A steering control method and device, vehicle and storage medium

Abstract

This application provides a steering control method, device, vehicle, and storage medium. The method includes: acquiring the actual wheel angle, longitudinal acceleration, and yaw rate of the vehicle; determining a target wheel angle based on a yaw dynamics model using the longitudinal acceleration and yaw rate, wherein the yaw dynamics model aims to reduce the yaw rate to zero; and driving a power steering motor to reduce the deviation between the actual wheel angle and the target wheel angle. It is understood that the embodiments of this application can suppress vehicle drift caused by the motion coupling between the suspension and steering systems, thereby improving straight-line driving stability.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and more specifically to a steering control method, device, vehicle, and storage medium. Background Technology

[0002] In the field of vehicle steering control technology, electric power steering systems detect the torque or steering angle applied by the driver to the steering wheel and control the power steering motor to output auxiliary torque, thereby reducing the effort required for steering. It can be understood that the steering wheel and steering gear are connected via a steering column, and the steering gear converts the rotational motion of the steering wheel into the linear motion of the steering tie rod, which in turn drives the steering wheels to turn. In this process, the transmission relationship between the steering wheel angle and the actual steering wheel angle directly affects the vehicle's straight-line stability and steering response accuracy.

[0003] In related technologies, electric power steering systems commonly use a steering wheel angle sensor installed inside the steering column or steering gear as the angle feedback device. For vehicles with a kinematic coupling between the steering wheels and the suspension system, such as chassis structures where suspension deformation directly alters the geometry of the steering tie rods, there is a structural coupling between the suspension and steering system. Taking a suspension using leaf springs as the elastic element as an example, when the vehicle is loaded, the axle bounces with the elastic element; during braking, the elastic element deforms. Both of these conditions change the geometry of the steering tie rods, thus applying an additional steering angle to the steering wheels unrelated to steering wheel operation.

[0004] Due to the aforementioned additional steering angle, the transmission relationship between the steering wheel angle and the actual steering wheel angle exhibits a dynamically changing characteristic. Electric power steering systems that use the steering wheel angle as the control target cannot know the actual steering wheel angle. When the vehicle is traveling straight, the driver keeps the steering wheel in the center position, but the actual steering wheel angle has already deviated from the straight-line position, causing the vehicle to veer off course. The driver needs to frequently correct the steering wheel to maintain straight-line driving, increasing driving fatigue.

[0005] It should be noted that the information disclosed in the background section of this application is intended only to enhance the understanding of the general background of this application, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] In view of this, this application provides a steering control method, device, vehicle, and storage medium to help solve the technical problem in related technologies where, in vehicles with a kinematic coupling relationship between the steering wheel and the suspension system, the dynamic changes in the transmission relationship between the steering wheel angle and the actual steering wheel angle cause the vehicle to easily veer off course when driving straight, and the driver needs to frequently correct the steering wheel.

[0007] In a first aspect, embodiments of this application provide a steering control method applied to a vehicle, the vehicle including a power steering motor, the method comprising: The actual wheel angle, longitudinal acceleration, and yaw rate of the vehicle are obtained. Based on the longitudinal acceleration and the yaw rate, the target wheel angle is determined using a yaw dynamics model, wherein the yaw dynamics model takes the yaw rate approaching zero as the control objective. The steering assist motor is driven to reduce the deviation between the actual wheel angle and the target wheel angle.

[0008] In this embodiment, by acquiring the actual wheel angle, longitudinal acceleration, and yaw rate, the control system can directly determine the true wheel attitude. With the yaw rate approaching zero as the target, the target wheel angle is calculated using a yaw dynamics model based on the longitudinal acceleration and yaw rate. This target wheel angle reflects the wheel angle required to bring the yaw rate to zero. Furthermore, by comparing the deviation between the actual wheel angle and the target wheel angle and driving the motor to reduce the deviation, a closed-loop control is formed. Since the target wheel angle is dynamically calculated based on the vehicle's motion state, and the actual wheel angle is directly measured, the system can directly adjust the wheel angle, thereby suppressing the interference of the additional steering angle caused by suspension motion coupling on straight-line driving, reducing the vehicle's tendency to veer off course, and lowering the frequency of driver steering wheel corrections.

[0009] In one possible implementation, the vehicle includes a wheel angle sensor mounted between the kingpin and the steering knuckle to detect angular displacement between the kingpin and the steering knuckle; obtaining the actual wheel angle of the vehicle includes: The actual wheel angle of the vehicle is determined based on the angular displacement between the kingpin and the steering knuckle.

[0010] In this embodiment, the installation method described above allows the wheel angle sensor to directly detect the angular displacement of the steering knuckle relative to the kingpin, i.e., the actual deflection angle of the wheel around the kingpin. Since the detection path does not pass through intermediate transmission components such as steering tie rods, the influence of suspension deformation or transmission backlash on the measurement results is reduced, thereby obtaining a more accurate actual wheel angle. Based on the accurate actual angle, the tracking accuracy of the target angle is improved, providing a reliable measurement basis for suppressing wheel deviation.

[0011] In one possible implementation, driving the power steering motor based on the deviation between the actual wheel angle and the target wheel angle includes: The gain coefficient of the PID control algorithm is adjusted according to the vehicle speed and / or the longitudinal acceleration. The deviation between the actual wheel angle and the target wheel angle is input into the PID control algorithm after the gain coefficient is adjusted to determine the motor drive signal; The motor drive signal is output to the power steering motor to drive the power steering motor.

[0012] In this embodiment, by adjusting the PID gain coefficient according to vehicle speed or longitudinal acceleration, the control parameters can be adapted to different vehicle driving conditions. Appropriately increasing the gain at low speeds or with large longitudinal acceleration helps improve response speed, while decreasing the gain at high speeds reduces overshoot and oscillation.

[0013] In one possible implementation, the yaw dynamics model includes the yaw moment balance equations: ; Where a is the distance from the center of mass to the front axle, k1 is the steering wheel lateral stiffness, δ is the wheel angle, m is the vehicle mass, α is the longitudinal acceleration, and I z The moment of inertia of the vehicle's yaw motion. This is the yaw acceleration.

[0014] In this embodiment, the yaw moment balance equation quantifies the physical relationship between wheel angle, longitudinal acceleration, and yaw acceleration into a mathematical expression. Using this equation, the desired target wheel angle can be calculated in reverse based on the current longitudinal acceleration and the desired yaw acceleration. The equation includes an additional yaw moment term caused by longitudinal acceleration, enabling the model to reflect the influence of suspension motion coupling on wheel angle under load or braking conditions. Determining the target wheel angle based on this model helps compensate for additional angles caused by suspension interference, improving the targeting and adaptability of closed-loop control.

