Steering control method and device, equipment and storage medium

Abstract

The invention discloses a steering control method, device and equipment and a storage medium, and belongs to the technical field of vehicles. The method comprises the steps that under the condition that a steering angle control signal for front wheels of a vehicle is received, an input steering angle corresponding to the steering angle control signal is obtained; determining a front wheel steering angle and a rear wheel steering angle of the vehicle according to the input turning angle and the current vehicle speed of the vehicle; controlling front-wheel steering of the vehicle according to the front-wheel steering angle, and controlling rear-wheel steering of the vehicle according to the rear-wheel steering angle. The response speed and sensitivity of four-wheel steering of the vehicle are improved, the maneuverability of four-wheel steering of the vehicle under low-speed steering and the stability of four-wheel steering of the vehicle under high-speed steering are improved, and the steering performance of the vehicle is improved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicles, and particularly to a steering control method, device, equipment and storage medium. Background Art

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

[0003] In the related art, the four-wheel steering of the vehicle is usually realized by adopting a fixed steering transmission ratio. During the process of realizing the four-wheel steering of the vehicle, the vehicle will determine the rear-wheel steering angle corresponding to the front-wheel steering angle based on the front-wheel steering angle of the vehicle's front wheels controlled by the driver according to the fixed steering transmission ratio. Then, the vehicle's rear wheels are controlled to steer according to the determined rear-wheel steering angle to realize the four-wheel steering of the vehicle.

[0004] When the four-wheel steering of the vehicle is realized by adopting the above-mentioned fixed steering transmission ratio, the steering sensitivity of the vehicle is relatively low at low speeds, and the steering sensitivity is too high at high speeds, which is not conducive to the driver's control of the vehicle, and there is a problem of poor steering performance. Summary of the Invention

[0005] The present application provides a steering control method, device, equipment and storage medium, which can improve the steering performance of the vehicle. The technical solutions are as follows:

[0006] According to one aspect of the present application, a steering control method is provided, and the method includes:

[0007] When receiving a steering angle control signal for the vehicle's front wheels, obtaining an input rotation angle corresponding to the steering angle control signal;

[0008] Determining the front-wheel steering angle and rear-wheel steering angle of the vehicle according to the input rotation angle and the current vehicle speed of the vehicle;

[0009] Controlling the front wheels of the vehicle to steer according to the front-wheel steering angle, and controlling the rear wheels of the vehicle to steer according to the rear-wheel steering angle.

[0010] According to one aspect of the present application, a steering control device is provided, and the device includes:

[0011] An obtaining module, configured to obtain an input rotation angle corresponding to the steering angle control signal when receiving a steering angle control signal for the vehicle's front wheels;

[0012] A determination module, configured to determine the front-wheel steering angle and the rear-wheel steering angle of the vehicle according to the input steering angle and the current vehicle speed;

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

[0014] In an alternative design, the determination module is configured to:

[0015] Determine the expected value of the sideslip angle of the vehicle's center of mass and the expected value of the yaw rate according to the input steering angle and the current vehicle speed;

[0016] Obtain the actual sideslip angle of the vehicle's center of mass and the actual yaw rate;

[0017] Determine the front-wheel steering angle and the rear-wheel steering angle according to 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 sideslip angle of the center of mass and the actual sideslip angle of the center of mass, and the second error is the error between the expected value of the yaw rate and the actual yaw rate.

[0019] In an alternative design, the determination module is configured to:

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

[0021] Determine the front-wheel steering angle and the rear-wheel steering angle through the control model according to the algebraic sum of the first error and the second error.

[0022] In an alternative design, the determination module is configured to:

[0023] Obtain the reference sideslip angle of the center of mass and the reference yaw rate according to the internal model corresponding to the vehicle, and the internal model is determined according to the diagonal matrix of the vehicle's overall model, and the overall model is the dynamic model of the actual vehicle;

[0024] Input the target algebraic sum into the control model to obtain the front-wheel steering angle and the rear-wheel steering angle; ]>

[0025] Wherein, the target algebraic sum is determined according to the algebraic sum of the reference sideslip angle of the center of mass, the reference yaw rate, the first error and the second error.

[0026] In an alternative design, the determination module is configured to:

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

[0028] According to the input steering angle and the current vehicle speed, determine the expected value of the sideslip angle of the center of mass and the expected value of the yaw rate through the reference model.

[0029] In an alternative design, the determination module is configured to:

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

[0031] Determine the reference model according to the two-degree-of-freedom model.

[0032] According to another aspect of the embodiments of the present application, there is provided a computer device, which includes: a processor and a memory, and at least one segment of program is stored in the memory; the processor is configured to execute at least one segment of program in the memory to implement the above-mentioned steering control method.

[0033] According to another aspect of the embodiments of the present application, there is provided a computer-readable storage medium, in which at least one segment of program is stored, and the at least one segment of program is loaded and executed by a processor to implement the above-mentioned steering control method.

