracting the steering angle of the steering wheel from the rotation angle to obtain the center rotation angle.

[0053] Since the relationship between the steering wheel's steering angle and the steering motor's rotation angle changes over time, the processor can determine the steering motor's center rotation angle A in real time when the steering wheel is in the center position, based on the rotation angle B, the front wheel steering angle δ, and the preset steering ratio steer_ratio. Specifically, the preset steering ratio steer_ratio is the steering ratio between the steering wheel and the front wheels. Therefore, based on the product of the front wheel steering angle δ and the preset steering ratio steer_ratio, the processor can determine the steering wheel's steering angle α, i.e., the angle between the steering wheel and the center position. Furthermore, it can be understood that the steering motor, mounted on the steering column, directly responds to the steering wheel's steering angle; in this case, the steering motor's rotation angle can be considered equal to the steering wheel's steering angle. Therefore, the processor can subtract the steering wheel's steering angle α from the steering motor's rotation angle B to obtain the steering motor's center rotation angle A.

[0054] In this embodiment of the application, the lateral control method further includes: re-determining the center rotation angle based on the rotation angle, the front wheel steering angle and the preset steering ratio every preset time interval within a second preset time period to obtain multiple center rotation angles; filtering the multiple center rotation angles to determine multiple filtered center rotation angles; determining the average value of the multiple filtered center rotation angles and determining the average value as the processed center rotation angle.

[0055] Because single data points may contain errors, and considering the nonlinearity of the steering system, dead zones, and steering clearance issues, the processor can process the center rotation angle based on the principle that the center position remains constant within a short preset time period. Specifically, within a second preset time period, the processor can re-determine the center rotation angle according to the aforementioned method, based on the rotation angle, front wheel steering angle, and preset steering ratio, at preset intervals to obtain multiple center rotation angles. The second preset time period is a short period that can be adjusted according to actual needs, for example, it can be set to 10 seconds. The preset duration can also be set and adjusted according to actual needs. Then, the processor can filter the multiple center rotation angles to obtain multiple filtered center rotation angles. In one example, outliers among the multiple center rotation angles can be removed based on the 3sigma principle, resulting in multiple outlier-removed center rotation angles, which are then further sorted. After sorting, the processor can discard the median rotation angles from the first preset proportion and the second preset proportion, thus obtaining multiple filtered median rotation angles. Both the first and second preset proportions can be set according to the accuracy requirements of the data processing. The first and second preset proportions can be equal or unequal. Finally, the processor can determine the average value of the multiple filtered median rotation angles and set this average value as the processed median rotation angle. This improves the accuracy of the determined median rotation angle.

[0056] In this embodiment of the application, determining the target rotation angle of the steering motor based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio includes: determining the initial rotation angle of the steering motor based on the product of the target front wheel steering angle and the preset steering ratio; and adding the initial rotation angle to the center rotation angle to obtain the target rotation angle.

[0057] The processor can determine the target rotation angle of the steering motor based on the target front wheel steering angle *steer_theta*, the center rotation angle *A*, and the preset steering ratio *steer_ratio*. Specifically, multiplying the target front wheel steering angle *steer_theta* and the preset steering ratio *steer_ratio* determines the target steering angle of the steering wheel. Since the steering motor is mounted on the steering column and directly responds to the steering wheel's rotation angle, its rotation angle can be considered equal to the steering wheel's rotation angle. Therefore, the target steering angle of the steering wheel can be considered equal to the initial rotation angle of the steering motor. In other words, the initial rotation angle of the steering motor can be determined. Thus, by adding the initial rotation angle to the center rotation angle, the processor can determine the current target rotation angle of the steering motor.

[0058] It should be noted that if the vehicle is equipped with a high-precision front wheel steering angle detection device, the processor can also perform feedback control based on the front wheel steering angle obtained by the front wheel steering angle detection device, without having to control the steering motor to achieve steering by determining the center rotation angle and then the target rotation angle.

[0059] In summary, compared with the prior art, the technical solution provided in this application has the following advantages:

[0060] This application reduces the error in the front wheel steering angle calculation process by data filtering without obtaining the front wheel steering angle or adding additional hardware costs such as angle sensors and proportional valves. It determines the steady-state center position of the steering wheel within a short period of time based on the processed front wheel steering angle, and then determines the target rotation angle of the steering motor based on the steady-state center position. Compared with traditional lateral control methods, this can make the vehicle have better stability on road conditions with low friction and uneven grip.

