Steering control method, device, equipment and medium of vehicle

Abstract

The application discloses a kind of steering control method, device, equipment and medium of vehicle.The method comprises: determining the current state of each steering controller of vehicle, and determining the vehicle steering state equation matched with the current state of each steering controller;The vehicle steering state equation matched with the current state of each steering controller is solved, and at least three expected steering angle values of wheel are obtained;According to each expected steering angle value, the steering control is carried out to vehicle.The method matches different control methods according to the state of different steering controllers, can realize different control strategies according to different fault states, realize the control to vehicle, ensure the safe driving of vehicle when fault occurs.

Description

Technical Field

[0001] This invention relates to the field of autonomous driving control technology, and in particular to a vehicle steering control method, device, equipment, and medium. Background Technology

[0002] Autonomous driving technology is already widely used in the passenger vehicle sector, but currently it is mainly applied to front-wheel steering vehicles, where the left and right wheels are mechanically connected and there is no rear-wheel steering. Most current autonomous driving algorithms are designed for vehicles with a front-wheel steering configuration. Rear-wheel steering is gradually becoming more common, and the development of drive-by-wire chassis is gaining momentum. Existing autonomous driving control algorithms are not yet compatible with rear-wheel steering and four-wheel independent steering vehicles. Summary of the Invention

[0003] This invention provides a vehicle steering control method, device, equipment, and medium to control the vehicle by employing different control strategies based on different fault states when the vehicle steering controller malfunctions.

[0004] In a first aspect, embodiments of the present invention provide a vehicle steering control method, the method comprising:

[0005] Determine the current state of each steering controller of the vehicle, and determine the vehicle steering state equation that matches the current state of each steering controller.

[0006] Solve the vehicle steering state equations that match the current state of each steering controller to obtain the desired steering angle values ​​for at least three wheels;

[0007] The vehicle is steered according to the desired turning angle values.

[0008] Secondly, embodiments of the present invention also provide a vehicle steering control device, the device comprising:

[0009] The state equation determination module is used to determine the current state of each steering controller of the vehicle and to determine the vehicle steering state equation that matches the current state of each steering controller.

[0010] The desired steering angle determination module is used to solve the vehicle steering state equation that matches the current state of each steering controller to obtain the desired steering angle values ​​of at least three wheels.

[0011] The control module is used to control the vehicle's steering based on the desired steering angle values.

[0012] Thirdly, embodiments of the present invention also provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement a vehicle steering control method as described in any of the embodiments of the present invention.

[0013] Fourthly, embodiments of the present invention also provide a storage medium for storing computer-executable instructions, which, when executed by a computer processor, are used to perform a vehicle steering control method as described in any of the embodiments of the present invention.

[0014] The technical solution of this invention determines the matching vehicle steering state equation based on the current state of each steering controller, solves the obtained vehicle steering state equation to obtain the desired wheel steering angle, and controls the vehicle based on the desired wheel steering angle. This method matches different control methods according to the state of different steering controllers, enabling the adoption of different control strategies based on different fault states, thereby controlling the vehicle and ensuring safe driving when a fault occurs.

[0015] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart of a vehicle steering control method provided in Embodiment 1 of the present invention;

[0018] Figure 2 A flowchart of another vehicle steering control method provided in Embodiment 2 of the present invention;

[0019] Figure 3 A flowchart of another vehicle steering control method provided in Embodiment 3 of the present invention;

[0020] Figure 4 This is a schematic diagram of the structure of a vehicle steering control device provided in Embodiment 4 of the present invention;

[0021] Figure 5 This is a schematic diagram of the structure of an electronic device provided in Embodiment 5 of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] Example 1

[0025] Figure 1 This is a flowchart of a vehicle steering control method provided in Embodiment 1 of the present invention. This embodiment can be applied to situations where different control strategies are determined according to different wheel fault conditions to achieve vehicle control. This method can be executed by a vehicle steering control device, which can be implemented in hardware and / or software. The vehicle steering control device can be configured in an electronic device with network connectivity.

[0026] like Figure 1 As shown, the method includes:

[0027] S110. Determine the current state of each steering controller of the vehicle, and determine the vehicle steering state equation that matches the current state of each steering controller.

[0028] A steering controller can be a device that assists a vehicle in steering. This embodiment applies to vehicles with independent steering, where there is a one-to-one correspondence between the steering controller and the wheels, with one steering controller controlling the rotation of one wheel. The steering controller used in this embodiment for an independent steering vehicle includes a redundancy mechanism; that is, the steering controller and its redundant system jointly control the rotation of one wheel. When the steering controller fails, the redundant system takes over control of the wheel. When both the steering controller and its redundant system fail simultaneously, the steering of the wheel corresponding to that steering controller fails.

[0029] The current state of the steering controller is the steering controller working state and the dual-level fault state. The steering controller working state includes: the state in which all steering controllers can work normally and at least one single-level fault state. The state in which all steering controllers can work normally means that the steering controllers of each wheel can achieve wheel steering; the single-level fault state means that the steering controller of a single wheel fails, but the redundant system of the steering controller can control the wheel to rotate; the dual-level fault state means that the steering controller of a single wheel and the redundant system of the steering controller both fail, and the steering controller can no longer control the wheel to complete steering.