[0015] In one possible implementation, before determining the target wheel angle based on the yaw dynamics model, the method further includes: Obtain the vehicle's load information and suspension height information; Based on the load information and the suspension height information, determine the vehicle mass and / or steering wheel lateral stiffness in the yaw moment balance equation.

[0016] In this embodiment, by acquiring load information and suspension height information, the vehicle's current mass distribution and suspension compression state can be identified in real time. This information is used to determine the vehicle mass and steering wheel lateral stiffness in the yaw moment balance equation, allowing the model parameters to be adjusted to follow actual load changes. The updated model can more accurately reflect the vehicle's true dynamic response when calculating the target wheel steering angle, thereby improving the adaptability of steering angle control under different load conditions.

[0017] In one possible implementation, driving the power steering motor based on the deviation between the actual wheel angle and the target wheel angle includes: Get the steering wheel angle and steering wheel torque; Based on the steering wheel angle and the steering wheel torque, determine whether the driver has a steering intention; When it is determined that the driver has no intention to steer, the steering assist motor is driven according to the deviation between the actual wheel angle and the target wheel angle.

[0018] In this embodiment, by acquiring the steering wheel angle and steering wheel torque, it is possible to identify whether the driver is actively operating the steering wheel. Only when the system detects no steering intention from the driver will it drive the motor to correct the steering based on the steering angle deviation; if the driver has a steering intention, no such active intervention is applied. This judgment mechanism helps reduce the output of control torque by the electric power steering system that is opposite to the driver's intention when the driver actively changes lanes or turns, thereby reducing human-machine interaction and improving the smoothness and safety of steering operations.

[0019] In one possible implementation, determining whether the driver intends to steer includes: When the absolute value of the steering wheel angle is less than or equal to the angle threshold and the absolute value of the steering wheel torque is less than or equal to the torque threshold, it is determined that the driver has no intention to steer. When the absolute value of the steering wheel angle is greater than the angle threshold or the absolute value of the steering wheel torque is greater than the torque threshold, it is determined that the driver has a steering intention.

[0020] In this embodiment, setting a steering angle threshold and a torque threshold can accurately identify whether the driver actively operates the steering wheel. When the system detects that the driver intends to turn, it does not intervene, thereby reducing human-machine interaction and improving the smoothness and safety of steering operations.

[0021] Secondly, embodiments of this application provide a steering control method applied to a vehicle, the vehicle including a power steering motor, the method comprising: Obtain the actual wheel angle, lane line information, and vehicle speed of the vehicle; Based on the lane line information, determine the lateral deviation of the vehicle relative to the lane line; The target wheel angle is determined based on the lateral deviation and the vehicle speed; The steering assist motor is driven to reduce the deviation between the actual wheel angle and the target wheel angle.

[0022] In this embodiment, the lateral deviation of the vehicle relative to the lane line is calculated by acquiring lane line information, and the target wheel angle is determined by combining the vehicle speed. Then, closed-loop driving is performed using the actual wheel angle as feedback, which can directly adjust the wheel angle to correct the driving trajectory. This method does not rely on the transmission relationship between the steering wheel angle and the wheel angle, which helps to reduce the impact of transmission nonlinearity caused by suspension motion coupling on lateral control accuracy, thereby improving the accuracy and stability of lane following under intelligent assisted driving.

[0023] In one possible implementation, determining the target wheel angle based on the lateral deviation and the vehicle speed includes: Based on the lateral deviation and the vehicle speed, determine the desired vehicle yaw rate; Obtain the longitudinal acceleration of the vehicle; The target wheel rotation angle is calculated using a yaw dynamics model based on the desired yaw rate and the longitudinal acceleration.

[0024] In this embodiment, the lateral deviation and vehicle speed are converted into the desired yaw rate, and then combined with the longitudinal acceleration to solve the target wheel angle using a yaw dynamics model. This process ensures that the target wheel angle conforms to the physical characteristics of vehicle yaw motion, helping to reduce the risk of sudden angle changes or oscillations, thereby improving the smoothness and control accuracy of lateral trajectory tracking.

[0025] Thirdly, embodiments of this application provide a steering control device, including: The information acquisition module is used to acquire the actual wheel angle of the vehicle, the longitudinal acceleration of the vehicle, and the yaw rate of the vehicle. The target wheel rotation angle determination module is used to determine the target wheel rotation angle based on the longitudinal acceleration and the yaw rate, according to a yaw dynamics model, wherein the yaw dynamics model takes the yaw rate approaching zero as the control target; The power steering motor drive module is used to drive the power steering motor to reduce the deviation between the actual wheel angle and the target wheel angle.

[0026] Fourthly, embodiments of this application provide a vehicle, including: processor; Memory; And a computer program, wherein the computer program is stored in the memory, the computer program including instructions that, when executed by the processor, cause the vehicle to perform the method described in either the first aspect or the second aspect.

[0027] Fifthly, embodiments of this application provide a computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform the method described in either the first or second aspect.

[0028] Understandably, the steering control device provided in the third aspect, the vehicle provided in the fourth aspect, and the computer-readable storage medium provided in the fifth aspect are all used to perform some or all of the methods provided in this application. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods, and will not be repeated here. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of an application scenario provided by an embodiment of this application.

[0031] Figure 2 This is a flowchart illustrating a steering control method provided in an embodiment of this application.

[0032] Figure 3 This is a schematic diagram of the structure of a wheel angle sensor provided in an embodiment of this application.

[0033] Figure 4 This is a schematic diagram showing the installation position of a wheel angle sensor provided in an embodiment of this application.

[0034] Figure 5 This is a schematic diagram of the electrical connection of a wheel angle sensor provided in an embodiment of this application.

[0035] Figure 6 This is a flowchart illustrating another steering control method provided in an embodiment of this application.

[0036] Figure 7 This is a schematic diagram of an adaptive steering control process provided in an embodiment of this application.

[0037] Figure 8 This is a flowchart illustrating another steering control method provided in an embodiment of this application.

[0038] Figure 9 A flowchart of another steering control method provided in an embodiment of this application.

[0039] Figure 10 This is a schematic diagram of a steering control device provided in an embodiment of this application.

[0040] Figure 11 This is a structural schematic diagram of a vehicle provided in an embodiment of this application. Detailed Implementation

[0041] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0042] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0043] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0044] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0045] To facilitate understanding, specific application scenarios will be illustrated below.

[0046] See Figure 1 This is a schematic diagram illustrating an application scenario provided by an embodiment of this application. For example... Figure 1 As shown, this application scenario includes: an electric power steering system 101, a front axle 102, a steering tie rod 103, steering wheels 104, and a leaf spring suspension 105. The electric power steering system 101 includes a power steering motor and a steering gear. The output end of the steering gear is connected to the steering knuckle on the front axle 102 via the steering tie rod 103, used to transmit the rotational torque of the motor to the steering wheels 104. The steering wheels 104 are mounted at both ends of the front axle 102 and can deflect around the kingpin axis. The leaf spring suspension 105, as an elastic element, connects the vehicle frame and the front axle 102, used to support the vehicle body and buffer road impacts. During vehicle operation, when the driver turns the steering wheel or the driver assistance system issues a lateral command, the electric power steering system 101 generates a corresponding assist torque, which drives the steering wheels 104 to deflect via the steering tie rod 103, thereby changing the vehicle's direction of travel.