[0061] This application also provides a processor configured to execute the above-described lateral control method for vehicle driving.

[0062] Specifically, in this embodiment, the processor can be configured to: acquire the rotation angle of the steering motor within a first preset time period; determine the front wheel steering angle and the target front wheel steering angle within the first preset time period; determine the center rotation angle of the steering motor when the steering wheel is in the center position based on the rotation angle, the front wheel steering angle, and the preset steering ratio between the steering wheel and the front wheel; determine the target rotation angle of the steering motor based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio; and control the steering motor to operate according to the target rotation angle to complete the lateral control of vehicle driving.

[0063] In one embodiment, the processor is further configured to: determine the steering angle of the steering wheel based on the product of the front wheel steering angle and a preset steering ratio; and subtract the steering angle of the steering wheel from the rotation angle to obtain the center rotation angle.

[0064] In one embodiment, the processor is further configured to: acquire the vehicle's wheelbase and linear velocity, as well as the vehicle's first heading angle in the previous sampling period and a second heading angle in the current sampling period; determine the heading angle difference based on the second heading angle and the first heading angle; determine the vehicle's rear axle center turning radius based on the linear velocity and the heading angle difference, according to a pre-determined vehicle kinematics model; and determine the front wheel steering angle based on the rear axle center turning radius and the wheelbase.

[0065] In one embodiment, the processor is further configured to: determine a maximum heading angle difference based on a preset maximum front wheel steering angle; determine whether the heading angle difference is greater than the maximum heading angle difference; and update a second heading angle based on a first heading angle and the front wheel steering angle of the previous sampling period if the heading angle difference is greater than the maximum heading angle difference.

[0066] In one embodiment, the processor is further configured to: acquire the vehicle's position, speed, heading angle, actual trajectory, and target trajectory; determine an initial front wheel steering angle based on the position, speed, heading angle, and target trajectory using a pure tracking control algorithm; determine a front wheel steering angle compensation amount based on the lateral error between the actual trajectory and the target trajectory using proportional-integral-derivative control; and add the initial front wheel steering angle to the front wheel steering angle compensation amount to obtain the target front wheel steering angle.

[0067] In one embodiment, the processor is further configured to: re-determine the median rotation angle based on the rotation angle, the front wheel steering angle, and the preset steering ratio every preset time interval within a second preset time period to obtain multiple median rotation angles; filter the multiple median rotation angles to determine multiple filtered median rotation angles; determine the average value of the multiple filtered median rotation angles, and determine the average value as the processed median rotation angle.

[0068] In one embodiment, the processor is further configured to: acquire the historical rotation angle of the steering motor within a target time period, the target time period being from the previous sampling period to the current sampling period; determine the corresponding front wheel steering angle change value based on the historical rotation angle; add the front wheel steering angle of the previous sampling period and the front wheel steering angle change value to determine the predicted front wheel steering angle value; and correct the predicted front wheel steering angle value based on the front wheel steering angle using a Kalman filter algorithm to obtain the corrected front wheel steering angle.

[0069] In one embodiment, the processor is further configured to: determine the initial rotation angle of the steering motor based on the product of the target front wheel steering angle and the preset steering ratio; and add the initial rotation angle to the midpoint rotation angle to obtain the target rotation angle.

[0070] The aforementioned technical solution obtains the rotation angle of the steering motor within a first preset time period, and simultaneously determines the front wheel steering angle and target front wheel steering angle within the first preset time period. Then, based on the rotation angle, front wheel steering angle, and a preset steering ratio between the steering wheel and the front wheels, it determines the center rotation angle of the steering motor when the steering wheel is in the center position. Subsequently, based on the target front wheel steering angle, the center rotation angle, and the preset steering ratio, it determines the target rotation angle of the steering motor, and finally controls the steering motor to operate according to the target rotation angle to achieve lateral control of the vehicle. This application, by determining the center rotation angle of the steering motor when the steering wheel is in the center position based on the rotation angle, front wheel steering angle, and preset steering ratio between the steering wheel and the front wheels, and then determining the target rotation angle of the steering motor based on the center rotation angle, and controlling the steering motor to operate according to the target rotation angle, can reduce the impact of front wheel steering angle data errors on vehicle lateral control and improve the stability of lateral control.

[0071] This application also provides a vehicle, including: a steering wheel; a front steering wheel; a steering motor corresponding to the steering wheel; and a processor.