[0030] Based on the current state of each steering controller received by the Electronic Control Unit (ECU), the vehicle steering state equation matching the current state of each steering controller is determined.

[0031] S120. Solve the vehicle steering state equations that match the current states of each steering controller to obtain the desired steering angle values ​​for at least three wheels.

[0032] The desired steering angle can be the steering angle value of the wheel that is expected to rotate, obtained by solving the vehicle steering state equation.

[0033] The vehicle steering state equation can be a dynamic model established based on the relationships between various vehicle parameters. Different vehicle steering states correspond to different vehicle steering state equations. For example, when the vehicle is a four-wheeled vehicle, the working state corresponds to the four-wheel vehicle steering state equation; the two-level fault state corresponds to the three-wheel vehicle steering state equation.

[0034] Solve the vehicle steering state equations matched with the current states of each steering controller to obtain the expected steering angle values ​​for at least three wheels.

[0035] It is understood that the technical solution of this embodiment supports vehicle steering angle control under dual-layer failure of one wheel. When dual-layer failure occurs in the steering controllers of two or more wheels, other methods are used for vehicle control, such as emergency braking, and this embodiment does not limit this.

[0036] S130. Perform steering control on the vehicle based on the desired steering angle values.

[0037] Based on the desired steering angle values ​​of each wheel obtained from the solution, the vehicle is steering controlled.

[0038] The technical solution of this invention determines the matching vehicle steering state equation based on the current state of each steering controller, solves the obtained vehicle steering state equation to obtain the desired wheel steering angle, and controls the vehicle based on the desired wheel steering angle. This method matches different control methods according to the state of different steering controllers, enabling the adoption of different control strategies based on different fault states, thereby controlling the vehicle and ensuring safe driving when a fault occurs.

[0039] Example 2

[0040] Figure 2 This is a flowchart of another vehicle steering control method provided in Embodiment 2 of the present invention. Based on the above embodiments, the present invention further specifies and determines the vehicle steering state equation that matches the current state of each steering controller.

[0041] like Figure 2 As shown, the method includes:

[0042] S210. Determine the current state of each steering controller of the vehicle. If the current state of each steering controller is determined to be a working state, determine the vehicle steering state equation that matches the working state of each steering controller.

[0043] The operating status of each steering controller can be either that all steering controllers are working normally or that at least one steering controller is in a single-level fault state.

[0044] The current state of each steering controller received by the Electronic Control Unit (ECU) is determined. If the current state of each steering controller is a working state, that is, each steering controller can work normally or at least one single-layer fault state, the vehicle steering state equation matching the working state of each steering controller is determined.

[0045] Optionally, determine the vehicle steering state equations that match the operating states of each steering controller, including:

[0046] The vehicle steering state equation, which matches the operating states of each steering controller, is expressed by the following equation:

[0047]

[0048] Among them, e y Indicates lateral positional deviation. The first derivative representing the lateral positional deviation. This is the lateral angular deviation. C is the first derivative of the lateral angular deviation. flC represents the lateral stiffness of the vehicle's left front wheel, where lateral stiffness is a parameter of the vehicle's tires and can be obtained from the vehicle's manufacturer's specifications. fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, C rr V represents the lateral stiffness of the right rear wheel of the vehicle, m represents the vehicle mass, and V represents the lateral stiffness. x For the longitudinal speed of the vehicle, l f l is the distance from the vehicle's center of gravity to the front axle. r I is the distance from the vehicle's center of gravity to the rear axle. z Let δ be the moment of inertia of the vehicle about the z-axis. fl Let δ be the steering angle of the left front wheel, where the wheel steering angle is the angle between the longitudinal plane of the wheel and the x-axis of the vehicle. fr The steering angle of the right front wheel is δ. rl The left rear wheel steering angle is δ. rr For the right rear wheel steering angle, Let be the first derivative of the desired heading angle.

[0049] Furthermore, the process of determining the above equations includes:

[0050] First, establish the vehicle's dynamic model:

[0051]

[0052]

[0053] The X-axis points in the direction of vehicle movement, the y-axis points to the left in the direction of movement, and the z-axis is vertical. Indicates the lateral acceleration of the vehicle. The second derivative represents the change in the vehicle's longitudinal position. The first derivative represents the change in the vehicle's longitudinal position. The first derivative represents the change in the vehicle's heading angle, where m is the vehicle's mass and l is the vehicle's mass. f l is the distance from the vehicle's center of gravity to the front axle. r I is the distance from the vehicle's center of gravity to the rear axle. z Let F be the moment of inertia of the vehicle about the z-axis. yfl The lateral force F is the force on the left front wheel. yfr F is the lateral force on the right front wheel. yrl F is the lateral force on the left rear wheel. yrr This is the lateral force on the right rear wheel.

