Steering control method, device, apparatus and storage medium

Abstract

The application discloses a kind of steering control method, device, equipment and storage medium, belong to vehicle technical field.The method comprises: in the case where receiving the steering angle control signal of the front wheel of vehicle, the input angle corresponding to the steering angle control signal is obtained;According to input angle and the current speed of vehicle, the front wheel steering angle and rear wheel steering angle of vehicle are determined;According to the front wheel steering angle, the front wheel steering of vehicle is controlled, and according to the rear wheel steering angle, the rear wheel steering of vehicle is controlled.The application improves the response speed and sensitivity of vehicle four-wheel steering, improves the maneuverability of vehicle four-wheel steering under low-speed steering and the stability under high-speed steering, improves the steering performance of vehicle.

Description

Technical Field

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

[0002] Four-wheel steering (4WS) technology is currently one of the research focuses in the field of vehicle active safety control. Four-wheel steering technology can independently control the steering of the front and rear wheels of a vehicle, which is beneficial to improving the low-speed maneuverability and high-speed stability of the vehicle.

[0003] In related technologies, a fixed steering ratio is typically used to achieve four-wheel steering in vehicles. During this process, the vehicle determines the corresponding rear-wheel steering angle based on the driver's control of the front wheel steering angles, according to the fixed steering ratio. The rear wheels are then steered according to these determined rear-wheel steering angles to achieve four-wheel steering.

[0004] Using the above-mentioned fixed steering ratio to achieve four-wheel steering results in low steering sensitivity at low speeds and excessively high steering sensitivity at high speeds, which is not conducive to the driver's control of the vehicle and has the problem of poor steering performance. Summary of the Invention

[0005] This application provides a steering control method, apparatus, device, and storage medium, which can improve the steering performance of a vehicle. The technical solution is as follows:

[0006] According to one aspect of this application, a steering control method is provided, the method comprising:

[0007] Upon receiving a steering angle control signal for the front wheels of the vehicle, the input steering angle corresponding to the steering angle control signal is obtained;

[0008] Based on the input steering angle and the vehicle's current speed, determine the front wheel steering angle and the rear wheel steering angle of the vehicle;

[0009] The vehicle’s front wheel steering is controlled based on the front wheel steering angle, and the vehicle’s rear wheel steering is controlled based on the rear wheel steering angle.

[0010] According to one aspect of this application, a steering control device is provided, the device comprising:

[0011] The acquisition module is used to acquire the input steering angle corresponding to the steering angle control signal when a steering angle control signal for the front wheels of the vehicle is received.

[0012] The determining module is used to determine the front wheel steering angle and the rear wheel steering angle of the vehicle based on the input steering angle and the current vehicle speed;

[0013] A control module is used to control the front wheel steering of the vehicle according to the front wheel steering angle, and to control the rear wheel steering of the vehicle according to the rear wheel steering angle.

[0014] In an optional design, the determining module is used for:

[0015] Based on the input steering angle and the current vehicle speed, determine the expected value of the vehicle's center of gravity sideslip angle and the expected value of its yaw rate.

[0016] Obtain the actual sideslip angle and actual yaw rate of the vehicle.

[0017] The front wheel steering angle and the rear wheel steering angle are determined based on the algebraic sum of the first error and the second error.

[0018] Wherein, the first error is the error between the expected value of the centroid sideslip angle and the actual centroid sideslip angle, and the second error is the error between the expected value of the yaw rate and the actual yaw rate.

[0019] In an optional design, the determining module is used for:

[0020] Obtain the control model corresponding to the vehicle, wherein the control model is a transfer function related to the steering of the vehicle;

[0021] The front wheel steering angle and the rear wheel steering angle are determined by the control model based on the algebraic sum of the first error and the second error.

[0022] In an optional design, the determining module is used for:

[0023] The reference center of gravity sideslip angle and reference yaw rate are obtained based on the internal model corresponding to the vehicle. The internal model is determined based on the diagonal matrix of the whole vehicle model corresponding to the vehicle. The whole vehicle model is the actual dynamic model of the vehicle.

[0024] By inputting the target algebraic sum into the control model, the front wheel steering angle and the rear wheel steering angle are obtained;

[0025] The target algebraic sum is determined based on the algebraic sum of the reference centroid sideslip angle, the reference yaw rate, the first error, and the second error.

[0026] In an optional design, the determining module is used for:

[0027] Obtain a reference model corresponding to the vehicle, wherein the reference model is a simulated dynamic model of the vehicle;

[0028] Based on the input steering angle and the current vehicle speed, the expected value of the center of gravity sideslip angle and the expected value of the yaw rate are determined by the reference model.

[0029] In an optional design, the determining module is used for:

[0030] Obtain the two-degree-of-freedom model corresponding to the vehicle, wherein the two-degree-of-freedom model is a dynamic model related to the yaw motion and lateral motion of the vehicle;

[0031] The reference model is determined based on the two-degree-of-freedom model.

[0032] According to another aspect of the embodiments of this application, a computer device is provided, the computer device including: a processor and a memory, the memory storing at least a program; the processor is used to execute the at least a program in the memory to implement the above-described steering control method.

[0033] According to another aspect of the embodiments of this application, a computer-readable storage medium is provided, which stores at least one program that is loaded and executed by a processor to implement the above-described steering control method.