[0072] This application also provides a machine-readable storage medium storing instructions for causing a machine to perform the aforementioned lateral control method for vehicle driving.

[0073] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0074] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart illustrations and / or one or more block diagrams.

[0075] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0076] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0077] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0078] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0079] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0080] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0081] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A lateral control method for vehicle driving, characterized by, The vehicle comprises a steering wheel, a front wheel and a steering motor corresponding to the steering wheel, and the lateral control method comprises: acquiring a rotation angle of the steering motor in a first preset time period; determining a front wheel steering angle of the front wheel in the first preset time period and a target front wheel steering angle; determining a neutral rotation angle of the steering motor when the steering wheel is in a neutral position according to the rotation angle, the front wheel steering angle and a preset steering ratio of the steering wheel and the front wheel; determining a target rotation angle of the steering motor according to the target front wheel steering angle, the neutral rotation angle and the preset steering ratio; controlling the steering motor to work according to the target rotation angle, so as to complete the lateral control of the vehicle driving.

2. The lateral control method according to claim 1, characterized by, The determination of the neutral rotation angle of the steering motor when the steering wheel is in the neutral position according to the rotation angle, the front wheel steering angle and the preset steering ratio of the steering wheel and the front wheel comprises: determining a steering angle of the steering wheel according to a product of the front wheel steering angle and the preset steering ratio; subtracting the steering angle of the steering wheel from the rotation angle to obtain the neutral rotation angle.

3. The lateral control method according to claim 1, characterized by, The determination of the front wheel steering angle of the front wheel comprises: acquiring a wheelbase and a linear velocity of the vehicle, and a first heading angle of the vehicle in a last sampling period and a second heading angle of the vehicle in a current sampling period; determining a heading angle difference value according to the second heading angle and the first heading angle; determining a rear axle center turning radius of the vehicle according to the linear velocity and the heading angle difference value based on a pre-determined vehicle kinematics model; determining the front wheel steering angle according to the rear axle center turning radius and the wheelbase.

4. The lateral control method according to claim 3, characterized by, The lateral control method further comprises: determining a maximum heading angle difference value based on a preset maximum front wheel steering angle; judging whether the heading angle difference value is greater than the maximum heading angle difference value; in the case that the heading angle difference value is greater than the maximum heading angle difference value, updating the second heading angle according to the first heading angle and a front wheel steering angle in a last sampling period.

5. The lateral control method of claim 1, wherein The determination of the target front wheel steering angle comprises: acquiring a position, a speed, a heading angle, an actual motion trajectory and a target motion trajectory of the vehicle; determining an initial front wheel steering angle according to the position, the speed, the heading angle and the target motion trajectory through a pure tracking control algorithm; determining a front wheel steering angle compensation amount according to a lateral error between the actual motion trajectory and the target motion trajectory through proportional integral differential control; adding the initial front wheel steering angle and the front wheel steering angle compensation amount to obtain the target front wheel steering angle.

6. The lateral control method of claim 1, wherein The lateral control method further comprises: re-determining the neutral rotation angle according to the rotation angle, the front wheel steering angle and the preset steering ratio every preset time length in a second preset time period to obtain a plurality of the neutral rotation angles; filtering a plurality of the neutral rotation angles to obtain a plurality of filtered neutral rotation angles; determining an average value of a plurality of the filtered neutral rotation angles, and determining the average value as a processed neutral rotation angle.

7. The lateral control method of claim 1, wherein The lateral control method further comprises: acquire a historical rotation angle of the steering motor in a target time period, the target time period being from a last sampling period to a current sampling period; determine a corresponding front wheel steering angle change value according to the historical rotation angle; add the front wheel steering angle of the last sampling period and the front wheel steering angle change value to determine a front wheel steering angle prediction value; correct the front wheel steering angle prediction value according to the front wheel steering angle by a Kalman filtering algorithm to obtain a corrected front wheel steering angle.

8. The lateral control method of claim 1, wherein, the target rotation angle of the steering motor is determined according to the target front wheel steering angle, the median rotation angle and the preset steering ratio, including: an initial rotation angle of the steering motor is determined according to a product of the target front wheel steering angle and the preset steering ratio; the initial rotation angle is added to the median rotation angle to obtain the target rotation angle.

9. A processor, comprising: a processor configured to perform the lateral control method for vehicle driving according to any one of claims 1 to 8.

10. A vehicle characterized by comprising: including: a steering wheel; a front wheel; a steering motor corresponding to the steering wheel; and the processor according to claim 9. ​

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