[0054] The lateral forces of each wheel are as follows:

[0055]

[0056]

[0057]

[0058]

[0059] Among them, C fl For the lateral stiffness of the vehicle's left front wheel, C fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, C rr δ represents the lateral stiffness of the right rear wheel of the vehicle. fl The left front wheel steering angle is δ. fr The steering angle of the right front wheel is δ. rl The left rear wheel steering angle is δ. rr For the right rear wheel steering angle, The first derivative represents the change in the vehicle's heading angle. The lateral velocity is the first derivative of the vehicle's lateral displacement.

[0060] The path tracking deviation equation is established based on the vehicle's dynamic model, as follows:

[0061]

[0062]

[0063] Among them, e y To track lateral position deviation during the process, where lateral deviation is the lateral deviation of the vehicle's position relative to the desired trajectory, the point on the desired trajectory that is closest to the vehicle's position is found; the distance between this closest point and the vehicle's position is the lateral deviation. The second derivative of the lateral deviation in path tracking. The first derivative of the lateral deviation in path tracking. For path tracking, the lateral angle deviation is defined as follows: The deviation can be the heading angle deviation, which is the angular deviation of the vehicle's heading relative to the desired trajectory. The heading angle deviation is the difference between the desired heading and the vehicle's heading at the point on the desired trajectory that is closest to the vehicle's position. The first derivative of the lateral angle deviation for path tracking. Let yaw rate be the first derivative of the desired heading angle, i.e., the desired yaw rate. The desired heading angle is not a fixed value; it is affected by vehicle movement. Changes in the point on the desired trajectory closest to the vehicle's position will change the desired heading angle. The second derivative of the lateral angle deviation for path tracking. Let be the second derivative of the desired heading angle.

[0064] By rearranging the path tracking deviation equation, the vehicle steering state equation matching the working state of each steering controller can be obtained.

[0065] S220. Based on the improved linear quadratic regulator algorithm, determine the feedback control equation that matches the vehicle steering state equation.

[0066] The Linear Quadratic Regulator (LQR) algorithm is a commonly used method for solving linear quadratic problems. It uses a designed state feedback controller K to minimize the quadratic objective function J.

[0067] Based on the improved LQR algorithm and the vehicle steering state equation, a feedback control equation that matches the vehicle steering state equation is derived.

[0068] Furthermore, the vehicle steering state equation is transformed into the following form:

[0069]

[0070] Among them, the state variables are A and B are coefficient matrices.

[0071] S230. Solve the feedback control equations using dynamic programming to obtain the feedback steering angle values ​​for each wheel.

[0072] Dynamic programming is a method used in mathematics, computer science, and economics to solve complex problems by breaking them down into relatively simpler subproblems.

[0073] By dynamically solving the above control equations, feedback steering angle values ​​for at least three wheels are obtained.

[0074] Optionally, the feedback control equations can be solved using dynamic programming, including:

[0075] Determine the state variable weight matrix and the control variable weight matrix, and solve the feedback control equation by dynamic programming based on the state variable weight matrix and the control variable weight matrix.

[0076] The weight matrices of the state variables and the control variables are determined based on the magnitudes of the lateral deviation and the lateral angular deviation, as well as the feedback control equations.

[0077] Furthermore, the trial-and-error method is used to determine the state variable weight matrix and the control variable weight matrix. The trial-and-error method can be a method of tuning parameters based on experience. In the closed-loop control system, the magnitude of the lateral deviation and the magnitude of the lateral angle deviation are adjusted. While adjusting the parameters, the control process is observed until the requirements are met.

[0078] By adjusting the lateral deviation and lateral angular deviation according to the above steps, the resulting state variable weight matrix and control variable weight matrix can satisfy most operating conditions.

[0079] The state weight matrix is ​​represented by the following formula: q4 = 0, e y-max This indicates the maximum lateral positional deviation. q represents the maximum lateral angular deviation. 1init q is the initial value of the weight of the lateral position deviation state variable. 3init This represents the initial value of the weight of the lateral angle deviation state variable.

[0080] The control weight matrix is ​​represented by the following formula:

[0081] Where r1, r2, r3, and r4 represent the steering angle control weights of each steering controller, r1 init r2 init r3 init r4 init These represent the initial values ​​of the steering angle control weights for each steering controller.

[0082] Furthermore, the feedback control equations are solved dynamically to obtain the feedback rotation angle value U. fb for:

[0083]

[0084]

[0085] in,

[0086]

[0087]

[0088] The above steps, which use feedback control to determine the vehicle's steering angle, can maintain system stability by continuously adjusting the input signal and have a certain degree of anti-interference capability when facing external disturbances and changes. By comparing the actual output with the expected output in real time, feedback control can enable the system to achieve the expected goal more accurately.

[0089] Optionally, after obtaining the feedback steering angle values ​​for each wheel, steps A1-A3 are also included:

[0090] Step A1: Determine the steady-state tracking equation that matches the feedback control equation.