[0047] For vehicles where there is a kinematic coupling between the steering wheels and the suspension system, such as Figure 1 The non-independent suspension structure shown uses leaf spring suspension 105. The deformation of the suspension directly alters the geometric position of the steering tie rod 103. Specifically, when the vehicle is loaded, the leaf spring suspension 105 is compressed, and the front axle 102 moves upward relative to the frame, causing a change in the fixed point position of the steering tie rod 103. This applies an additional steering angle to the steering wheel 104, independent of steering wheel operation. Similarly, under braking conditions, the leaf spring suspension 105 undergoes S-shaped deformation, which also causes a change in the geometric position of the steering tie rod 103, further generating an additional steering angle. This additional steering angle makes the angular transmission relationship between the steering wheel and the steering wheel 104 non-linear and dynamically changing with load and braking conditions.

[0048] To address the aforementioned issues, this application embodiment adds a wheel angle sensor. This wheel angle sensor is used to directly detect the actual wheel angle of the steering wheel 104. Simultaneously, the electric power steering system 101 acquires the steering wheel angle through an internally integrated steering wheel angle sensor and obtains the vehicle's longitudinal acceleration and yaw rate via a controller area network bus or other means. Based on this, a target wheel angle is calculated using a yaw dynamics model with the yaw rate approaching zero as the objective. The power steering motor is then driven based on the deviation between the actual wheel angle and the target wheel angle, forming a closed-loop control independent of the steering wheel angle. It is understood that because the target wheel angle is dynamically calculated based on the vehicle's motion state, and the actual wheel angle is directly measured, the system can directly adjust the wheel angle, thereby suppressing the interference of additional steering angles caused by suspension motion coupling on straight-line driving, reducing vehicle deviation tendencies, and decreasing the frequency of driver steering wheel corrections. Specifically, detailed descriptions are provided below in conjunction with the accompanying drawings and specific embodiments.

[0049] See Figure 2 This is a flowchart illustrating a steering control method provided in an embodiment of this application. This method can be applied to the application scenarios described above, such as... Figure 2 As shown, it mainly includes the following steps.

[0050] Step S201: Obtain the actual wheel angle, longitudinal acceleration, and yaw rate of the vehicle.

[0051] In this embodiment, the actual wheel angle, longitudinal acceleration, and yaw rate of the vehicle during actual driving are first obtained. The actual wheel angle refers to the angle by which the steering wheel deflects relative to the vehicle's longitudinal axis. Longitudinal acceleration refers to the rate of change of the vehicle's velocity along its direction of travel, reflecting whether the vehicle is accelerating, moving at a constant speed, or decelerating; this signal is typically provided by an inertial measurement unit or an electronic stability control system. Yaw rate refers to the angular velocity of the vehicle's rotation about its vertical axis, characterizing whether the front of the vehicle rotates relative to its direction of travel; for example, the yaw rate is positive when the vehicle veers to the right and negative when it veers to the left.

[0052] Taking a straight-line driving scenario as an example, when the driver presses the brake pedal but does not turn the steering wheel, due to the motion coupling between the suspension and steering system, the actual wheel angle may have deviated from zero. At the same time, the yaw rate changes from zero to a non-zero value, and the longitudinal acceleration becomes negative. Obtaining these three parameters provides the input basis for subsequent calculation of the target wheel angle.

[0053] It should be noted that the order in which the actual wheel rotation angle, longitudinal acceleration, and yaw rate are obtained is not limited; the three can be obtained in parallel or in any order.

[0054] In one possible implementation, the actual wheel angle obtained in step S201 depends on the measurement data provided by the wheel angle sensor. Specifically, in this embodiment, the wheel angle sensor is installed between the kingpin of the steering wheel and the steering knuckle. To facilitate understanding of the specific measurement method of the wheel angle, it will be described below with reference to the accompanying drawings.

[0055] See Figure 3 This is a schematic diagram of the structure of a wheel angle sensor provided in an embodiment of this application. Figure 3 As shown, the wheel angle sensor 301 adopts a fully enclosed structure, containing a detection chip and magnetic components internally, and a rotor and housing externally. The rotor of the sensor engages with the kingpin shaft, while the housing is fixedly connected to the steering knuckle. When the steering knuckle rotates around the kingpin axis, a relative angular displacement is generated between the rotor and the housing, and the sensor outputs an electrical signal based on this angular displacement.

[0056] See Figure 4 This is a schematic diagram illustrating the installation position of a wheel angle sensor according to an embodiment of this application. Figure 4As shown, the wheel angle sensor 301 is fixed to the steering knuckle 404 by mounting bolts 401. The positioning circular surface at the bottom of the wheel angle sensor 301 housing is coaxially positioned with the kingpin mounting hole on the steering knuckle. The sensor rotor can engage with the rectangular groove at the end of the kingpin shaft 403 through a flat rectangular structure, ensuring no relative rotation between the two. A sealing ring 402 is provided between the kingpin shaft 403 and the steering knuckle 404 to prevent water and dust intrusion. When the wheel deflects, the steering knuckle 404, together with the wheel angle sensor 301 housing, rotates around the kingpin shaft 403, while the rotor remains stationary with the kingpin shaft 403. The relative angular displacement between the housing and the rotor is the actual deflection angle of the steering wheel. The wheel angle sensor 301 converts this angular displacement into an electrical signal, which is transmitted to the controller of the electric power steering system via a signal line.

[0057] In actual assembly, the wheel angle sensor can be placed at either the upper or lower end of the kingpin, as long as it can detect the relative angular displacement between the steering knuckle and the kingpin. Furthermore, the sensor's detection principle can employ the tunneling magnetoresistance effect or the inductive eddy current effect. With this installation method, the sensor can directly obtain the actual wheel deflection angle without passing through intermediate transmission components such as steering tie rods, thereby reducing the influence of suspension deformation or transmission backlash on the measurement results.

[0058] In practical applications, in addition to the mechanical mounting method of the wheel angle sensor described above, this application embodiment also provides a detailed description of the electrical connection method of the wheel angle sensor. See [link to relevant documentation]. Figure 5 This is a schematic diagram of the electrical connections for a wheel angle sensor provided in an embodiment of this application. Figure 5 As shown, the electric power steering system 501 integrates a controller and a power management module (not shown), and the wheel angle sensor 502 is connected to the electric power steering system 501 via a signal line.