[0034] According to another aspect of the embodiments of the present application, there is provided a computer program product or a computer program, which includes computer instructions, the computer instructions are stored in a computer-readable storage medium, the processor obtains the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions to implement the above-mentioned steering control method.

[0035] The beneficial effects brought by the technical solution provided by the present application at least include:

[0036] By determining the front-wheel steering angle of the vehicle's front wheels and the rear-wheel steering angle of the vehicle's rear wheels according to the input steering angle of the vehicle's front wheels and the current vehicle speed of the vehicle, it is possible to dynamically and independently control the steering angle of the vehicle's front wheels and the steering angle of the vehicle's rear wheels according to the driver's steering intention and the current vehicle speed. The response speed and sensitivity of the vehicle's four-wheel steering are improved, the maneuverability of the vehicle's four-wheel steering at low speed and the stability at high speed are improved, and the steering performance of the vehicle is enhanced. Description of the Drawings

[0037] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0038] Figure 1 It is a schematic diagram of controlling the vehicle steering process provided by an exemplary embodiment of the present application;

[0039] Figure 2 It is a schematic flowchart of the steering control method provided by an exemplary embodiment of the present application;

[0040] Figure 3 It is a schematic flowchart of the steering control method provided by an exemplary embodiment of the present application;

[0041] Figure 4 It is a schematic diagram of the vehicle parameters provided by an exemplary embodiment of the present application;

[0042] Figure 5 It is a schematic diagram of the process of determining the parameters in the control model provided by an exemplary embodiment of the present application;

[0043] Figure 6 It is a schematic diagram of the implementation process of four-wheel steering provided by an exemplary embodiment of the present application;

[0044] Figure 7 It is a schematic diagram of the front wheel angle control curve and the rear wheel angle control curve provided by an exemplary embodiment of the present application;

[0045] Figure 8 It is a schematic diagram of the centroid side slip angle tracking curve provided by an exemplary embodiment of the present application;

[0046] Figure 9 It is a schematic diagram of the yaw rate tracking curve provided by an exemplary embodiment of the present application;

[0047] Figure 10 It is a schematic structural diagram of the steering control device provided by an exemplary embodiment of the present application;

[0048] Figure 11 It is a structural block diagram of the computer device provided by an exemplary embodiment of the present application.

[0049] The drawings here are incorporated into the specification and constitute a part of this specification, showing the embodiments in line with the present application, and are used together with the specification to explain the principles of the present application. Detailed implementation manners

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

[0051] Figure 1 It is a schematic diagram of controlling the vehicle steering process provided by an exemplary embodiment of this application. As Figure 1 shown, when receiving a steering angle control signal for the vehicle's front wheels, the in-vehicle controller obtains the input steering angle corresponding to the steering angle control signal The in-vehicle controller will also obtain the current vehicle speed (V). The in-vehicle controller determines the reference model (G d (s)) 101 corresponding to the vehicle, and thus, according to the input steering angle and the current vehicle speed, determines the expected value of the vehicle's center of mass sideslip angle (β d ) and the expected value of the yaw rate (γ d ) through the reference model 101. The reference model is a simulated dynamic model of the vehicle. Optionally, the in-vehicle controller determines the reference model 101 according to the two-degree-of-freedom model corresponding to the vehicle. The two-degree-of-freedom model is a dynamic model related to the vehicle's yaw motion and lateral motion.

[0052] After obtaining the expected value of the center of mass sideslip angle and the expected value of the yaw rate corresponding to the vehicle's input steering angle and the current vehicle speed, the in-vehicle controller will obtain the actual center of mass sideslip angle (β) and the actual yaw rate (γ) of the vehicle, and thus determine the front wheel steering angle and the rear wheel steering angle according to the algebraic sum of the first error (e β ) and the second error (e γ ). The first error is the error between the expected value of the center of mass sideslip angle and the actual center of mass sideslip angle, and the second error is the error between the expected value of the yaw rate and the actual yaw rate. Optionally, the in-vehicle controller determines the front wheel steering angle and the rear wheel steering angle through the control model (G IMC (s)) 102 corresponding to the vehicle, and thus, according to the algebraic sum of the first error and the second error, determines the front wheel steering angle and the rear wheel steering angle through the control model 102. 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 the rear wheel steering angle through the control model 102, the in-vehicle controller obtains the reference center of mass sideslip angle (β M ) and the reference yaw rate (γ m ) according to the internal model (G M (s)) 103 corresponding to the vehicle m) and input the target algebra into the input control model 102 to obtain the control quantity (u) output by the control model 102, that is, the front-wheel steering angle and the rear-wheel steering angle. The internal model 103 is determined according to the diagonal matrix of the vehicle's corresponding vehicle model (G(s)) 104, and the vehicle model 104 is the dynamic model of the actual vehicle. The target algebra is determined according to the algebraic sum of the reference sideslip angle of the centroid, the reference yaw rate, the first error, and the second error.