[0091] The steady-state tracking equation can be determined by the following formula:

[0092] X(s) = [SI - (A - BK)] -1+BL(U)+L(M)

[0093] Where X is A and B are coefficient matrices.

[0094] Step A2: Solve the steady-state tracking equation to obtain the feedforward steering angle value of each wheel.

[0095] Let the steady-state tracking deviation of the state variable be e y If the value is 0, the feedforward rotation angle U can be obtained by solving the steady-state tracking equation. ff .

[0096] Step A3: Add the feedback steering angle value and the feedforward steering angle value of each wheel to obtain the desired steering angle value that matches each wheel.

[0097] The obtained feedback steering angle value U of each wheel fb and feedforward rotation angle value U ff The summation yields the expected steering angle value u for each wheel. t , that is u t =U fb +U ff .

[0098] By adopting the above steps, the feedforward control can make the steady-state tracking deviation of the state variables zero.

[0099] S240. Steering control of the vehicle is performed based on the desired steering angle values.

[0100] Based on the obtained desired turning angles, the vehicle is steered.

[0101] In this embodiment, when the target steering controller is in a normal state or a single-layer fault state, the corresponding feedback control equation is determined, the feedback control equation is solved to obtain the feedback steering angle value, and feedforward control is introduced on the basis of feedback control to obtain the feedforward steering angle value, thereby obtaining the desired steering angle value of the vehicle. The vehicle is controlled according to the desired steering angle value, which enables the vehicle to be controlled by the corresponding control strategy when it is in a normal state or a single-layer fault state, thus ensuring the normal driving of the vehicle.

[0102] Example 3

[0103] Figure 3 This is a flowchart of another vehicle steering control method provided in Embodiment 3 of the present invention. Based on the above embodiments, the present invention further specifies and determines the vehicle steering state equation that matches the current state of each steering controller.

[0104] like Figure 3 As shown, the method includes:

[0105] S310. Determine the current state of each steering controller of the vehicle. If the current state of the target steering controller is determined to be a double-layer fault state, then determine the vehicle steering state equation that matches the double-layer fault state of the target steering controller.

[0106] The target steering controller can be a steering controller in a dual-fault state.

[0107] The current state of each steering controller received by the electronic controller unit is determined. If the target steering controller is in a double-layer fault state, that is, the steering controllers of all wheels are in a fault state, then the vehicle steering state equation that matches it is determined.

[0108] Optionally, determine the vehicle steering state equation that matches the two-layer fault state of the target steering controller, including:

[0109] The vehicle steering state equation, which matches the two-layer fault state of the target steering controller, is expressed by the following formula:

[0110]

[0111] Among them, e y Indicates lateral positional deviation. The first derivative representing the lateral positional deviation. This is the lateral angular deviation. C is the first derivative of the lateral angular deviation. fl For the lateral stiffness of the vehicle's left front wheel, C fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, C rr For the lateral stiffness of the right rear wheel of the vehicle, l f l is the distance from the vehicle's center of gravity to the front axle. r Let C1 be the distance from the vehicle's center of gravity to the rear axle, C2-C4 be the wheel lateral stiffness corresponding to the target steering controller, δ1 be the target wheel's steering angle corresponding to the target steering controller, δ2-δ4 be the wheel's steering angles corresponding to the other steering controllers besides the target wheel, l1 / l2 / l3 / l4 represent the distance from the vehicle's center of gravity to the target axle (either the front or rear axle), and m be the vehicle's mass. Let V be the distance from the vehicle's center of gravity to the target axle. x For the longitudinal speed of the vehicle, I z Let be the moment of inertia of the vehicle about the z-axis. Let be the first derivative of the desired heading angle.

[0112] For example, when the target steering controller has a dual-layer fault state, specifically a dual-layer fault state of the left front wheel steering controller, the left front wheel steering angle is considered to be a fixed value. The control variables become the right front wheel steering angle, the left rear wheel steering angle, and the right rear wheel steering angle. The vehicle steering state equation is as follows:

[0113]

[0114] Among them, e y Indicates lateral positional deviation. The first derivative representing the lateral positional deviation. This is the lateral angular deviation. C is the first derivative of the lateral angular deviation. fl For the lateral stiffness of the vehicle's left front wheel, C fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, C rr For the lateral stiffness of the right rear wheel of the vehicle, l f l is the distance from the vehicle's center of gravity to the front axle. r I is the distance from the vehicle's center of gravity to the rear axle. z Let δ be the moment of inertia of the vehicle about the z-axis. fl The left front wheel steering angle is δ. fr The steering angle of the right front wheel is δ. rl The left rear wheel steering angle is δ. rr For the right rear wheel steering angle, Let be the first derivative of the desired heading angle.