[0034] According to another aspect of the embodiments of this application, a computer program product or computer program is provided, which includes computer instructions stored in a computer-readable storage medium, a processor obtaining the computer instructions from the computer-readable storage medium, and the processor executing the computer instructions to implement the above-described steering control method.

[0035] The beneficial effects of the technical solution provided in this application include at least the following:

[0036] By determining the front wheel steering angle and rear wheel steering angle based on the input steering angle of the front wheels and the vehicle's current speed, the steering angles of the front and rear wheels can be dynamically and independently controlled according to the driver's steering intention and the current vehicle speed. This improves the response speed and sensitivity of the vehicle's four-wheel steering, enhances maneuverability at low speeds and stability at high speeds, and improves the vehicle's steering performance. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of a vehicle steering process provided in an exemplary embodiment of this application;

[0039] Figure 2 This is a flowchart illustrating a steering control method provided in an exemplary embodiment of this application;

[0040] Figure 3 This is a flowchart illustrating a steering control method provided in an exemplary embodiment of this application;

[0041] Figure 4 This is a schematic diagram of vehicle parameters provided in an exemplary embodiment of this application;

[0042] Figure 5 This is a schematic diagram illustrating the process of determining parameters in a control model according to an exemplary embodiment of this application;

[0043] Figure 6 This is a schematic diagram illustrating the implementation process of four-wheel steering provided in an exemplary embodiment of this application;

[0044] Figure 7 This is a schematic diagram of the front wheel steering angle control curve and the rear wheel steering angle control curve provided in an exemplary embodiment of this application;

[0045] Figure 8 This is a schematic diagram of a centroid sideslip angle tracking curve provided in an exemplary embodiment of this application;

[0046] Figure 9 This is a schematic diagram of a yaw rate tracking curve provided in an exemplary embodiment of this application;

[0047] Figure 10 This is a schematic diagram of the structure of a steering control device provided in an exemplary embodiment of this application;

[0048] Figure 11 This is a structural block diagram of a computer device provided in an exemplary embodiment of this application.

[0049] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0051] Figure 1 This is a schematic diagram illustrating the process of controlling vehicle steering according to an exemplary embodiment of this application. Figure 1 As shown, upon receiving a steering angle control signal for the vehicle's front wheels, the onboard controller acquires the input steering angle corresponding to the steering angle control signal. The onboard controller also acquires the vehicle's current speed (V). The onboard controller obtains the corresponding reference model (G) of the vehicle. d (s))101, thereby determining the expected value (β) of the vehicle's center of gravity sideslip angle based on the input steering angle and current vehicle speed through the reference model 101. d ) and the expected value of the yaw rate (γ) d The reference model is a simulated dynamic model of the vehicle. Optionally, the on-board controller obtains the corresponding two-degree-of-freedom model of the vehicle, and then determines the reference model 101 based on the two-degree-of-freedom model, which is a dynamic model related to the yaw motion and lateral motion of the vehicle.

[0052] After obtaining the expected values ​​of the center of gravity sideslip angle and yaw rate corresponding to the vehicle's input steering angle and current speed, the vehicle controller will obtain the vehicle's actual center of gravity sideslip angle (β) and actual yaw rate (γ), and then, based on the first error (e... β ) and the second error (e γ The algebraic sum of the values ​​of the vehicle's front and rear wheel steering angles is used to determine the steering angles of the vehicle's front and rear wheels. The first error is the difference between the expected and actual sideslip angles, and the second error is the difference between the expected and actual yaw rates. Optionally, the onboard controller obtains the corresponding control model (G) of the vehicle. IMC (s))102, thereby determining the front wheel steering angle and rear wheel steering angle through the control model 102 based on the algebraic sum of the first error and the second error. The control model is a transfer function related to the vehicle's steering. Optionally, in the process of determining the front wheel steering angle and rear wheel steering angle through the control model 102, the on-board controller determines the front wheel steering angle and rear wheel steering angle based on the vehicle's corresponding internal model (G). M (s))103 Obtain the reference centroid sideslip angle (β) m ) and reference yaw rate (γ) mThe target algebraic sum is input into control model 102 to obtain the control quantity (u) output by control model 102, namely the front wheel steering angle and the rear wheel steering angle. Internal model 103 is determined based on the diagonal matrix of the corresponding vehicle model (G(s)) 104, which is the actual vehicle's dynamic model. The target algebraic sum is determined based on the algebraic sum of the reference centroid sideslip angle, the reference yaw rate, the first error, and the second error.

[0053] After determining the front wheel steering angle and the rear wheel steering angle, the onboard controller controls the front wheel steering based on the front wheel steering angle and the rear wheel steering based on the rear wheel steering angle, thereby achieving four-wheel steering. For example, the onboard controller inputs the front wheel steering angle and the rear wheel steering angle into the vehicle model (G(s))104 to control the front wheel steering based on the front wheel steering angle and the rear wheel steering based on the rear wheel steering angle. Figure 1 In this context, y represents the state of the vehicle after controlling the front wheel steering based on the front wheel steering angle and controlling the rear wheel steering based on the rear wheel steering angle.

[0054] By determining the front wheel steering angle and rear wheel steering angle based on the input steering angle of the front wheels and the vehicle's current speed, the steering angles of the front and rear wheels can be dynamically and independently controlled according to the driver's steering intention and the current vehicle speed. This improves the response speed and sensitivity of the vehicle's four-wheel steering, enhances maneuverability at low speeds and stability at high speeds, and improves the vehicle's steering performance.