[0053] After determining the front-wheel steering angle of the vehicle's front wheels and the rear-wheel steering angle of the vehicle's rear wheels, the vehicle-mounted controller will control the front-wheel steering of the vehicle according to the front-wheel steering angle and control the rear-wheel steering of the vehicle according to the rear-wheel steering angle, so as to realize the four-wheel steering of the vehicle. For example, the vehicle-mounted controller inputs the front-wheel steering angle and the rear-wheel steering angle into the vehicle model (G(s)) 104, so as to realize the control of the vehicle's front-wheel steering according to the front-wheel steering angle and the control of the vehicle's rear-wheel steering according to the rear-wheel steering angle. Figure 1 In [the formula], y represents the state of the vehicle after controlling the front-wheel steering of the vehicle according to the front-wheel steering angle and controlling the rear-wheel steering of the vehicle according to the rear-wheel steering angle.

[0054] By determining the front-wheel steering angle of the vehicle's front wheels and the rear-wheel steering angle of the vehicle's rear wheels according to the input rotation angle of the vehicle's front wheels and the current vehicle speed, it is possible to dynamically and independently control the front-wheel steering angle and the rear-wheel steering angle of the vehicle according to the driver's steering intention and the current vehicle speed. The response speed and sensitivity of the vehicle's four-wheel steering are improved, the maneuverability of the vehicle's four-wheel steering at low speed and the stability at high speed are improved, and the steering performance of the vehicle is enhanced.

[0055] Figure 2 is a schematic flow chart of a steering control method provided by an exemplary embodiment of the present application. This method can be used for vehicles, such as the vehicle-mounted controller of a vehicle. As Figure 2 shown, this method includes:

[0056] Step 202: When receiving a steering angle control signal for the vehicle's front wheels, obtain the input rotation angle corresponding to the steering angle control signal.

[0057] The drive forms of the vehicle in the embodiments of the present application include at least one of front-wheel drive, rear-wheel drive, four-wheel drive, and multi-wheel drive. The power sources of the vehicle include at least one of gasoline, diesel, electricity, hydrogen, and hybrid power. In some embodiments, the vehicles in the embodiments of the present application include, but are not limited to, fuel vehicles, pure electric vehicles, plug-in hybrid vehicles, gasoline-electric hybrid vehicles, and extended-range hybrid vehicles. In some embodiments, the vehicles in the embodiments of the present application refer to electric vehicles.

[0058] The vehicle controller in the embodiments of the present application is integrated in a vehicle and is used to manage vehicle components. It should be noted that the vehicle controller in the embodiments of the present application can be a controller for managing the steering system of the vehicle.

[0059] In some embodiments, the vehicle in the embodiments of the present application includes a four-wheel vehicle. Among the four-wheel vehicles, the two wheels symmetrically arranged at the front part in the vehicle's forward direction are the front wheels, and the two wheels symmetrically arranged at the rear part in the vehicle's forward direction are the rear wheels. The steering angles of the two front wheels of the vehicle change synchronously, and the steering angles of the two rear wheels of the vehicle 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 driver by manipulating the steering wheel, or by the vehicle's assisted driving system, or by the vehicle's user through an application program. The embodiments of the present application do not limit this. The application program used to trigger the steering angle control signal is used to control the vehicle, and this application program is communicatively connected to the vehicle, such as the vehicle controller of the vehicle. The input steering angle is the steering angle indicated by the steering angle control signal for controlling the steering of the vehicle's front wheels.

[0061] Step 204: Determine the steering angles of the vehicle's front wheels and rear wheels according to the input steering angle and the current vehicle speed.

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

[0063] The front-wheel steering angle is used for the vehicle controller to control the steering angle of the vehicle's front wheels, and the rear-wheel steering angle is used for the vehicle 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 vehicle controller can be the same as the input steering angle 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 determined by the vehicle controller, 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 determined by the vehicle controller, 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 larger the current vehicle speed, the smaller the front-wheel steering angle determined by the vehicle controller, and the smaller the rear-wheel steering angle determined by the vehicle controller; the smaller the current vehicle speed, the larger the front-wheel steering angle determined by the vehicle controller, and the larger the rear-wheel steering angle determined by the vehicle controller.

[0065] Step 206: Control the front wheels of the vehicle to turn according to the front-wheel steering angle, and control the rear wheels of the vehicle to turn according to the rear-wheel steering angle.

[0066] After determining the front-wheel steering angle and the rear-wheel steering angle of the vehicle, the vehicle-mounted controller controls the front wheels of the vehicle to turn according to the indication of the front-wheel steering angle, and controls the rear wheels of the vehicle to turn according to the indication of the rear-wheel steering angle, so as to realize four-wheel steering of the vehicle.

[0067] In some embodiments, the vehicle-mounted controller executes the method provided in the embodiments of the present application at different moments when receiving the steering angle control signal, so as to determine the front-wheel steering angle and the rear-wheel steering angle of the vehicle at different moments according to the steering angle control signal at different moments, thereby realizing four-wheel steering of the vehicle at different moments.