[0115] For example, when the target steering controller has a dual-layer fault state, specifically a dual-layer fault state of the right front wheel, the right front wheel steering angle is considered to be a fixed value. The control variables become the left front wheel steering angle, the left rear wheel steering angle, and the right rear wheel steering angle. The vehicle steering state equation is as follows:

[0116]

[0117] Among them, e y Indicates lateral positional deviation. The first derivative representing the lateral positional deviation. This is the lateral angular deviation. C is the first derivative of the lateral angular deviation. fl For the lateral stiffness of the vehicle's left front wheel, C fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, C rr For the lateral stiffness of the right rear wheel of the vehicle, l f l is the distance from the vehicle's center of gravity to the front axle. r I is the distance from the vehicle's center of gravity to the rear axle. z Let δ be the moment of inertia of the vehicle about the z-axis. fl The left front wheel steering angle is δ. frThe steering angle of the right front wheel is δ. rl The left rear wheel steering angle is δ. rr For the right rear wheel steering angle, Let be the first derivative of the desired heading angle.

[0118] For example, when the target steering controller has a dual-layer fault state, specifically a left rear wheel dual-layer fault state, the left rear wheel steering angle is considered a fixed value. The control variables become the left front wheel steering angle, right front wheel steering angle, and right rear wheel steering angle. The vehicle steering state equation is as follows:

[0119]

[0120] Among them, e y Indicates lateral positional deviation. The first derivative representing the lateral positional deviation. This is the lateral angular deviation. C is the first derivative of the lateral angular deviation. fl For the lateral stiffness of the vehicle's left front wheel, C fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, C rr For the lateral stiffness of the right rear wheel of the vehicle, l f l is the distance from the vehicle's center of gravity to the front axle. r I is the distance from the vehicle's center of gravity to the rear axle. z Let δ be the moment of inertia of the vehicle about the z-axis. fl The left front wheel steering angle is δ. fr The steering angle of the right front wheel is δ. rl The left rear wheel steering angle is δ. rr For the right rear wheel steering angle, Let be the first derivative of the desired heading angle.

[0121] For example, in the dual-layer fault state of the target steering controller, after a fault in the right rear wheel steering system, the right rear wheel angle is a fixed value, and the control variables become the left front wheel angle, right front wheel angle, and left rear wheel angle. The vehicle steering state equation is as follows:

[0122]

[0123]

[0124] Among them, e y Indicates lateral positional deviation. The first derivative representing the lateral positional deviation. This is the lateral angular deviation. C is the first derivative of the lateral angular deviation. fl For the lateral stiffness of the vehicle's left front wheel, C fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, Crr For the lateral stiffness of the right rear wheel of the vehicle, l f l is the distance from the vehicle's center of gravity to the front axle. r I is the distance from the vehicle's center of gravity to the rear axle. z Let δ be the moment of inertia of the vehicle about the z-axis. fl The left front wheel steering angle is δ. fr The steering angle of the right front wheel is δ. rl The left rear wheel steering angle is δ. rr For the right rear wheel steering angle, Let be the first derivative of the desired heading angle.

[0125] S320. Based on the improved linear quadratic regulator algorithm, determine the feedback control equation that matches the vehicle steering state equation.

[0126] Based on the improved LQR algorithm and the vehicle steering state equation, a feedback control equation that matches the vehicle steering state equation is derived.

[0127] Furthermore, the vehicle steering state equation is transformed into the following form:

[0128]

[0129] Among them, the state variables are A and B are coefficient matrices.

[0130] S330. Solve the feedback control equations using dynamic programming to obtain the feedback steering angle values ​​for at least three wheels.

[0131] By dynamically solving the above control equations, feedback steering angle values ​​for at least three wheels are obtained.

[0132] Optionally, the feedback control equations can be solved using dynamic programming, including:

[0133] Determine the state variable weight matrix and the control variable weight matrix, and solve the feedback control equation by dynamic programming based on the state variable weight matrix and the control variable weight matrix.

[0134] The weight matrices of the state variables and the control variables are determined based on the magnitudes of the lateral deviation and the lateral angular deviation, as well as the feedback control equations.

[0135] The state weight matrix is ​​represented by the following formula: q4 = 0, e y-max This indicates the maximum lateral positional deviation. q represents the maximum lateral angular deviation. 1init q is the initial value of the weight of the lateral position deviation state variable. 3init This represents the initial value of the weight of the lateral angle deviation state variable.

[0136] If the current state of the target steering controller is a two-level fault state, then the control quantity weight matrix is ​​represented by the following formula: Where r1, r2, and r3 represent the steering angle control weights of steering controllers other than the target steering controller, r1 init r2 init r3 init This represents the initial weight of the steering angle control quantity for steering controllers other than the target steering controller.

[0137] Furthermore, the feedback control equations are solved dynamically to obtain the feedback rotation angle value U. fb for:

[0138]

[0139]

[0140] in,

[0141]

[0142]

[0143] The above steps, which use feedback control to determine the vehicle's steering angle, can maintain system stability by continuously adjusting the input signal and have a certain degree of anti-interference capability when facing external disturbances and changes. By comparing the actual output with the expected output in real time, feedback control can enable the system to achieve the expected goal more accurately.

[0144] Optionally, after obtaining the feedback steering angle values ​​from at least three wheels, steps B1-B3 are also included:

[0145] Step B1: Determine the steady-state tracking equation that matches the feedback control equation.