[0055] Figure 2 This is a flowchart illustrating a steering control method provided in an exemplary embodiment of this application. The method can be used in vehicles, such as an onboard controller. Figure 2 As shown, the method includes:

[0056] Step 202: Upon receiving a steering angle control signal for the front wheels of the vehicle, acquire the input steering angle corresponding to the steering angle control signal.

[0057] The vehicle's drive type in this application embodiment includes at least one of front-wheel drive, rear-wheel drive, four-wheel drive, and multi-wheel drive. The vehicle's power source includes at least one of gasoline, diesel, electricity, hydrogen, and hybrid power. In some embodiments, the vehicle in this application embodiment includes, but is not limited to, gasoline-powered vehicles, pure electric vehicles, plug-in hybrid electric vehicles, hybrid electric vehicles, and range-extended hybrid electric vehicles. In some embodiments, the vehicle in this application embodiment refers to an electric vehicle.

[0058] The vehicle controller in this embodiment is integrated into the vehicle and is used to manage vehicle components. It should be noted that the vehicle controller in this embodiment can also be a controller for managing the vehicle's steering system.

[0059] In some embodiments, the vehicle in this application includes a four-wheeled vehicle. The two wheels symmetrically arranged at the front of the vehicle in the direction of travel are the front wheels, and the two wheels symmetrically arranged at the rear of the vehicle in the direction of travel are the rear wheels. The steering angles of the two front wheels and the two rear wheels change synchronously.

[0060] The steering angle control signal is used to control the steering angle of the vehicle's front wheels. Optionally, the steering angle control signal is triggered by the vehicle's driver by operating the steering wheel, by the vehicle's driver assistance system, or by the user of the vehicle through an application; this embodiment of the application does not impose any limitations on this. The application used to trigger the steering angle control signal controls the vehicle, and the application establishes a communication connection with the vehicle, such as the vehicle's onboard controller. The input steering angle is the steering angle indicated by the steering angle control signal to control the steering of the vehicle's front wheels.

[0061] Step 204: Determine the front wheel steering angle and rear wheel steering angle of the vehicle based on the input steering angle and the vehicle's current speed.

[0062] The current vehicle speed is the vehicle speed obtained by the vehicle controller at the target time. The target time can be the time when the vehicle controller receives the steering angle control signal or the time when the vehicle controller obtains the input steering angle.

[0063] The front wheel steering angle is used by the onboard controller to control the steering angle of the vehicle's front wheels, while the rear wheel steering angle is used by the onboard controller to control the steering angle of the vehicle's rear wheels. It should be noted that the front wheel steering angle determined by the onboard controller can be the same as or different from the input steering angle.

[0064] Optionally, the input steering angle is positively correlated with the front wheel steering angle and the rear wheel steering angle. That is, the larger the input steering angle, the larger the front wheel steering angle and the larger the rear wheel steering angle determined by the vehicle controller; the smaller the input steering angle, the smaller the front wheel steering angle and the smaller the rear wheel steering angle determined by the vehicle controller. Optionally, the current vehicle speed is negatively correlated with the front wheel steering angle and the rear wheel steering angle. That is, the higher the current vehicle speed, the smaller the front wheel steering angle and the smaller the rear wheel steering angle determined by the vehicle controller; the lower the current vehicle speed, the larger the front wheel steering angle and the larger the rear wheel steering angle determined by the vehicle controller.

[0065] Step 206: Control the front wheel steering of the vehicle based on the front wheel steering angle, and control the rear wheel steering of the vehicle based on the rear wheel steering angle.

[0066] After determining the steering angles of the front and rear wheels of the vehicle, the onboard controller will control the front wheels to steer according to the front wheel steering angle and the rear wheels to steer according to the rear wheel steering angle, thereby achieving four-wheel steering of the vehicle.

[0067] In some embodiments, the vehicle controller executes the method provided in this application embodiment at different times when it receives the steering angle control signal, so as to determine the front wheel steering angle and rear wheel steering angle of the vehicle at different times according to the steering angle control signal at different times, thereby realizing the control of the vehicle to perform four-wheel steering at different times.

[0068] In summary, the method provided in this embodiment determines the front wheel steering angle and the rear wheel steering angle based on the input steering angle of the front wheels and the current vehicle speed. This allows for dynamic and independent control of the steering angles of the front and rear wheels according to the driver's steering intention and the current vehicle speed. This improves the response speed and sensitivity of the vehicle's four-wheel steering, enhances maneuverability at low speeds and stability at high speeds, and improves the vehicle's steering performance.

[0069] Figure 3 This is a flowchart illustrating a steering control method provided in an exemplary embodiment of this application. The method can be used in vehicles, such as an onboard controller. Figure 3 As shown, the method includes:

[0070] Step 302: Upon receiving a steering angle control signal for the front wheels of the vehicle, acquire the input steering angle corresponding to the steering angle control signal.

[0071] The vehicle drive type in this application embodiment includes at least one of front-wheel drive, rear-wheel drive, four-wheel drive, and multi-wheel drive. The power source of the vehicle includes at least one of gasoline, diesel, electricity, hydrogen, and hybrid power. In some embodiments, the vehicle in this application embodiment includes, but is not limited to, gasoline-powered vehicles, pure electric vehicles, plug-in hybrid electric vehicles, hybrid electric vehicles, and range-extended hybrid electric vehicles. In some embodiments, the vehicle in this application embodiment refers to an electric vehicle. The on-board controller in this application embodiment is a controller integrated into the vehicle for managing vehicle components. It should be noted that the on-board controller in this application embodiment may be a controller for managing the vehicle's steering system.