[0059] Due to the limited installation space available near the steering wheels, the size of the wheel angle sensor is strictly limited. Therefore, the sensor typically does not have a separate power conversion module and communication processing unit. In this embodiment, the wheel angle sensor is powered by the electric power steering system. The electric power steering system outputs a stable DC voltage through its internal power management module, which is then transmitted to the wheel angle sensor via a power line to meet the sensor's power requirements. Simultaneously, the angular displacement signal detected by the wheel angle sensor is converted into an electrical signal and transmitted back to the controller of the electric power steering system via a signal line. The controller receives and analyzes this electrical signal to obtain the specific value of the actual wheel angle.

[0060] Step S202: Determine the target wheel angle based on the longitudinal acceleration and yaw rate using the yaw dynamics model.

[0061] In this embodiment, the target wheel rotation angle is determined using a yaw dynamics model based on the acquired longitudinal acceleration and yaw rate. The yaw dynamics model is a control model that describes the dynamic relationship between longitudinal acceleration, yaw rate, and wheel rotation angle. The model aims to achieve a yaw rate approaching zero.

[0062] It should be noted that in vehicle dynamics, if a wheel has a non-zero steering angle, a lateral force will be generated. This lateral force will cause yaw acceleration, which in turn will change the yaw rate. Therefore, in steady-state straight-line driving, when the yaw rate is zero, the wheel steering angle is usually also zero; otherwise, the vehicle could not maintain stable straight-line motion. Based on this principle, the target wheel steering angle determined in this step is actually an intermediate command value in a dynamic adjustment process. The purpose of the control system is to continuously adjust the wheel steering angle so that the yaw rate gradually decreases and eventually approaches zero, while the wheel steering angle also approaches zero.

[0063] For example, when a vehicle is traveling at a constant speed on a straight road, the yaw rate is zero, and the wheel angle is zero. If braking is applied at this time, the suspension deformation may pull the steering wheel off course by a small angle, causing the wheel angle to deviate from zero. This non-zero angle then generates a lateral force, causing the yaw rate to increase from zero, and the vehicle to veer to the right. The controller detects the non-zero yaw rate and negative longitudinal acceleration, and inputs these parameters into the yaw dynamics model. Based on the current motion state, the yaw dynamics model calculates in reverse the direction and angle of the wheel angle to generate a yaw acceleration opposite to the current direction of rotation, thereby gradually reducing the yaw rate. This calculated angle is the target wheel angle. Since the target wheel angle is opposite to the current actual wheel angle, the power steering motor drives the wheel to rotate towards the target angle, and the actual wheel angle decreases accordingly. As the actual angle decreases, the lateral force weakens, the yaw acceleration reverses, and the yaw rate gradually decreases. When the yaw rate approaches zero, the actual wheel rotation angle also approaches zero, and the vehicle resumes stable straight-line driving.

[0064] Taking a vehicle traveling on a sloping road as an example, the lateral slope of the road causes the vehicle to tend to veer towards the lower side, resulting in a non-zero yaw rate. The controller acquires this yaw rate and the current longitudinal acceleration (which may be positive or negative), and calculates the target wheel angle using a yaw dynamics model. The magnitude and direction of this target angle depend on the sign of the longitudinal acceleration and the direction of the yaw rate, aiming to generate an appropriate reverse yaw acceleration to suppress yaw. Through this closed-loop adjustment, the yaw rate is effectively suppressed, and the wheel angle returns to zero.

[0065] Therefore, the target wheel angle determined above is an instantaneous command in the dynamic suppression process. It changes in coordination with the yaw rate and eventually returns to zero in steady state, thus ensuring the straight-line driving stability of the vehicle.

[0066] In one possible implementation, embodiments of this application provide a specific mathematical form of the model, namely the yaw moment balance equation. Before introducing the yaw moment balance equation, it is necessary to first explain what steering-related forces the vehicle experiences during driving.

[0067] When a wheel turns at an angle, a lateral force is generated in the contact area between the tire and the road surface. This lateral force is perpendicular to the direction of wheel travel. Since the steering wheel is located on the front axle, and the vehicle's center of gravity is typically behind the front axle, the lateral force at the front wheel generates a rotational torque about the center of gravity. This torque attempts to rotate the vehicle about its vertical axis. The magnitude of this rotational torque depends on the magnitude of the lateral force and the distance from the center of gravity to the front axle. The lateral force itself is related to the wheel turning angle and the tire's lateral stiffness, which reflects the tire's ability to resist lateral deformation.

[0068] Besides the rotational torque generated by lateral forces, longitudinal acceleration also affects the yaw motion of a vehicle. Longitudinal acceleration refers to the vehicle's acceleration or deceleration in its direction of travel; for example, pressing the accelerator pedal produces positive acceleration, and pressing the brake pedal produces negative acceleration. Longitudinal acceleration causes a longitudinal force to act on the wheels in the direction of travel. When the wheels rotate through a certain angle, a portion of the longitudinal force is decomposed into a direction perpendicular to the vehicle's longitudinal axis, thus creating an additional rotational torque. In other words, even if the driver does not actively turn the steering wheel, during braking or acceleration, if there is a slight rotation of the wheels, the longitudinal force will generate a torque that attempts to rotate the vehicle. This torque is called the additional rotational torque.

[0069] The rotational motion of a vehicle about its vertical axis follows the rotational law: the total rotational torque acting on the vehicle is equal to the vehicle's yaw moment of inertia multiplied by the yaw acceleration. The yaw moment of inertia reflects the vehicle's resistance to rotational motion, while the yaw acceleration is the rate of change of the yaw rate. A yaw rate of zero indicates no rotational motion, while a change in yaw rate signifies that the vehicle has begun or stopped rotating. Based on the above mechanical relationships, this application uses the following yaw moment balance equation to describe the relationship between wheel angle, longitudinal acceleration, and yaw acceleration: .

[0070] Where a is the distance from the center of mass to the front axle, k1 is the steering wheel lateral stiffness, δ is the wheel angle, m is the vehicle mass, α is the longitudinal acceleration, and I... z The moment of inertia of the vehicle's yaw motion. This is the yaw acceleration.

[0071] The first term on the left side of the equation This corresponds to the rotational torque caused by the lateral force generated by the wheel's rotation angle. Specifically, This represents the lateral force generated by the wheel's rotation angle. Multiplying this by the lever arm 'a' gives the rotational torque generated by this lateral force about the center of mass. The second term on the left-hand side of the equation... This corresponds to the additional rotational torque caused by longitudinal acceleration. The total longitudinal force acting on the vehicle, divided by 4 to represent the longitudinal force evenly distributed to the four wheels, multiplied by... The longitudinal force is decomposed into directions perpendicular to the vehicle's longitudinal axis, and then multiplied by the lever arm α to obtain the additional rotational torque. It should be noted that using a denominator of 4 is a balanced distribution method; in practical applications, other distribution ratios can be used depending on the load distribution on different axles. (Right side of the equation) This represents the inertial torque, which is the torque required for a vehicle to resist rotational motion.