[0146] The steady-state tracking equation can be determined by the following formula:

[0147] X(s) = [SI - (A - BK)] -1 +BL(U)+L(M)

[0148] Where X is A and B are coefficient matrices.

[0149] Step B2: Solve the steady-state tracking equation to obtain the feedforward steering angle values ​​for at least three wheels.

[0150] Let the steady-state tracking deviation of the state variable be e y If the value is 0, the feedforward rotation angle U can be obtained by solving the steady-state tracking equation. ff .

[0151] Step B3: Add the feedback steering angle value and the feedforward steering angle value of each wheel to obtain the desired steering angle value that matches each wheel.

[0152] The obtained feedback steering angle value U of each wheel fb and feedforward rotation angle value U ff The summation yields the expected steering angle value u for each wheel. t , that is u t =U fb +U ff .

[0153] By adopting the above steps, the feedforward control can make the steady-state tracking deviation of the state variables zero.

[0154] S340. Steering control of the vehicle is performed based on the desired steering angle values.

[0155] Based on the obtained desired turning angles, the vehicle is steered.

[0156] In this embodiment, when the target steering controller is in a dual-fault state, the feedback control equation matching the dual-fault state is determined, the feedback control equation is solved to obtain the feedback steering angle value, and feedforward control is introduced on the basis of feedback control to obtain the feedforward steering angle value, thereby obtaining the desired steering angle value of the vehicle. The vehicle is controlled according to the desired steering angle value, which enables the use of a corresponding control strategy when the vehicle experiences a dual-fault, thus ensuring the normal driving of the vehicle.

[0157] In embodiments of the present invention, when a single wheel experiences a single-layer fault or is driving normally, the desired steering angles of the four wheels are obtained by solving the independent steering state equations of the four wheels and the improved LQR method. When a single wheel experiences a double-layer fault, the faulty wheel's steering angle is fixed and it cannot rotate normally. The desired steering angles of the three wheels are obtained by solving the independent steering state equations of the three wheels and the improved LQR method. The method of the present invention can determine different control strategies based on different steering controller states, ensuring safe driving of the vehicle.

[0158] Example 4

[0159] Figure 4 This is a schematic diagram of a vehicle steering control device provided in Embodiment 4 of the present invention. Figure 4 As shown, the device includes:

[0160] State equation determination module 410: used to determine the current state of each steering controller of the vehicle and to determine the vehicle steering state equation that matches the current state of each steering controller.

[0161] Desired steering angle determination module 420: used to solve the vehicle steering state equation that matches the current state of each steering controller to obtain the desired steering angle values ​​of at least three wheels;

[0162] Control module 430: Used to control the vehicle's steering based on the desired steering angle values.

[0163] Optionally, the state equation determination module 410 includes:

[0164] Two-level fault state equation determination unit: used to determine the vehicle steering state equation that matches the two-level fault state of the target steering controller if the current state of the target steering controller is determined to be a two-level fault state.

[0165] State equation determination unit: otherwise, determines the vehicle steering state equation that matches the operating state of each steering controller.

[0166] Optionally, a two-level fault state equation determination element is used specifically for:

[0167] The vehicle steering state equation, which matches the two-layer fault state of the target steering controller, is expressed by the following formula:

[0168]

[0169]

[0170] Among them, e y Indicates lateral positional deviation. The first derivative representing the lateral positional deviation. This is the lateral angular deviation. C is the first derivative of the lateral angular deviation. fl For the lateral stiffness of the vehicle's left front wheel, C fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, C rr For the lateral stiffness of the right rear wheel of the vehicle, l f l is the distance from the vehicle's center of gravity to the front axle. r Let C1 be the distance from the vehicle's center of gravity to the rear axle, C2-C4 be the wheel lateral stiffness corresponding to the target steering controller, δ1 be the target wheel's steering angle corresponding to the target steering controller, δ2-δ4 be the wheel's steering angles corresponding to the other steering controllers besides the target wheel, l1 / l2 / l3 / l4 represent the distance from the vehicle's center of gravity to the target axle (either the front or rear axle), and m be the vehicle's mass. Let V be the distance from the vehicle's center of gravity to the target axle. x For the longitudinal speed of the vehicle, I z Let be the moment of inertia of the vehicle about the z-axis. Let be the first derivative of the desired heading angle.

[0171] Optional, state equations determine the unit, specifically used for:

[0172] The vehicle steering state equation, which matches the operating states of each steering controller, is expressed by the following equation:

[0173]

[0174] Among them, e y Indicates lateral positional deviation. The first derivative representing the lateral positional deviation. This is the lateral angular deviation. C is the first derivative of the lateral angular deviation. fl For the lateral stiffness of the vehicle's left front wheel, C fr C represents the lateral stiffness of the vehicle's right front wheel. rl For the lateral stiffness of the vehicle's left rear wheel, C rr V represents the lateral stiffness of the right rear wheel of the vehicle, m represents the vehicle mass, and V represents the lateral stiffness. x For the longitudinal speed of the vehicle, l f l is the distance from the vehicle's center of gravity to the front axle. r I is the distance from the vehicle's center of gravity to the rear axle. z Let δ be the moment of inertia of the vehicle about the z-axis. fl The left front wheel steering angle is δ. fr The steering angle of the right front wheel is δ. rl The left rear wheel steering angle is δ. rr For the right rear wheel steering angle, Let be the first derivative of the desired heading angle.