[0072] In some embodiments, the vehicle in this application includes a four-wheeled vehicle. The two wheels symmetrically arranged at the front of the vehicle in the direction of travel are the front wheels, and the two wheels symmetrically arranged at the rear of the vehicle in the direction of travel are the rear wheels. The steering angles of the two front wheels and the two rear wheels change synchronously.

[0073] The steering angle control signal is used to control the steering angle of the vehicle's front wheels. Optionally, the steering angle control signal is triggered by the vehicle's driver by operating the steering wheel, by the vehicle's driver assistance system, or by the user of the vehicle through an application; this embodiment of the application does not impose any limitations on this. The application used to trigger the steering angle control signal controls the vehicle, and the application establishes a communication connection with the vehicle, such as the vehicle's onboard controller. The input steering angle is the steering angle indicated by the steering angle control signal to control the steering of the vehicle's front wheels.

[0074] Step 304: Based on the input steering angle and current vehicle speed, determine the expected value of the vehicle's center of gravity sideslip angle and yaw rate.

[0075] In some embodiments, the onboard controller acquires a reference model (G) corresponding to the vehicle. d (s) and, based on the input steering angle and current vehicle speed, determine the expected values ​​of the vehicle's center of gravity sideslip angle and yaw rate using a reference model. The reference model is a simulated dynamic model of the vehicle, which can be determined based on Internal Model Controller (IMC) theory. 's' represents a variable and can be in complex form. The expected value of the center of gravity sideslip angle is the desired value of the vehicle's center of gravity sideslip angle, which can also be understood as the ideal value of the center of gravity sideslip angle. The expected value of the yaw rate is the desired value of the vehicle's yaw rate, which can also be understood as the ideal value of the yaw rate. For an introduction to the center of gravity sideslip angle and yaw rate, please refer to the relevant content below.

[0076] Optionally, the vehicle controller obtains the corresponding two-degree-of-freedom model of the vehicle, and then determines the reference model based on the two-degree-of-freedom model. The two-degree-of-freedom model is a dynamic model related to the yaw motion and lateral motion of the vehicle, that is, the two-degree-of-freedom model only considers the two degrees of freedom of the vehicle's yaw motion and lateral motion.

[0077] The following describes the process of determining the two-degree-of-freedom model and the reference model based on the two-degree-of-freedom model, as well as the vehicle parameters used in the determination process.

[0078] For example, Figure 4 This is a schematic diagram illustrating vehicle parameters provided in an exemplary embodiment of this application. For example... Figure 4 As shown, the steering angle of the vehicle's front wheels is δ. fThe rear wheel steering angle is δ r The speed of the vehicle's front axle center point is u. f The speed of the rear axle center point of the vehicle is u. r The front wheel slip angle of the vehicle is α. f The rear wheel slip angle of the vehicle is α. r The lateral force on the front wheel of the vehicle is F. y_f The lateral force on the rear wheel of the vehicle is F. y_r The angle between the velocity of the vehicle's front axle center point and the x-axis is ξ. f The angle between the velocity of the rear axle center point of the vehicle and the x-axis is ξ. r The distance from the vehicle's center of gravity to the front axle is L. f The distance from the vehicle's center of gravity to the rear axle is L. r The vehicle's wheelbase is L. The vehicle's longitudinal speed is V. x The vehicle's lateral speed is V y The vehicle's speed is V. The vehicle's sideslip angle is β, and the vehicle's yaw rate is γ.

[0079] According to Newton's second law, the differential equations of motion for the vehicle with two degrees of freedom are as follows:

[0080]

[0081] Where m represents the mass of the vehicle, I z The · represents the rotational inertia of the vehicle, and the · in the formula represents the first derivative.

[0082] Based on the vehicle's geometric parameters and kinematic relationships, the front wheel slip angle and rear wheel slip angle are obtained as follows:

[0083]

[0084] Since the front and rear wheel slip angles are very small, we only consider the case where the tires are within the linear range, and obtain the front and rear wheel slip angles as follows:

[0085]

[0086] Where, k f k represents the lateral stiffness of the vehicle's front wheels. r This indicates the lateral stiffness of the vehicle's rear wheels.

[0087] Considering the vehicle's center of gravity sideslip angle is very small, therefore V x =Vcosβ=V, and V y =Vsinβ=Vβ, and Combining the above formulas (1)-(3), we finally obtain the linear two-degree-of-freedom dynamic differential equations (two-degree-of-freedom model) of the vehicle as follows:

[0088]

[0089] Let δ r =0, transforming the dynamic differential equation of formula (4) into state-space form, we obtain the following reference model of the vehicle:

[0090]

[0091] in, U d =[δ f ],

[0092] By performing a Laplace transform on the above formula (5), the final reference model can be obtained. After obtaining the input rotation angle... Given the current vehicle speed (V), by substituting into the above formula (5), the expected value of the vehicle's center of gravity sideslip angle (β) can be obtained. d ) and the expected value of the yaw rate (γ) d ).

[0093] Step 306: Obtain the vehicle's actual sideslip angle and actual yaw rate.

[0094] The vehicle's actual sideslip angle (β) is the sideslip angle of the vehicle under actual conditions, and the vehicle's actual yaw rate (γ) is the yaw rate of the vehicle under actual conditions. Optionally, the onboard controller can acquire the vehicle's actual sideslip angle and actual yaw rate through sensors installed in the vehicle.