[0068] In summary, the method provided in this embodiment can determine the front-wheel steering angle of the vehicle's front wheels and the rear-wheel steering angle of the vehicle's rear wheels by according to the input corner of the vehicle's front wheels and the current vehicle speed, and can realize dynamically and independently controlling the steering angle of the vehicle's front wheels and the steering angle of the vehicle's rear wheels according to the driver's steering intention and the current vehicle speed. It improves the response speed and sensitivity of the vehicle's four-wheel steering, improves the maneuverability of the vehicle's four-wheel steering at low-speed turning and the stability at high-speed turning, and enhances the steering performance of the vehicle.

[0069] Figure 3 It is a schematic flow chart of a steering control method provided by an exemplary embodiment of the present application. This method can be used for vehicles, such as the vehicle-mounted controller of a vehicle. As Figure 3 shown, this method includes:

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

[0071] The drive forms of the vehicles in the embodiments of the present application include at least one of front-wheel drive, rear-wheel drive, four-wheel drive, and multi-wheel drive. The power sources of the vehicles include at least one of gasoline, diesel, electricity, hydrogen, and hybrid power. In some embodiments, the vehicles in the embodiments of the present application include, but are not limited to, fuel vehicles, pure electric vehicles, plug-in hybrid vehicles, gasoline-electric hybrid vehicles, and extended-range hybrid vehicles. In some embodiments, the vehicles in the embodiments of the present application refer to electric vehicles. The vehicle-mounted controller in the embodiments of the present application is integrated in the vehicle and is used to manage the vehicle components. It should be noted that the vehicle-mounted controller in the embodiments of the present application can be a controller for managing the steering system of the vehicle.

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

[0073] The steering angle control signal is used to control the steering angle of the front wheels of the vehicle. Optionally, the steering angle control signal is triggered by the driver of the vehicle by manipulating the steering wheel, or triggered by the vehicle's assisted driving system, or triggered by the user of the vehicle through an application program. The embodiments of the present application do not limit this. The application program used to trigger the steering angle control signal is used to control the vehicle, and the application program is communicatively connected to the vehicle, such as the vehicle's on-vehicle controller. The input steering angle is the steering angle indicated by the steering angle control signal for controlling the front wheels of the vehicle to steer.

[0074] Step 304: Determine the expected value of the vehicle's center of mass side slip angle and the expected value of the yaw rate according to the input steering angle and the current vehicle speed.

[0075] In some embodiments, the on-vehicle controller obtains the reference model (G d (s)) corresponding to the vehicle, and determines the expected value of the vehicle's center of mass side slip angle and the expected value of the yaw rate through the reference model according to the input steering angle and the current vehicle speed. The reference model is a dynamic model of the simulated vehicle. The reference model can be determined based on the Internal Model Controller (IMC) theory. s represents a variable and can be in complex form. The expected value of the center of mass side slip angle is the expected value of the vehicle's center of mass side slip angle, and can also be understood as the ideal value of the center of mass side slip angle. The expected value of the yaw rate is the expected value of the vehicle's yaw rate, and can also be understood as the ideal value of the yaw rate. For the introduction of the center of mass side slip angle and the yaw rate, reference can be made to the relevant content in the following text.

[0076] Optionally, the on-vehicle controller determines the reference model by obtaining the two-degree-of-freedom model corresponding to the vehicle. 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 yaw motion and lateral motion of the vehicle.

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

[0078] Exemplarily, Figure 4 is a schematic diagram of the vehicle parameters provided by an exemplary embodiment of the present application. As Figure 4 shown, the steering angle of the front wheels of the vehicle is δ f, the rear wheel steering angle is δ r . The speed of the center point of the vehicle's front axle is u f , the speed of the center point of the vehicle's rear axle is u r . The side slip angle of the vehicle's front wheels is α f , the side slip angle of the vehicle's rear wheels is α r . The lateral force of the vehicle's front wheels is F y_f , the lateral force of the vehicle's rear wheels is F y_r . The angle between the speed of the center point of the vehicle's front axle and the x-axis is ξ f , the angle between the speed of the center point of the vehicle's rear axle and the x-axis is ξ r . The distance from the vehicle's center of mass position to the front axle is L f , the distance from the vehicle's center of mass position to the rear axle is L r , the wheelbase of the vehicle is L. The longitudinal speed of the vehicle is V x , the lateral speed of the vehicle is V y , the vehicle speed is V. The center of mass side slip angle of the vehicle is β, and the yaw angular velocity of the vehicle is γ.

[0079] According to Newton's second law, the two-degree-of-freedom motion differential equation of the vehicle is obtained as follows:

[0080]

[0081] Among them, m represents the mass of the vehicle, I z represents the moment of inertia of the vehicle, and the dot in the formula represents the first derivative.