[0175] Optionally, the desired angle value determination module 420 includes:

[0176] Feedback control equation determination unit: used to determine the feedback control equation that matches the vehicle steering state equation based on the improved linear quadratic regulator algorithm;

[0177] Feedback steering angle determination unit: used to perform dynamic programming to solve the feedback control equation and obtain the feedback steering angle values ​​of at least three wheels.

[0178] Optionally, the desired angle value determination module 420 also includes:

[0179] Steady-state tracking equation determination unit: used to determine the steady-state tracking equation that matches the feedback control equation;

[0180] Feedforward steering angle determination unit: used to solve the steady-state tracking equation to obtain the feedforward steering angle values ​​of at least three wheels;

[0181] Desired steering angle determination unit: used to add the feedback steering angle value and feedforward steering angle value of each wheel to obtain the desired steering angle value that matches each wheel.

[0182] Optional, a feedback angle value determination unit, specifically used for:

[0183] Determine the state variable weight matrix and the control variable weight matrix, and solve the feedback control equation by dynamic programming based on the state variable weight matrix and the control variable weight matrix.

[0184] The state weight matrix is ​​represented by the following formula: q4 = 0, e y-max This indicates the maximum lateral positional deviation. q represents the maximum lateral angular deviation. 1init q is the initial value of the weight of the lateral position deviation state variable. 3init This represents the initial value of the weight of the lateral angle deviation state quantity;

[0185] If the current state of the target steering controller is determined to be a two-level fault state, then the control quantity weight matrix is ​​represented by the following formula: Where r1, r2, and r3 represent the steering angle control weights of steering controllers other than the target steering controller, r1 init r2 init r3 init This represents the initial weight of the angle control quantity for steering controllers other than the target steering controller;

[0186] Otherwise, the control weight matrix is ​​represented by the following formula:

[0187] Where r1, r2, r3, and r4 represent the steering angle control weights of each steering controller, r1 init r2 init r3 init r4 init These represent the initial values ​​of the steering angle control weights for each steering controller.

[0188] The vehicle steering control device provided in the embodiments of the present invention can execute the vehicle steering control method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the method execution.

[0189] Example 5

[0190] Figure 5This is a schematic diagram of an electronic device provided in Embodiment 5 of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0191] like Figure 5 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 may also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0192] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0193] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as vehicle steering control methods.

[0194] In some embodiments, the vehicle steering control method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the vehicle steering control method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the vehicle steering control method by any other suitable means (e.g., by means of firmware).

[0195] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0196] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0197] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0198] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0199] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0200] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0201] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0202] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A vehicle steering control method, characterized in that, include: Determine the current state of each steering controller of the vehicle, and determine the vehicle steering state equation that matches the current state of each steering controller. Solve the vehicle steering state equations that match the current state of each steering controller to obtain the desired steering angle values ​​for at least three wheels; The vehicle is steered according to the desired turning angle values. The determination of the vehicle steering state equation that matches the current state of each steering controller includes: If the current state of the target steering controller is determined to be a two-level fault state, then the vehicle steering state equation that matches the two-level fault state of the target steering controller is determined. Otherwise, determine the vehicle steering state equation that matches the operating state of each steering controller; Among them, determining the vehicle steering state equation that matches the dual-layer fault state of the target steering controller includes: The vehicle steering state equation, which matches the two-layer fault state of the target steering controller, is expressed by the following formula: ； in, Indicates lateral positional deviation. The first derivative represents the lateral positional deviation. This is the lateral angular deviation. The first derivative of the lateral angular deviation. The lateral stiffness of the vehicle's left front wheel. The lateral stiffness of the vehicle's right front wheel. The lateral stiffness of the vehicle's left rear wheel. The right rear wheel lateral stiffness of the vehicle. The distance from the vehicle's center of gravity to the front axle. C1 represents the distance from the vehicle's center of gravity to the rear axle, C2 represents the wheel lateral stiffness corresponding to the target steering controller, and C2-C4 represent the wheel lateral stiffness corresponding to other steering controllers besides the target steering controller. It is the target wheel angle corresponding to the target steering controller. For the wheel angles of all wheels except the target wheel, This represents the distance from the vehicle's center of gravity to the target axis, which can be either the front or rear axle. The target axis depends on... The corresponding wheel positions are determined, m is the vehicle mass, and V is... x For the longitudinal speed of the vehicle, Let be the moment of inertia of the vehicle about the z-axis. Let be the first derivative of the desired heading angle.