[0072] To determine the target wheel angle using the above equation, the control system employs a reverse solution method. Since the control objective is to bring the yaw rate towards zero, when the measured yaw rate is not zero, a yaw acceleration in the opposite direction to this yaw rate is required. The magnitude of this yaw acceleration can be determined based on the absolute value of the current yaw rate through a pre-calibrated relationship, such as a proportional relationship; the larger the absolute value of the current yaw rate, the larger the absolute value of the required yaw acceleration. Substituting this yaw acceleration value into the right side of the equation, and simultaneously substituting the currently measured longitudinal acceleration into the left side of the equation, the only unknown in the equation is the wheel angle. Solving this equation yields the target wheel angle required to bring the yaw rate towards zero. As the yaw rate gradually decreases and approaches zero, the required yaw acceleration also approaches zero. The calculated target wheel angle then approaches zero, consistent with the physical requirement that the wheel angle must be zero during steady-state straight-line driving.

[0073] It should be noted that the yaw acceleration on the right side of the equation is an intermediate calculation quantity, not directly obtained from the sensor measurement, but rather an expected value calculated based on the control target and the current yaw rate.

[0074] To further improve the accuracy of the model under different load conditions, this application embodiment introduces a correction step for the yaw dynamics model parameters before determining the target wheel rotation angle based on the yaw dynamics model. The following is in conjunction with... Figure 6 Please provide an explanation.

[0075] See Figure 6 This is a flowchart illustrating another steering control method provided in an embodiment of this application. Figure 6 As shown, it mainly includes the following steps S601 and S602.

[0076] In step S601, the vehicle's load information and suspension height information are first acquired. The load information can be measured by a load sensor mounted on the leaf spring suspension or indirectly obtained through the pressure signal from the air suspension system. The suspension height information can be detected using a height sensor installed between the vehicle frame and the axle. For example, when the vehicle is loaded with cargo, the leaf springs are compressed, the suspension height decreases, and the load information shows an increase in mass; when the vehicle is unloaded, the suspension height increases, and the load information shows a decrease in mass.

[0077] In step S602, based on the load information and suspension height information obtained in step S601, the vehicle mass and steering wheel lateral stiffness in the yaw moment balance equation are determined. The vehicle mass is directly related to the load information and can be obtained by adding the unloaded mass and the loaded mass. The steering wheel lateral stiffness is affected by the vertical load; as the load increases, the tire contact pressure increases, and the lateral stiffness usually increases accordingly. A pre-calibrated mapping relationship can be established between the two. For example, when a decrease in suspension height is detected and the load information shows an increase in mass, the controller will increase the vehicle mass parameter in the equation and simultaneously increase the steering wheel lateral stiffness parameter; conversely, when the suspension height increases and the load decreases, the above parameters will be decreased accordingly. As a parallel implementation, only the vehicle mass can be adjusted without adjusting the lateral stiffness, or only the lateral stiffness can be adjusted without adjusting the mass; both methods can improve the model accuracy to some extent. Through the above parameter corrections, the yaw moment balance equation can more accurately reflect the vehicle dynamics characteristics under the current load state, thereby improving the accuracy of the target wheel steering angle calculation.

[0078] Step S203: Drive the power steering motor to reduce the deviation between the actual wheel angle and the target wheel angle.

[0079] In this embodiment of the application, the deviation between the determined target wheel angle and the actual wheel angle is calculated, and the power steering motor is driven according to the deviation to make the actual wheel angle gradually approach the target wheel angle, thereby reducing the deviation.

[0080] Specifically, the deviation between the actual wheel angle and the target wheel angle reflects the difference between the current wheel posture and the control target. For example, in the example of brake pull, the actual wheel angle may be positive (turning to the right), while the target wheel angle calculated through step S202 above is negative (turning to the left is needed to suppress yaw rate). In this case, the deviation is negative and has a large absolute value. The control system converts this deviation into a drive command for the power steering motor, controlling the motor to output torque in the corresponding direction, driving the steering gear and steering tie rod, causing the wheel to turn in the direction that reduces the deviation. As the motor drives, the actual wheel angle gradually approaches the target wheel angle, and the deviation gradually decreases. When the actual wheel angle approaches the target wheel angle, the yaw acceleration generated by the vehicle is in the opposite direction to the current yaw rate, the yaw rate begins to decrease, and the pull-off trend is suppressed.

[0081] In one possible implementation, the driving process can employ closed-loop control, continuously monitoring the deviation between the actual wheel angle and the target wheel angle, and adjusting the motor output in real time based on changes in the deviation. When the deviation is large, the motor outputs a larger driving torque, enabling rapid wheel response; when the deviation is small, the motor outputs a smaller driving torque to avoid overshoot. Through this continuous deviation adjustment, the actual wheel angle dynamically follows changes in the target wheel angle until the yaw rate approaches zero. At this point, the target wheel angle approaches zero, and the actual wheel angle also approaches zero, allowing the vehicle to resume stable straight-line driving.

[0082] It can be understood that the aforementioned method of adjusting the motor output based on deviation is used when driving the power steering motor. To further improve the adaptability and smoothness of deviation adjustment, the embodiments of this application also adaptively adjust the control parameters during the driving process. This will be explained below with specific examples.

[0083] During actual driving, vehicle speed and longitudinal acceleration change, resulting in variations in the steering system's response characteristics at different speeds and under different acceleration / deceleration conditions. For example, at high speeds, the steering response is more sensitive; excessive motor drive may cause wheel angle overshoot, leading to vehicle swaying. Conversely, at low speeds, the steering response is relatively sluggish; insufficient drive may result in slow deviation convergence, affecting the effectiveness of lane departure prevention. Similarly, when longitudinal acceleration is positive (acceleration) or negative (braking), the adhesion between the tires and the road surface changes, altering the steering wheel's lateral deflection characteristics and consequently affecting the steering angle control response requirements.

[0084] Based on the above considerations, this application's embodiments introduce a proportional-integral-derivative (PID) control algorithm when driving the power steering motor, and adjust the gain coefficient of the PID control algorithm according to at least one parameter, vehicle speed and longitudinal acceleration. Specifically, when the vehicle speed is high, the gain coefficient can be appropriately reduced to avoid excessive driving torque from the motor causing the wheel angle to change too quickly; when the vehicle speed is low, the gain coefficient can be appropriately increased to ensure that deviations can be eliminated in time. Similarly, when the absolute value of longitudinal acceleration is large (i.e., rapid acceleration or braking), the suspension deformation is more significant, and the additional disturbance to the steering wheel is greater. In this case, the gain coefficient can be appropriately increased to enhance the control force; when the longitudinal acceleration is close to zero, the gain coefficient can be restored to the normal value.