[0082] According to the vehicle geometric parameters and kinematic relationships, the side slip angles of the vehicle's front wheels and rear wheels are obtained as follows:

[0083]

[0084] Since the values of the side slip angles of the vehicle's front wheels and rear wheels are very small, only the situation where the tire acts within the linear range is considered, and the side slip angles of the front wheels and rear wheels are obtained as follows:

[0085]

[0086] Among them, k f represents the side slip stiffness of the vehicle's front wheels, and k r represents the side slip stiffness of the vehicle's rear wheels.

[0087] Considering that the center of mass side slip angle of the vehicle is very small, so V x = Vcosβ = V, and V y = Vsinβ = Vβ, and Combining the above formulas (1)-(3), the linear two-degree-of-freedom dynamic differential equation (two-degree-of-freedom model) of the vehicle is finally obtained as follows:

[0088]

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

[0090]

[0091] where, U d = [δ f ,

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

[0093] Step 306: Obtain the actual sideslip angle at the center of mass and the actual yaw rate of the vehicle.

[0094] The actual sideslip angle at the center of mass (β) of the vehicle is the sideslip angle at the center of mass under actual conditions of the vehicle, and the actual yaw rate (γ) of the vehicle is the yaw rate under actual conditions of the vehicle. Optionally, the vehicle - mounted controller can obtain the actual sideslip angle at the center of mass and the actual yaw rate of the vehicle through sensors installed in the vehicle.

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

[0096] The first error (e β ) is the error between the expected value of the sideslip angle at the center of mass and the actual sideslip angle at the center of mass, which can be determined according to the difference between the expected value of the sideslip angle at the center of mass and the actual sideslip angle at the center of mass. The second error (e γ ) is the error between the expected value of the yaw rate and the actual yaw rate, which can be determined according to the difference between the expected value of the yaw rate and the actual yaw rate.

[0097] Optionally, the vehicle - mounted controller obtains the control model G IMC (s) corresponding to the vehicle, and determines the front - wheel steering angle and the rear - wheel steering angle through the control model according to the algebraic sum of the first error and the second error. Among them, the control model is a transfer function related to the steering of the vehicle, and the control model can be determined based on the IMC theory.

[0098] Optionally, during the process of determining the front-wheel steering angle and the rear-wheel steering angle through the control model, the vehicle-mounted controller obtains the reference sideslip angle of the center of mass and the reference yaw rate according to the internal model (G M (s)) of the vehicle, and inputs the target algebraic sum into the control model, so as to obtain the front-wheel steering angle and the rear-wheel steering angle. Among them, the internal model is determined according to the diagonal matrix of the vehicle's overall vehicle model (G(s)), the overall vehicle model is the dynamic model of the actual vehicle, and the internal model and the overall vehicle model can be determined based on the IMC theory. The reference sideslip angle of the center of mass is the sideslip angle of the center of mass 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 according to the algebraic sum of the reference sideslip angle of the center of mass, 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, and the control quantity includes the front-wheel steering angle and the rear-wheel steering angle.

[0099] The processes of determining the overall vehicle model, the internal model, and the control model, and the processes of determining the front-wheel steering angle and the rear-wheel steering angle are introduced below.

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

[0101]

[0102] Among them, 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] According to the transfer function G(s) of the vehicle model in formula (6), by calculating the determinant value |G| of G(s) and the cofactor G ij and the corresponding zero order, the diagonal matrix H(s) (i.e., the internal model) can be obtained as follows:

[0104]

[0105] According to formula (7), the diagonal elements k ii (s) and non - diagonal elements k ij (s) of the decoupling matrix K(s) can be obtained as follows:

[0106]

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

[0108] By substituting formula (6) and formula (7) into formula (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 the IMC theory, it is known that G M (s) = H(s) and G IMC The symbol above represents the inverse of the matrix. Referring to the design of the single-variable model, the expression of the IMC-FOF control matrix is obtained as follows:

[0112]

[0113] Among them, is a fractional-order filter under the fractional-order (Fractional-Order Filter, FOF) theory. λ1 and λ2 are time constants, and α1 and α2 are fractional-order orders, where 0 < α1, α2 < 1.

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

[0115]

[0116] Among them, a0, a1, a2, b 10 , b 11 , b 40 and b 41 in formula (11) have the same meaning as the formulas in the previous text.

[0117] The determination process of the parameters in the control model is introduced as follows.

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

[0119]

[0120] Among them, e β represents the first error, and e γ represents the second error. For example, Figure 5It is a schematic diagram of a process for determining parameters in a control model provided by an exemplary embodiment of the present application. As Figure 5 shown, in step A1, the population Q(t) is initialized, and n chromosomes (parameters) encoded with qubits are randomly generated; in step A2, each individual in the initial population Q(t) is inspected to obtain corresponding λ1, λ2 and α1, α2; in steps A3 - A5, fitness evaluation is performed on the determined λ1, λ2 and α1, α2 through formula (12); in step A6, individual adjustment is performed using a quantum rotation gate to obtain a new population Q(t + 1); in step A7, the optimal individual and the corresponding fitness are recorded; in step A8, the iteration number t is updated to t + 1; in step A9, it is judged 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, by substituting the target generation number and substituting it into the control model, the front-wheel steering angle and the rear-wheel steering angle can be obtained.