2. The method according to claim 1, characterized in that, Determine the vehicle steering state equations that match the operating states of each steering controller, including: The vehicle steering state equation, which matches the operating states of each steering controller, is expressed by the following equation: ； in, Indicates lateral positional deviation. The first derivative represents the lateral positional deviation. This is the lateral angular deviation. The first derivative of the lateral angular deviation. The lateral stiffness of the vehicle's left front wheel. The lateral stiffness of the vehicle's right front wheel. The lateral stiffness of the vehicle's left rear wheel. V is the lateral stiffness of the right rear wheel of the vehicle, m is the mass of the vehicle, and V is the lateral stiffness. x For the longitudinal speed of the vehicle, The distance from the vehicle's center of gravity to the front axle. The distance from the vehicle's center of gravity to the rear axle. Let be the moment of inertia of the vehicle about the z-axis. The left front wheel turning angle, The right front wheel steering angle, For the left rear wheel steering angle, For the right rear wheel steering angle, Let be the first derivative of the desired heading angle.

3. The method according to claim 1, characterized in that, Solve the vehicle steering state equations that match the current states of each steering controller to obtain the desired steering angle values ​​for at least three wheels, including: Based on the improved linear quadratic regulator algorithm, a feedback control equation matching the vehicle steering state equation is determined. The feedback control equations are solved by dynamic programming to obtain the feedback steering angle values ​​for at least three wheels.

4. The method according to claim 3, characterized in that, After obtaining the feedback steering angle values ​​from at least three wheels, the following is also included: Determine the steady-state tracking equation that matches the feedback control equation; Solving the steady-state tracking equation yields the feedforward steering angle values ​​for at least three wheels; The feedback steering angle value and the feedforward steering angle value of each wheel are added together to obtain the desired steering angle value that matches each wheel.

5. The method according to claim 3, characterized in that, The dynamic programming solution to the feedback control equation includes: Determine the state variable weight matrix and the control variable weight matrix, and solve the feedback control equation by dynamic programming based on the state variable weight matrix and the control variable weight matrix. The state weight matrix is ​​represented by the following formula: , , , , , This indicates the maximum lateral positional deviation. This indicates the maximum lateral angular deviation. The initial values ​​for the weights of the lateral position deviation state variables are: This represents the initial value of the weight of the lateral angle deviation state quantity; If the current state of the target steering controller is determined to be a two-level fault state, then the control quantity weight matrix is ​​represented by the following formula: , , , ,in, , , This indicates the weights of the angle control values ​​for steering controllers other than the target steering controller. , , This represents the initial weight of the angle control quantity for steering controllers other than the target steering controller; Otherwise, the control weight matrix is ​​represented by the following formula: , , , , ,in, , , r4 and r4 represent the weights of the steering angle control values ​​for each steering controller. , , , These represent the initial values ​​of the steering angle control weights for each steering controller.

6. A vehicle steering control device, characterized in that, include: The state equation determination module is used to determine the current state of each steering controller of the vehicle and to determine the vehicle steering state equation that matches the current state of each steering controller. The desired steering angle determination module is used to solve the vehicle steering state equation that matches the current state of each steering controller to obtain the desired steering angle values ​​of at least three wheels. The control module is used to control the vehicle's steering based on the desired steering angle values; The state equation determination module includes: The dual-level fault state equation determination unit is used to determine the vehicle steering state equation that matches the dual-level fault state of the target steering controller if the current state of the target steering controller is determined to be a dual-level fault state. The state equation determination unit is used to determine the vehicle steering state equation that matches the operating state of each steering controller, otherwise. Specifically, the dual-layer fault state equation determination unit is used for: The vehicle steering state equation, which matches the two-layer fault state of the target steering controller, is expressed by the following formula: ； in, Indicates lateral positional deviation. The first derivative represents the lateral positional deviation. This is the lateral angular deviation. The first derivative of the lateral angular deviation. The lateral stiffness of the vehicle's left front wheel. The lateral stiffness of the vehicle's right front wheel. The lateral stiffness of the vehicle's left rear wheel. The right rear wheel lateral stiffness of the vehicle. The distance from the vehicle's center of gravity to the front axle. C1 represents the distance from the vehicle's center of gravity to the rear axle, C2 represents the wheel lateral stiffness corresponding to the target steering controller, and C2-C4 represent the wheel lateral stiffness corresponding to other steering controllers besides the target steering controller. It is the target wheel angle corresponding to the target steering controller. For the wheel angles of all wheels except the target wheel, This represents the distance from the vehicle's center of gravity to the target axis, which can be either the front or rear axle. The target axis depends on... The corresponding wheel positions are determined, m is the vehicle mass, and V is... x For the longitudinal speed of the vehicle, Let be the moment of inertia of the vehicle about the z-axis. Let be the first derivative of the desired heading angle.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the vehicle steering control method as described in any one of claims 1-5.

8. A storage medium for storing computer-executable instructions, characterized in that, The computer-executable instructions, when executed by a computer processor, are used to perform the vehicle steering control method as described in any one of claims 1-5.

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