[0095] Step 308: Determine the front wheel steering angle and the rear wheel steering angle based on the algebraic sum of the first error and the second error.

[0096] First error (e) β The second error (e) is the error between the expected and actual sideslip angle of the centroid, which can be determined based on the difference between the expected and actual sideslip angles. γ The yaw rate is the error between the expected value and the actual yaw rate, which can be determined based on the difference between the expected value and the actual yaw rate.

[0097] Optionally, the onboard controller acquires the control model (G) corresponding to the vehicle. IMC (s)), and based on the algebraic sum of the first error and the second error, the front wheel steering angle and the rear wheel steering angle are determined through the control model. The control model is a transfer function related to the vehicle's steering, and can be determined based on IMC theory.

[0098] Optionally, in the process of determining the front wheel steering angle and the rear wheel steering angle through the control model, the on-board controller determines the steering angle based on the vehicle's corresponding internal model (G). M The reference sideslip angle and reference yaw rate are obtained by acquiring the reference centroid sideslip angle and the reference yaw rate, and the target algebraic sum is input into the control model to obtain the front wheel steering angle and the rear wheel steering angle. The internal model is determined based on the diagonal matrix of the corresponding vehicle model (G(s)), which is the actual vehicle dynamics model. Both the internal model and the vehicle model can be determined based on IMC theory. The reference centroid sideslip angle is the sideslip angle output by the internal model, and the reference yaw rate is the yaw rate output by the internal model. The target algebraic sum is determined based on the algebraic sum of the reference centroid sideslip angle, the reference yaw rate, the first error, and the second error. Optionally, by inputting the target algebraic sum into the control model, the control quantity (u) output by the control model can be obtained, which includes the front wheel steering angle and the rear wheel steering angle.

[0099] The following describes the process of determining the vehicle model, internal model, and control model, as well as the process of determining the front wheel steering angle and the rear wheel steering angle.

[0100] By transforming the two-degree-of-freedom motion differential equations in the previous text into a state space and performing a Laplace transform, the transfer function of the whole vehicle model (i.e., the whole vehicle model) can be obtained as follows:

[0101]

[0102] Where, a0 = -k f k r L 2 -mV 2 (L f k f -L r k r ), a2=-mI z V 2 b 10 =-k f k r VL, b 11 =mV 2 l f k f b 20 =Lk f k r V, b 21 =-mL r k r V 2 b 30 =-k f k r Lr L-mV 2 L f k f b 31 =I z k f V, b 40 =-k f k r L f L+mL r k r V 2 b 41 =I z k r V.

[0103] Based on the transfer function G(s) of the whole vehicle model in formula (6), the determinant value |G| and the algebraic cofactor G of G(s) are calculated. ij And the corresponding zero-point order, we can obtain the diagonal matrix H(s) (i.e., the internal model) as follows:

[0104]

[0105] According to formula (7), the diagonal element k corresponding to the decoupling matrix K(s) can be obtained. ii (s) and off-diagonal element k ij (s) are as follows:

[0106]

[0107] Where |G| is the determinant of G(s), G ii and G ij h are the diagonal and off-diagonal elements of G(s). ii It is the diagonal element of matrix H(s).

[0108] By substituting equations (6) and (7) into equation (8), the decoupling matrix K(s) can be obtained as follows:

[0109]

[0110] Where, A2=mI z V 3 k f k r L, A0 = k f k r LV[mV 2 (L f k f -L r k r )+k f kr L 2 ], B 12 =mI z L f k f k r V 3 ,

[0111] According to the ideal controller characteristics of IMC theory, G is known. M (s)=H(s) and G IMC The symbols above indicate matrix inversion. Referring to the design of the univariate model, the expression for the IMC-FOF control matrix is ​​as follows:

[0112]

[0113] in, For a fractional-order filter (FOF) based on the theory of fractional-order filter, λ1 and λ2 are time constants, α1 and α2 are fractional orders, 0 < α1, α2 < 1.

[0114] Based on formulas (7) and (10), the IMC-FOF control matrix (i.e., control model) corresponding to the vehicle is obtained as follows:

[0115]

[0116] Among them, a0, a1, a2, b in formula (11) 10 b 11 b 40 and b 41 The meaning is consistent with the formula mentioned earlier.

[0117] The following section describes the process of determining the parameters in the control model.

[0118] Based on the error between the expected values ​​(expected values ​​of center of gravity sideslip angle and expected values ​​of yaw rate) obtained from the reference model and the actual values ​​(actual center of gravity sideslip angle and actual yaw rate) obtained from the vehicle model, the fitness function is designed as follows:

[0119]

[0120] Among them, e β Indicates the first error, e γ This indicates the second error. For example, Figure 5This is a schematic diagram illustrating the process of determining parameters in a control model according to an exemplary embodiment of this application. For example... Figure 5 As shown, in step A1, the population Q(t) is initialized, and n chromosomes (parameters) encoded by qubits are randomly generated; in step A2, each individual in the initial population Q(t) is examined to obtain the corresponding λ1, λ2 and α1, α2; in steps A3-A5, the fitness of each determined λ1, λ2 and α1, α2 is evaluated using formula (12); in step A6, the individual is adjusted using a quantum rotation gate to obtain a new population Q(t+1); in step A7, the optimal individual and its corresponding fitness are recorded; in step A8, the iteration number t is updated to t+1; in step A9, it is determined whether the calculation process can end. If the end condition is met, the process exits; otherwise, it continues.