[0122] Step 310: Control the front wheels of the vehicle to steer according to the front-wheel steering angle, and control the rear wheels of the vehicle to steer according to the rear-wheel steering angle.

[0123] After the vehicle-mounted controller determines the front-wheel steering angle and the rear-wheel steering angle of the vehicle, it will control the front wheels of the vehicle to steer according to the indication of the front-wheel steering angle, and will control the rear wheels of the vehicle to steer according to the indication of the rear-wheel steering angle, so as to realize the four-wheel steering of the vehicle.

[0124] In some embodiments, the vehicle-mounted controller will execute the method provided by the embodiment of the present application at different moments of receiving the steering angle control signal, so as to determine the front-wheel steering angle and the rear-wheel steering angle of the vehicle at different moments according to the steering angle control signal at different moments, thereby realizing the four-wheel steering of the vehicle at different moments.

[0125] In summary, the method provided by this embodiment can determine the front-wheel steering angle of the vehicle's front wheels and the rear-wheel steering angle of the vehicle's rear wheels according to the input steering angle of the vehicle's front wheels and the current vehicle speed, and can realize the dynamic and independent control of the steering angle of the vehicle's front wheels and the steering angle of the vehicle's rear wheels according to the driver's steering intention and the current vehicle speed. It improves the response speed and sensitivity of the vehicle's four-wheel steering, improves the maneuverability of the vehicle's four-wheel steering at low speed and the stability at high speed, and enhances the steering performance of the vehicle.

[0126] The method provided by the embodiment of the present application provides a four-wheel steering control method for a vehicle based on the IMC-FOF theory, enabling the steering angles of the front and rear wheels of the vehicle to be independently controlled according to the driving state of the vehicle, and solving the limitations of slow response and low sensitivity of the traditional fixed steering transmission ratio; the four-wheel steering control method implemented based on the IMC-FOF theory can make the errors of tracking the desired sideslip angle of the centroid and the desired yaw rate approach zero during the steering driving process of the vehicle, significantly improving the path tracking ability of the vehicle and further enhancing the driving stability of the vehicle.

[0127] Exemplarily, Figure 6 is a schematic diagram of the implementation process of four-wheel steering provided by an exemplary embodiment of the present application. As Figure 6 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 according to the two-degree-of-freedom model. In step B3, in the process of implementing the four-wheel control method based on the IMC-FOF theory, the control model of the vehicle needs to be determined. 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 through the fitness function to determine the final control model, and the front-wheel steering angle and the rear-wheel steering angle of the vehicle are determined according to the input steering angle and the current vehicle speed through the control model.

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

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

[0130] Figure 9 is a schematic diagram of the yaw rate tracking curve provided by an exemplary embodiment of this application. As Figure 9 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 by 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 Figures 7 - 9 it can be seen that compared with IMC and PID, the front and rear wheel angle response speeds of the intelligent vehicle four-wheel steering control method based on IMC-FOF provided by this application are fast and the overshoot is small, and the steady-state value can be reached faster. The errors between the centroid sideslip angle, yaw rate and the expected value are significantly reduced, and the errors of the yaw rate are reduced by 3.45% and 10.4% respectively. It can be seen from this that the intelligent vehicle four-wheel steering control method based on IMC-FOF provided by this application enables the front and rear wheel angles to be independently controlled according to the vehicle driving state, solving the limitations of slow response and low sensitivity of the traditional fixed steering ratio. Designing the four-wheel steering control method based on IMC-FOF theory makes the errors of tracking the expected centroid sideslip angle and expected yaw rate during the steering driving process of the vehicle close to zero, significantly improving the vehicle's path tracking ability and further improving the vehicle's driving stability.

[0132] It should be noted that before and during the process of collecting relevant data of users by this application, a prompt interface, pop-up window or voice prompt information can be displayed. The prompt interface, pop-up window or voice prompt information is used to prompt the user that their relevant data is being collected currently, so that this application only starts to execute the relevant steps of obtaining the user's relevant data after obtaining the confirmation operation of the user on the prompt interface or pop-up window. Otherwise (that is, when the confirmation operation of the user on the prompt interface or pop-up window is not obtained), the relevant steps of obtaining the user's relevant data are ended, that is, the relevant data of the user is not obtained. In other words, all user data collected by this application is collected with the consent and authorization of the user, and the collection, use and processing of relevant user data need to comply with the relevant laws, regulations and standards of relevant countries and regions.

[0133] It should be noted that the order of the method steps provided in the embodiments of the present application can be appropriately adjusted, and the steps can also be increased or decreased accordingly according to the situation. Any person skilled in the art in the technical field disclosed in the present application can easily think of a changed method, which should be covered by the protection scope of the present application, so it will not be elaborated here.