[0085] As a parallel implementation method, the gain coefficient can be adjusted solely based on vehicle speed, without considering longitudinal acceleration; or it can be adjusted solely based on longitudinal acceleration, without considering vehicle speed. Both methods can improve control adaptability under different operating conditions to some extent. For example, in a constant-speed driving scenario on a highway, the vehicle speed is high and the longitudinal acceleration is close to zero. In this case, adjusting the gain coefficient to a lower value based on the vehicle speed can make the lane-keeping process smoother. In a fully loaded downhill braking scenario, the longitudinal acceleration is negative and has a large absolute value. In this case, adjusting the gain coefficient to a higher value based on the longitudinal acceleration can make the system respond more quickly to wheel angle deviation caused by suspension deformation and suppress deviation in a timely manner.

[0086] After determining the gain coefficient, the deviation between the actual wheel angle and the target wheel angle is input into the PID control algorithm after the gain coefficient is adjusted. This algorithm calculates the motor drive signal. The output of the PID control algorithm is the current or voltage command to be applied to the power steering motor, which causes the motor to output the corresponding driving torque. The calculated motor drive signal is output to the power steering motor, which then generates the corresponding assist torque. This torque drives the steering wheel to deflect through the steering gear and steering tie rod, thereby gradually bringing the actual wheel angle closer to the target wheel angle.

[0087] For ease of understanding, see Figure 7 This is a schematic diagram of an adaptive steering control process provided in an embodiment of this application. Figure 7As shown, vehicle speed and longitudinal acceleration are input to the gain coefficient adjustment module, which determines the gain coefficient of the PID control algorithm based on these parameters. The actual wheel angle is measured by a wheel angle sensor, while the target wheel angle is calculated using the yaw moment balance equation based on longitudinal acceleration and yaw rate. The difference between the actual and target wheel angles is the deviation, which is fed into the PID control algorithm after gain coefficient adjustment. The PID control algorithm outputs a motor drive signal to the power steering motor, which drives the steering wheel to deflect. The wheel angle sensor continuously detects the actual deflection angle of the steering wheel, forming a closed-loop feedback. Through this adaptive drive method, the output of the power steering motor can adapt to the response requirements under different vehicle speeds and longitudinal acceleration conditions, thereby ensuring the effect of lane departure suppression while reducing overshoot and oscillation, and improving driving smoothness.

[0088] In practical applications, the driver may be actively performing steering maneuvers, such as changing lanes or turning. If the control system still forcibly corrects the wheel angle based on the deviation, it may generate a control torque opposite to the driver's intention, causing human-machine conflict and affecting driving comfort and safety. Therefore, this application's embodiment further introduces a mechanism for judging the driver's steering intention before driving the power steering motor.

[0089] Specifically, the control system acquires the steering wheel angle and steering wheel torque. The steering wheel angle reflects the rotation angle of the steering wheel relative to its center position, and the steering wheel torque reflects the magnitude of the torsional torque applied to the steering wheel by the driver. In one possible implementation, steering angle thresholds and torque thresholds are preset. When the absolute value of the steering wheel angle is less than or equal to the steering angle threshold and the absolute value of the steering wheel torque is less than or equal to the torque threshold, it is determined that the driver has no steering intention; when the absolute value of the steering wheel angle is greater than the steering angle threshold or the absolute value of the steering wheel torque is greater than the torque threshold, it is determined that the driver has a steering intention. For example, the steering angle threshold can be set to 5°, and the torque threshold can be set to 1N. M, the actual value of which can be calibrated according to the vehicle model. Using the above threshold method, it is possible to accurately identify whether the driver is actively operating the steering wheel.

[0090] When the system determines that the driver has no intention to steer, it activates the power steering motor based on the deviation between the actual wheel angle and the target wheel angle to perform the aforementioned deviation suppression control. When the system determines that the driver has a steering intention, it suspends or reduces the intensity of active intervention based on the deviation to avoid interfering with the driver's operation.

[0091] As a parallel implementation method, the driver's steering intention can also be determined solely based on the steering wheel angle, without using steering wheel torque. For example, a steering intention is considered present when the absolute value of the steering wheel angle exceeds a preset angle; otherwise, it is considered absent. Another method is to determine the intention based on the rate of change of steering wheel torque. A large rate of change indicates that the driver is rapidly turning the steering wheel, at which point intervention should be paused. Different judgment strategies can be selected based on the actual calibration results of the vehicle, and this application does not impose specific restrictions on this.

[0092] Through the aforementioned driver steering intention judgment mechanism, the embodiments of this application can reduce unnecessary intervention when the driver actively steers, while ensuring the effect of lane deviation suppression, thereby improving the smoothness and safety of human-machine collaboration.

[0093] It should be noted that the embodiments described above mainly address the vehicle drift problem caused by the motion coupling of the suspension and steering systems under manual driving conditions, providing a straight-line stability control method based on closed-loop wheel angle. During the above control process, the driver always controls the vehicle's direction of travel, and the control system only assists in suppressing drift when the driver has no steering intention. Furthermore, this application also provides a steering control method suitable for assisted driving conditions. Specifically, when the vehicle activates a lateral assist driving function that automatically follows the lane, the control system automatically adjusts the steering wheel deflection angle to keep the vehicle within the lane lines or along the desired trajectory. The method will be described below with specific steps.

[0094] For details, see Figure 8 This is a schematic flowchart of another steering control method provided in an embodiment of this application. As shown in the figure, the following steps are illustrated.

[0095] Step S801: Obtain the vehicle's actual wheel angle, lane line information, and vehicle speed.

[0096] Understandably, in assisted driving mode, the control system first acquires the vehicle's actual wheel angle, lane information, and vehicle speed. Lane information refers to data such as the position, shape, and type of road lane lines collected by visual sensors like onboard cameras, typically expressed as image coordinates or parametric curves. The actual wheel angle is directly measured by the wheel angle sensor mentioned earlier.

[0097] Step S802: Determine the lateral deviation of the vehicle relative to the lane line based on the lane line information.

[0098] In this embodiment, the control system determines the lateral deviation of the vehicle relative to the lane lines based on the acquired lane line information. Lateral deviation refers to the vertical distance between the vehicle's current position and the lane centerline. For example, when the vehicle is traveling on a straight highway, the camera captures the positions of the lane lines on both sides, and an image processing algorithm calculates the distance between the vehicle's center point and the lane centerline. If the vehicle deviates to the right, the lateral deviation is positive; if it deviates to the left, the lateral deviation is negative.

[0099] Step S803: Determine the target wheel angle based on the lateral deviation and vehicle speed.