[0121] After determining the parameters in the control model, the front wheel steering angle and the rear wheel steering angle can be obtained by substituting the target algebraic sum into the control model.

[0122] Step 310: Control the front wheel steering of the vehicle based on the front wheel steering angle, and control the rear wheel steering of the vehicle based on the rear wheel steering angle.

[0123] After determining the steering angles of the front and rear wheels of the vehicle, the onboard controller will control the front wheels to steer according to the front wheel steering angle and the rear wheels to steer according to the rear wheel steering angle, thereby achieving four-wheel steering of the vehicle.

[0124] In some embodiments, the vehicle controller executes the method provided in this application embodiment at different times when it receives the steering angle control signal, so as to determine the front wheel steering angle and rear wheel steering angle of the vehicle at different times according to the steering angle control signal at different times, thereby realizing the control of the vehicle to perform four-wheel steering at different times.

[0125] In summary, the method provided in this embodiment determines the front wheel steering angle and the rear wheel steering angle based on the input steering angle of the front wheels and the current vehicle speed. This allows for dynamic and independent control of the steering angles of the front and rear wheels according to the driver's steering intention and the current vehicle speed. This improves the response speed and sensitivity of the vehicle's four-wheel steering, enhances maneuverability at low speeds and stability at high speeds, and improves the vehicle's steering performance.

[0126] The method provided in this application provides a vehicle four-wheel steering control method based on IMC-FOF theory, which enables the steering angles of the front and rear wheels of the vehicle to be independently controlled according to the vehicle's driving state, solving the limitations of slow response and low sensitivity of traditional fixed steering transmission ratios. The four-wheel steering control method based on IMC-FOF theory can make the error of tracking the desired center of gravity sideslip angle and desired yaw rate during the vehicle's steering process close to zero, significantly improving the vehicle's path tracking ability and further improving the vehicle's driving stability.

[0127] For example, Figure 6 This is a schematic diagram illustrating the implementation process of four-wheel steering provided in an exemplary embodiment of this application. Figure 6 As shown, in step B1, the vehicle is simplified to a two-degree-of-freedom model. In step B2, the reference model of the vehicle is determined based on the two-degree-of-freedom model. In step B3, in implementing the four-wheel control method based on IMC-FOF theory, it is necessary to determine the vehicle's control model. In step B4, a fitness function is designed for the parameters in the control model. In step B5, the parameters in the control model are optimized using the fitness function to determine the final control model. The control model then determines the front wheel steering angle and the rear wheel steering angle based on the input steering angle and the current vehicle speed.

[0128] For example, Figure 7 This is a schematic diagram of the front wheel steering angle control curve and the rear wheel steering angle control curve provided in an exemplary embodiment of this application. Figure 7 As shown, IMC-FOF_Front represents the front wheel steering angle control curve under the four-wheel steering method provided in this application, and IMC-FOF_Rear represents the rear wheel steering angle control curve under the four-wheel steering method provided in this application. IMC_Front represents the front wheel steering angle control curve under the four-wheel steering method based on IMC theory, and IMC_Rear represents the rear wheel steering angle control curve under the four-wheel steering method based on IMC theory. PID_Front represents the front wheel steering angle control curve under the four-wheel steering method based on Proportional-Integral-Differential (PID) theory, and PID_Rear represents the rear wheel steering angle control curve under the four-wheel steering method based on PID theory.

[0129] Figure 8 This is a schematic diagram of a centroid sideslip angle tracking curve provided in an exemplary embodiment of this application. Figure 8As shown, Desired Value represents the expected value of the center of gravity sideslip angle tracking curve, IMC-FOF represents the center of gravity sideslip angle tracking curve under the four-wheel steering method provided in this application, IMC represents the center of gravity sideslip angle tracking curve under the four-wheel steering method based on IMC theory, and PID represents the center of gravity sideslip angle tracking curve under the four-wheel steering method based on PID theory.

[0130] Figure 9 This is a schematic diagram of a yaw rate tracking curve provided in an exemplary embodiment of this application. Figure 9 As shown, Desired Value represents the expected value of the yaw rate tracking curve, IMC-FOF represents the yaw rate tracking curve under the four-wheel steering method provided in this application, IMC represents the yaw rate tracking curve under the four-wheel steering method based on IMC theory, and PID represents the yaw rate tracking curve under the four-wheel steering method based on PID theory.

[0131] according to Figure 7-9 As can be seen, compared with IMC and PID, the intelligent four-wheel steering control method for vehicles based on IMC-FOF provided in this application has faster front and rear wheel angle response speeds and smaller overshoot, and can reach steady-state values ​​more quickly. The errors of the center-of-gravity sideslip angle and yaw rate with the desired values ​​are significantly reduced, with the yaw rate error reduced by 3.45% and 10.4%, respectively. This demonstrates that the intelligent four-wheel steering control method for vehicles based on IMC-FOF provided in this application enables independent control of the front and rear wheel angles according to the vehicle's driving state, overcoming the limitations of slow response and low sensitivity of traditional fixed steering ratios. The four-wheel steering control method designed based on IMC-FOF theory makes the error in tracking the desired center-of-gravity sideslip angle and desired yaw rate during steering approach zero, significantly improving the vehicle's path tracking ability and further enhancing its driving stability.