[0134] Figure 10 It is a schematic structural diagram of a steering control device provided by an exemplary embodiment of the present application. As Figure 10 shown, the device includes:

[0135] An acquisition module 1001, configured to acquire an input steering angle corresponding to the steering angle control signal when receiving a steering angle control signal for the vehicle front wheels;

[0136] A determination module 1002, configured to determine the front wheel steering angle and the rear wheel steering angle of the vehicle according to the input steering angle and the current vehicle speed;

[0137] A control module 1003, configured to control the front wheels of the vehicle to steer according to the front wheel steering angle, and control the rear wheels of the vehicle to steer according to the rear wheel steering angle.

[0138] In an alternative design, the determination module 1002 is configured to:

[0139] Determine an expected value of the vehicle's center of mass sideslip angle and an expected value of the yaw rate according to the input steering angle and the current vehicle speed;

[0140] Acquire the actual center of mass sideslip angle and the actual yaw rate of the vehicle;

[0141] Determine the front wheel steering angle and the rear wheel steering angle according to 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 center of mass sideslip angle and the actual center of mass 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 alternative design, the determination module 1002 is configured to:

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

[0145] Determine the front wheel steering angle and the rear wheel steering angle through the control model according to the algebraic sum of the first error and the second error.

[0146] In an alternative design, the determining module 1002 is configured to:

[0147] Obtain a reference sideslip angle of the center of mass and a reference yaw rate according to the internal model corresponding to the vehicle, where the internal model is determined according to the diagonal matrix of the vehicle model corresponding to the vehicle, and the vehicle model is the dynamic model of the actual vehicle;

[0148] Input the target algebraic sum into the control model to obtain the front wheel steering angle and the rear wheel steering angle;

[0149] Wherein, the target algebraic sum is determined according to the algebraic sum of the reference sideslip angle of the center of mass, the reference yaw rate, the first error, and the second error.

[0150] In an alternative design, the determining module 1002 is configured to:

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

[0152] Determine the expected value of the sideslip angle of the center of mass and the expected value of the yaw rate through the reference model according to the input steering angle and the current vehicle speed.

[0153] In an alternative design, the determining module 1002 is configured to:

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

[0155] Determine the reference model according to the two-degree-of-freedom model.

[0156] It should be noted that: for the steering control device provided in the above embodiments, only the division of the above functional modules is used for illustration. In practical applications, the above functions can be allocated to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the steering control device provided in the above embodiments and the embodiments of the steering control method belong to the same concept. For the specific implementation process, please refer to the method embodiments, which will not be elaborated here.

[0157] An embodiment of the present application further provides a computer device, which includes: a processor and a memory, and at least one segment of program is stored in the memory; the processor is configured to execute at least one segment of program in the memory to implement the steering control method provided in each of the above method embodiments.

[0158] Figure 11It is a structural block diagram of a computer device provided by an exemplary embodiment of the present application. In some embodiments, the computer device is implemented as a vehicle-mounted controller. Generally, the computer device 1100 includes: a processor 1101 and a memory 1102.

[0159] The processor 1101 may include one or more processing cores, such as a 4-core processor, an 11-core processor, etc. The processor 1101 may be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), and programmable logic array (PLA). The processor 1101 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the wake state, also known as the central processing unit (CPU); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 1101 may include a graphics processing unit (GPU), and the GPU is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 1101 may further include an artificial intelligence (AI) processor, and the AI processor is used to process computational operations related to machine learning.

[0160] The memory 1102 may include one or more computer-readable storage media, and the computer-readable storage media 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 and flash storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 1102 is used to store at least one instruction, and the at least one instruction is used to be executed by the processor 1101 to implement the steering control method provided in the method embodiments of the present application.

[0161] In some embodiments, the computer device 1100 may further optionally include: an input interface 1103 and an output interface 1104. The processor 1101, the memory 1102, the input interface 1103, and the output interface 1104 may be connected through a bus or signal lines. Each peripheral device may be connected to the input interface 1103 and the output interface 1104 through a bus, signal lines, or a circuit board. The input interface 1103 and the output interface 1104 may be used to connect at least one input / output-related peripheral device to the processor 1101 and the memory 1102.

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

[0163] Those skilled in the art can understand that the structures shown above do not constitute a limitation on the computer device 1100, and it may include more or fewer components than shown in the figure, or combine certain components, or adopt different component arrangements.

[0164] In an exemplary embodiment, a chip is further provided, and the chip includes a programmable logic circuit and / or program instructions, which are used to implement the steering control method provided in the method embodiment of the present application when the chip runs on the computer device 1100.

[0165] In an exemplary embodiment, a computer-readable storage medium is further provided, and at least one segment of program is stored in the computer-readable storage medium, and the at least one segment of program is loaded and executed by the processor to implement the steering control method provided in the method embodiment of the present application.