[0100] In this embodiment, after obtaining the lateral deviation, the control system determines the target wheel steering angle based on the lateral deviation and vehicle speed. This target wheel steering angle reflects the front wheel deflection angle required to bring the vehicle back to the lane centerline from its current deviation position. Generally, the larger the lateral deviation, the larger the steering angle adjustment required; the higher the vehicle speed, the smaller the steering angle adjustment should be to avoid vehicle swaying.

[0101] One approach is to use a proportional control principle, multiplying the lateral deviation by a gain coefficient that is inversely proportional to the vehicle speed to obtain the desired yaw rate or directly obtain the target wheel angle.

[0102] Of course, in one possible implementation, the lateral deviation can be converted into the desired yaw rate, and then combined with the longitudinal acceleration, and the target wheel rotation angle can be solved using the yaw dynamics model described above.

[0103] Specifically, in assisted driving mode, the vehicle needs to return to the lane centerline from its current deviation position. This process essentially involves changing the vehicle's direction of travel by generating appropriate yaw motion. First, the lateral deviation is converted into a desired yaw rate; that is, the angular velocity at which the vehicle should rotate to eliminate the lateral deviation. For example, when the vehicle deviates significantly from the lane centerline, a larger yaw rate is needed for rapid correction; when the deviation is small, only a smaller yaw rate is needed for fine-tuning. Simultaneously, the higher the vehicle speed, the greater the rate of change of lateral displacement produced by the same yaw rate. Therefore, the desired yaw rate should decrease appropriately as the vehicle speed increases to avoid overcorrection. Based on these relationships, the control system determines the desired yaw rate according to the lateral deviation and vehicle speed through a pre-calibrated mapping relationship or proportional control law.

[0104] After determining the desired yaw rate, the control system further acquires the vehicle's longitudinal acceleration. As mentioned earlier, the yaw dynamics model can describe the physical relationship between wheel angle, longitudinal acceleration, and yaw acceleration. In this step, the control system uses the desired yaw rate as the control target and sets the desired yaw acceleration. Since the desired yaw rate is a non-zero value, the control system needs to determine the desired yaw acceleration based on the deviation between the current yaw rate and the desired yaw rate, for example, by using proportional control to gradually track the desired value from the actual yaw rate. Substituting the desired yaw acceleration and the currently measured longitudinal acceleration into the yaw moment balance equation and solving the equation in reverse, the required target wheel angle can be obtained.

[0105] Taking a vehicle driving on a curve as an example, the camera detects the lane curvature and the vehicle's lateral deviation from the lane centerline. The control system calculates the desired yaw rate as positive based on the curvature, vehicle speed, and lateral deviation, indicating a need to turn right to follow the curve. Simultaneously, the current longitudinal acceleration is acquired; if the vehicle is at a constant speed, the longitudinal acceleration is close to zero. Substituting the desired yaw rate, corresponding yaw acceleration, and longitudinal acceleration into the yaw moment balance equation, the calculated target wheel angle is positive, indicating a need to turn right by a certain angle. The actual wheel angle sensor detects the current wheel deflection angle and, through closed-loop drive, brings the wheel to the target angle, causing the vehicle to generate the desired yaw rate and travel along the curve. When the lateral deviation approaches zero, the desired yaw rate also approaches the steady-state value determined by the lane curvature, and the target wheel angle adjusts accordingly, stabilizing the vehicle near the lane centerline.

[0106] Step S804: Drive the power steering motor to reduce the deviation between the actual wheel angle and the target wheel angle.

[0107] In this embodiment, after determining the target wheel angle, the control system obtains the deviation between the actual wheel angle and the target wheel angle, and drives the power steering motor according to the deviation to reduce the deviation. This driving process can employ the PID control algorithm described above, and adjust the gain coefficient according to vehicle speed or longitudinal acceleration. Through closed-loop feedback of the actual wheel angle, the control system can enable the steering wheel to accurately follow the target wheel angle, thereby gradually guiding the vehicle to the vicinity of the lane centerline and maintaining it in that position.

[0108] It is understood that, through the above-described method, this embodiment of the application directly uses the actual wheel turning angle as the control object in assisted driving mode, reducing the impact of the nonlinear transmission relationship between the steering wheel angle and wheel turning angle caused by the motion coupling of the suspension and steering system on the lateral control accuracy, thereby improving the accuracy and stability of lane following. This control method is applicable to both lane centering assist and lane keeping assist, as well as other lateral control scenarios.

[0109] For ease of understanding, see Figure 9 The figure shows a flowchart of another steering control method provided in this application embodiment. As shown, it mainly includes the following steps.

[0110] Step S901: Obtain the vehicle's actual wheel angle, longitudinal acceleration, yaw rate, vehicle speed, steering wheel angle, steering wheel torque, and lane line information.

[0111] Step S902: Determine whether the vehicle is in the assisted driving lateral control mode.

[0112] If in assisted driving mode, proceed to steps S903 to S906; if in manual driving mode, proceed to steps S907 to S911.

[0113] Step S903: Determine the lateral deviation of the vehicle relative to the lane line based on the lane line information.

[0114] Step S904: Determine the desired yaw rate based on the lateral deviation and vehicle speed.

[0115] Step S905: Obtain the longitudinal acceleration, and calculate the target wheel rotation angle using the yaw moment balance equation based on the desired yaw rate and longitudinal acceleration.

[0116] Step S906: Based on the deviation between the actual wheel angle and the target wheel angle, drive the power steering motor to reduce the deviation, and return to step S901.

[0117] Step S907: Determine whether the driver intends to steer based on the steering wheel angle and steering wheel torque.

[0118] If the driver intends to turn, return to step S901; if there is no intention to turn, proceed to steps S908 to S911.

[0119] Step S908: Calculate the target wheel rotation angle using the yaw moment balance equation based on the longitudinal acceleration and yaw rate, where the equation takes the yaw rate approaching zero as the control target.

[0120] Step S909: Adjust the gain coefficient of the proportional-integral-derivative control algorithm according to the vehicle speed and longitudinal acceleration.

[0121] Step S910: Calculate the deviation between the actual wheel rotation angle and the target wheel rotation angle, input the deviation into the proportional-integral-derivative control algorithm after the gain coefficient is adjusted, and generate the motor drive signal.

[0122] Step S911: Output the motor drive signal to the power steering motor to drive the power steering motor to reduce the deviation, and return to step S901.

[0123] For detailed information, please refer to the specific description in the above method embodiment section. For the sake of brevity, this application will not repeat the details here.