[0132] It should be noted that this application may display prompt interfaces, pop-ups, or output voice prompts before and during the collection of user data. These prompt interfaces, pop-ups, or voice prompts are used to inform the user that their data is being collected. This ensures that the application only begins the steps for collecting user data after receiving confirmation from the user regarding the prompt interface or pop-up; otherwise (i.e., without user confirmation), the steps for collecting user data end, meaning no user data is collected. In other words, all user data collected in this application is collected with the user's consent and authorization, and the collection, use, and processing of related user data must comply with the relevant laws, regulations, and standards of the relevant countries and regions.

[0133] It should be noted that the order of the method steps provided in the embodiments of this application can be appropriately adjusted, and the steps can also be added or removed as appropriate. Any method variations that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application, and therefore will not be elaborated further.

[0134] Figure 10 This is a schematic diagram of the structure of a steering control device provided in an exemplary embodiment of this application. Figure 10 As shown, the device includes:

[0135] The acquisition module 1001 is used to acquire the input steering angle corresponding to the steering angle control signal when a steering angle control signal for the front wheels of the vehicle is received.

[0136] The determining module 1002 is used to determine the front wheel steering angle and the rear wheel steering angle of the vehicle based on the input steering angle and the current vehicle speed.

[0137] The control module 1003 is used to control the front wheel steering of the vehicle according to the front wheel steering angle, and to control the rear wheel steering of the vehicle according to the rear wheel steering angle.

[0138] In an optional design, the determining module 1002 is used to:

[0139] Based on the input steering angle and the current vehicle speed, determine the expected value of the vehicle's center of gravity sideslip angle and the expected value of its yaw rate.

[0140] Obtain the actual sideslip angle and actual yaw rate of the vehicle.

[0141] The front wheel steering angle and the rear wheel steering angle are determined based on the algebraic sum of the first error and the second error.

[0142] Wherein, the first error is the error between the expected value of the centroid sideslip angle and the actual centroid sideslip angle, and the second error is the error between the expected value of the yaw rate and the actual yaw rate.

[0143] In an optional design, the determining module 1002 is used to:

[0144] Obtain the control model corresponding to the vehicle, wherein the control model is a transfer function related to the steering of the vehicle;

[0145] The front wheel steering angle and the rear wheel steering angle are determined by the control model based on the algebraic sum of the first error and the second error.

[0146] In an optional design, the determining module 1002 is used to:

[0147] The reference center of gravity sideslip angle and reference yaw rate are obtained based on the internal model corresponding to the vehicle. The internal model is determined based on the diagonal matrix of the whole vehicle model corresponding to the vehicle. The whole vehicle model is the actual dynamic model of the vehicle.

[0148] By inputting the target algebraic sum into the control model, the front wheel steering angle and the rear wheel steering angle are obtained;

[0149] The target algebraic sum is determined based on the algebraic sum of the reference centroid sideslip angle, the reference yaw rate, the first error, and the second error.

[0150] In an optional design, the determining module 1002 is used to:

[0151] Obtain a reference model corresponding to the vehicle, wherein the reference model is a simulated dynamic model of the vehicle;

[0152] Based on the input steering angle and the current vehicle speed, the expected value of the center of gravity sideslip angle and the expected value of the yaw rate are determined by the reference model.

[0153] In an optional design, the determining module 1002 is used to:

[0154] Obtain the two-degree-of-freedom model corresponding to the vehicle, wherein the two-degree-of-freedom model is a dynamic model related to the yaw motion and lateral motion of the vehicle;

[0155] The reference model is determined based on the two-degree-of-freedom model.

[0156] It should be noted that the steering control device provided in the above embodiments is only an example of the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the steering control device and the steering control method embodiments provided in the above embodiments belong to the same concept, and the specific implementation process can be found in the method embodiments, which will not be repeated here.

[0157] This application also provides a computer device, which includes a processor and a memory, wherein the memory stores at least one program; the processor is used to execute the at least one program in the memory to implement the steering control method provided in the above-described method embodiments.

[0158] Figure 11This is a structural block diagram of a computer device provided in an exemplary embodiment of this application. In some embodiments, the computer device is implemented as an in-vehicle controller. Typically, the computer device 1100 includes a processor 1101 and a memory 1102.

[0159] Processor 1101 may include one or more processing cores, such as a quad-core processor, an eleven-core processor, etc. Processor 1101 may be implemented using at least one hardware form selected from Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). Processor 1101 may also include a main processor and a coprocessor. The main processor, also known as a Central Processing Unit (CPU), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, processor 1101 may include a Graphics Processing Unit (GPU), which is responsible for rendering and drawing the content required to be displayed on the screen. In some embodiments, processor 1101 may also include an Artificial Intelligence (AI) processor, which is used to handle computational operations related to machine learning.

[0160] The memory 1102 may include one or more computer-readable storage media, which may be non-transitory. The memory 1102 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In some embodiments, the non-transitory computer-readable storage media in the memory 1102 are used to store at least one instruction, which is executed by the processor 1101 to implement the steering control method provided in the method embodiments of this application.

[0161] In some embodiments, the computer device 1100 may also optionally include an input interface 1103 and an output interface 1104. The processor 1101, memory 1102, and input interfaces 1103 and 1104 can be connected via a bus or signal lines. Various peripheral devices can be connected to the input interfaces 1103 and 1104 via buses, signal lines, or circuit boards. The input interfaces 1103 and 1104 can be used to connect at least one input / output related peripheral device to the processor 1101 and memory 1102.