[0166] In an exemplary embodiment, a computer program product is further provided, and the computer program product includes computer instructions, the computer instructions are stored in a computer-readable storage medium, the processor obtains the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions to implement the steering control method provided in the method embodiment of the present application.

[0167] Those of ordinary skill in the art can understand that all or part of the steps to implement the above embodiments can be completed by hardware, or can be completed by a program instructing relevant hardware, and the program can be stored in a computer-readable storage medium. The above-mentioned computer-readable storage medium may be a read-only memory, a magnetic disk, an optical disk, etc.

[0168] Those skilled in the art should be able to realize that in the above one or more examples, the functions described in the embodiments of the present application can be implemented by 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 codes on a computer-readable storage medium. The computer-readable storage medium includes computer storage media and communication media, where the communication media includes any medium that facilitates the transfer of a computer program from one place to another. The storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0169] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A steering control method, characterized in that, The method includes: When receiving a steering angle control signal for the front wheels of a vehicle, obtaining an input steering angle corresponding to the steering angle control signal; Determining a front-wheel steering angle and a rear-wheel steering angle of the vehicle according to the input steering angle and the current vehicle speed; Controlling the front-wheel steering of the vehicle according to the front-wheel steering angle, and controlling the rear-wheel steering of the vehicle according to the rear-wheel steering angle.

2. The method according to claim 1, wherein The determining the front-wheel steering angle and the rear-wheel steering angle of the vehicle according to the input steering angle and the current vehicle speed includes: Determining an expected value of the sideslip angle of the vehicle's center of mass and an expected value of the yaw rate according to the input steering angle and the current vehicle speed; Obtaining the actual sideslip angle of the vehicle's center of mass and the actual yaw rate; Determining the front-wheel steering angle and the rear-wheel steering angle according to the algebraic sum of a first error and a second error; Wherein, the first error is the error between the expected value of the sideslip angle of the center of mass and the actual sideslip angle of the center of mass, and the second error is the error between the expected value of the yaw rate and the actual yaw rate.

3. The method according to claim 2, wherein The determining the front-wheel steering angle and the rear-wheel steering angle according to the algebraic sum of the first error and the second error includes: Obtaining a control model corresponding to the vehicle, where the control model is a transfer function related to the steering of the vehicle; Determining the front-wheel steering angle and the rear-wheel steering angle through the control model according to the algebraic sum of the first error and the second error.

4. The method according to claim 3, characterized in that, The determining the front-wheel steering angle and the rear-wheel steering angle through the control model according to the algebraic sum of the first error and the second error includes: Obtaining a reference sideslip angle of the center of mass and a reference yaw rate according to an internal model corresponding to the vehicle, where the internal model is determined according to the diagonal matrix of the vehicle's overall model, and the overall model is the dynamic model of the actual vehicle; Inputting the target algebraic sum into the control model to obtain the front-wheel steering angle and the rear-wheel steering angle; Wherein, the target algebraic sum is determined according to the algebraic sum of the reference sideslip angle of the center of mass, the reference yaw rate, the first error, and the second error.

5. The method according to claim 2, characterized in that, The determining the expected value of the sideslip angle of the vehicle's center of mass and the expected value of the yaw rate according to the input steering angle and the current vehicle speed includes: Obtaining a reference model corresponding to the vehicle, where the reference model is a simulated dynamic model of the vehicle; Determining the expected value of the sideslip angle of the center of mass and the expected value of the yaw rate through the reference model according to the input steering angle and the current vehicle speed.

6. The method according to claim 5, wherein The obtaining the reference model corresponding to the vehicle includes: Obtaining a two-degree-of-freedom model corresponding to the vehicle, where the two-degree-of-freedom model is a dynamic model related to the yaw motion and the lateral motion of the vehicle; Determining the reference model according to the two-degree-of-freedom model.

7. A steering control device, characterized in that, The device includes: An obtaining module, configured to obtain an input steering angle corresponding to the steering angle control signal when receiving a steering angle control signal for the front wheels of a vehicle; A determination module, configured to determine the front-wheel steering angle and the rear-wheel steering angle of the vehicle according to the input steering angle and the current vehicle speed of the vehicle; A control module, configured to control the front-wheel steering of the vehicle according to the front-wheel steering angle and control the rear-wheel steering of the vehicle according to the rear-wheel steering angle.

8. A computer device, characterized in that, The computer device includes: a processor and a memory, and at least one segment of program is stored in the memory; the processor is configured to execute the at least one segment of program in the memory to implement the steering control method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, At least one segment of program is stored in the computer-readable storage medium, and the at least one segment of program is loaded and executed by a processor to implement the steering control method according to any one of claims 1 to 6.

10. A computer program product, characterized in that, The computer program product includes computer instructions, the computer instructions are stored in a computer-readable storage medium, the processor obtains the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions to implement the steering control method according to any one of claims 1 to 6.

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