[0124] Corresponding to the above embodiments, this application also provides a steering control device. Specifically, see [link to relevant documentation]. Figure 10 This is a schematic diagram of a steering control device provided in an embodiment of this application. As shown in the figure, the steering control device 1000 is illustrated. Specifically, the steering control device 1000 includes: an information acquisition module 1001, used to acquire the actual wheel angle of the vehicle, the longitudinal acceleration of the vehicle, and the yaw rate of the vehicle; a target wheel angle determination module 1002, used to determine the target wheel angle based on the longitudinal acceleration and yaw rate using a yaw dynamics model; and a steering assist motor drive module 1003, used to drive the steering assist motor to reduce the deviation between the actual wheel angle and the target wheel angle.

[0125] For detailed information, please refer to the specific description in the above method embodiment section. For the sake of brevity, this application will not repeat the details here.

[0126] Corresponding to the above embodiments, this application also provides a structural schematic diagram of a vehicle. See also... Figure 11 This is a schematic diagram of a vehicle structure provided in an embodiment of this application. The vehicle 1100 may include a processor 1101, a memory 1102, and a communication unit 1103. These components communicate through one or more buses. Those skilled in the art will understand that the structure of the vehicle shown in the figure does not constitute a limitation on the embodiments of the present invention. It may be a bus-shaped structure or a star-shaped structure, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0127] The communication unit 1103 is used to establish a communication channel, enabling the vehicle to communicate with other devices. It can receive user data sent by other devices or send user data to other devices.

[0128] The processor 1101 serves as the vehicle's control center, connecting various parts of the vehicle via various interfaces and lines. It executes software programs, instructions, and / or modules stored in the memory 1102, and calls data stored in the memory to perform various vehicle functions and / or process data. The processor can be composed of integrated circuits (ICs), such as a single packaged IC or multiple packaged ICs with the same or different functions connected together. For example, the processor 1101 may consist only of a central processing unit (CPU). In this embodiment of the invention, the CPU may have a single processing core or include multiple processing cores.

[0129] The memory 1102 is used to store the execution instructions of the processor 1101. The memory 1102 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0130] When the execution instructions in memory 1102 are executed by processor 1101, the vehicle 1100 is able to perform its functions. Figure 2 , Figure 6 , Figure 8 or Figure 9 Some or all of the steps in the illustrated embodiments.

[0131] In a specific implementation, this application also provides a computer storage medium, wherein the computer storage medium may store a program, which, when executed, may include some or all of the steps of the steering control method provided in various embodiments of this application. The storage medium may be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0132] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0133] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0134] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0135] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0136] The same or similar parts between the various embodiments in this specification can be referred to mutually. In particular, the device embodiments and terminal embodiments are basically similar to the method embodiments, so the description is relatively simple, and the relevant parts can be referred to the description in the method embodiments.

Claims

1. A steering control method, characterized in that, Applied to a vehicle, the vehicle including a power steering motor, the method includes: The actual wheel angle, longitudinal acceleration, and yaw rate of the vehicle are obtained. Based on the longitudinal acceleration and the yaw rate, the target wheel angle is determined using a yaw dynamics model, wherein the yaw dynamics model takes the yaw rate approaching zero as the control objective. The steering assist motor is driven to reduce the deviation between the actual wheel angle and the target wheel angle.

2. The method according to claim 1, characterized in that, The vehicle includes wheel angle sensors for detecting angular displacement between the kingpin and the steering knuckle; The process of obtaining the actual wheel angle of the vehicle includes: The actual wheel angle of the vehicle is determined based on the angular displacement between the kingpin and the steering knuckle.

3. The method according to claim 1, characterized in that, The step of driving the power steering motor based on the deviation between the actual wheel angle and the target wheel angle includes: The gain coefficient of the PID control algorithm is adjusted according to the vehicle speed and / or the longitudinal acceleration. The deviation between the actual wheel angle and the target wheel angle is input into the PID control algorithm after the gain coefficient is adjusted to determine the motor drive signal; The motor drive signal is output to the power steering motor to drive the power steering motor.

4. The method according to claim 1, characterized in that, The yaw dynamics model includes the yaw moment balance equation: ； Where a is the distance from the center of mass to the front axle, k1 is the steering wheel lateral stiffness, δ is the wheel angle, m is the vehicle mass, α is the longitudinal acceleration, and I z The moment of inertia of the vehicle's yaw motion. This is the yaw acceleration.

5. The method according to claim 4, characterized in that, Before determining the target wheel angle based on the yaw dynamics model, the process also includes: Obtain the vehicle's load information and suspension height information; Based on the load information and the suspension height information, determine the vehicle mass and / or steering wheel lateral stiffness in the yaw moment balance equation.

6. The method according to claim 1, characterized in that, The step of driving the power steering motor based on the deviation between the actual wheel angle and the target wheel angle includes: Get the steering wheel angle and steering wheel torque; Based on the steering wheel angle and the steering wheel torque, determine whether the driver has a steering intention; When it is determined that the driver has no intention to steer, the steering assist motor is driven according to the deviation between the actual wheel angle and the target wheel angle.

7. The method according to claim 6, characterized in that, The determination of whether the driver intends to turn includes: When the absolute value of the steering wheel angle is less than or equal to the angle threshold and the absolute value of the steering wheel torque is less than or equal to the torque threshold, it is determined that the driver has no intention to steer. When the absolute value of the steering wheel angle is greater than the angle threshold or the absolute value of the steering wheel torque is greater than the torque threshold, it is determined that the driver has a steering intention.

8. A steering control method, characterized in that, Applied to a vehicle, the vehicle including a power steering motor, the method includes: Obtain the actual wheel angle, lane line information, and vehicle speed of the vehicle; Based on the lane line information, determine the lateral deviation of the vehicle relative to the lane line; The target wheel angle is determined based on the lateral deviation and the vehicle speed; The steering assist motor is driven to reduce the deviation between the actual wheel angle and the target wheel angle.

9. The method according to claim 8, characterized in that, Determining the target wheel angle based on the lateral deviation and the vehicle speed includes: Based on the lateral deviation and the vehicle speed, determine the desired vehicle yaw rate; Obtain the longitudinal acceleration of the vehicle; The target wheel rotation angle is calculated using a yaw dynamics model based on the desired yaw rate and the longitudinal acceleration.

10. A steering control device, characterized in that, include: The information acquisition module is used to acquire the actual wheel angle of the vehicle, the longitudinal acceleration of the vehicle, and the yaw rate of the vehicle. The target wheel rotation angle determination module is used to determine the target wheel rotation angle based on the longitudinal acceleration and the yaw rate, according to a yaw dynamics model, wherein the yaw dynamics model takes the yaw rate approaching zero as the control target; The power steering motor drive module is used to drive the power steering motor to reduce the deviation between the actual wheel angle and the target wheel angle.

11. A vehicle, characterized in that, include: processor; Memory; And a computer program, wherein the computer program is stored in the memory, the computer program including instructions that, when executed by the processor, cause the vehicle to perform the method of any one of claims 1 to 9.

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