[0162] In some embodiments, the processor 1101, memory 1102, and input interface 1103 and output interface 1104 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor 1101, memory 1102, and input interface 1103 and output interface 1104 can be implemented on separate chips or circuit boards, and the embodiments of this application do not limit this.

[0163] Those skilled in the art will understand that the structure shown above does not constitute a limitation on the computer device 1100, and may include more or fewer components than shown, or combine certain components, or employ different component arrangements.

[0164] In an exemplary embodiment, a chip is also provided, the chip including programmable logic circuitry and / or program instructions, which, when the chip is run on a computer device 1100, are used to implement the steering control method provided in the method embodiments of this application.

[0165] In an exemplary embodiment, a computer-readable storage medium is also provided, which stores at least one program that is loaded and executed by a processor to implement the steering control method provided in the method embodiments of this application.

[0166] In an exemplary embodiment, a computer program product is also provided, which includes computer instructions stored in a computer-readable storage medium. A processor retrieves the computer instructions from the computer-readable storage medium and executes the computer instructions to implement the steering control method provided in the method embodiments of this application.

[0167] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0168] Those skilled in the art will recognize that the functions described in the embodiments of this application in one or more of the above examples can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable storage medium or transmitted as one or more instructions or code on a computer-readable storage medium. Computer-readable storage media include computer storage media and communication media, wherein communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0169] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A steering control method, characterized in that, The method includes: Upon receiving a steering angle control signal for the front wheels of the vehicle, the input steering angle corresponding to the steering angle control signal is obtained; Based on the input steering angle and the current vehicle speed, determine the expected value of the vehicle's center of gravity sideslip angle and the expected value of its yaw rate. Obtain the actual sideslip angle and actual yaw rate of the vehicle; obtain the control model corresponding to the vehicle, wherein the control model is a transfer function related to the steering of the vehicle, and the control model is determined based on the internal model control (IMC) theory; The front wheel steering angle and the rear wheel steering angle are determined by the control model based on the algebraic sum of the first error and the second error; the first error is the error between the expected value of the center of gravity sideslip angle and the actual center of gravity sideslip angle, and the second error is the error between the expected value of the yaw rate and the actual yaw rate. The vehicle’s front wheel steering is controlled based on the front wheel steering angle, and the vehicle’s rear wheel steering is controlled based on the rear wheel steering angle.

2. The steering control method according to claim 1, characterized in that, The step of determining the front wheel steering angle and the rear wheel steering angle using the control model based on the algebraic sum of the first error and the second error includes: The reference center of gravity sideslip angle and reference yaw rate are obtained based on the internal model corresponding to the vehicle. The internal model is determined based on the diagonal matrix of the whole vehicle model corresponding to the vehicle. The whole vehicle model is the actual dynamic model of the vehicle. By inputting the target algebraic sum into the control model, the front wheel steering angle and the rear wheel steering angle are obtained; The target algebraic sum is determined based on the algebraic sum of the reference centroid sideslip angle, the reference yaw rate, the first error, and the second error.

3. The steering control method according to claim 1, characterized in that, The step of determining the expected values ​​of the vehicle's center of gravity sideslip angle and yaw rate based on the input steering angle and the vehicle's current speed includes: Obtain a reference model corresponding to the vehicle, wherein the reference model is a simulated dynamic model of the vehicle; Based on the input steering angle and the current vehicle speed, the expected value of the center of gravity sideslip angle and the expected value of the yaw rate are determined by the reference model.

4. The steering control method according to claim 3, characterized in that, The step of obtaining the reference model corresponding to the vehicle includes: Obtain the two-degree-of-freedom model corresponding to the vehicle, wherein the two-degree-of-freedom model is a dynamic model related to the yaw motion and lateral motion of the vehicle; The reference model is determined based on the two-degree-of-freedom model.

5. A steering control device, characterized in that, The device includes: The acquisition module is used to acquire the input steering angle corresponding to the steering angle control signal when a steering angle control signal for the front wheels of the vehicle is received. The determination module is used to determine the expected value of the vehicle's center of gravity sideslip angle and the expected value of the yaw rate based on the input steering angle and the vehicle's current speed; obtain the actual center of gravity sideslip angle and the actual yaw rate of the vehicle; obtain the control model corresponding to the vehicle, wherein the control model is a transfer function related to the vehicle's steering, and the control model is determined based on IMC theory; and determine the front wheel steering angle and the rear wheel steering angle through the control model based on the algebraic sum of a first error and a second error; wherein the first error is the error between the expected value of the center of gravity sideslip angle and the actual center of gravity sideslip angle, and the second error is the error between the expected value of the yaw rate and the actual yaw rate; A control module is used to control the front wheel steering of the vehicle according to the front wheel steering angle, and to control the rear wheel steering of the vehicle according to the rear wheel steering angle.

6. A computer device, characterized in that, The computer device includes a processor and a memory, wherein the memory stores at least one program; the processor is configured to execute the at least one program in the memory to implement the steering control method as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one program, which is loaded and executed by a processor to implement the steering control method as described in any one of claims 1 to 4.

8. A computer program product, characterized in that, The computer program product includes computer instructions stored in a computer-readable storage medium, from which a processor retrieves the computer instructions and executes the computer instructions to implement the steering control method as described in any one of claims 1 to 4.

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