Vehicle transverse control method, device, equipment, medium and product

Abstract

The invention provides a vehicle transverse control method, device and equipment, a medium and a product, and relates to the technical field of intelligent driving. The method comprises the following steps: acquiring vehicle information and a steering wheel angle change rate; an outer-layer controller is called to calculate an expected front wheel turning angle according to the planned position information, the actual position information, the vehicle body basic information and the longitudinal speed information; an inner-layer controller is called to calculate front wheel lateral force, reaction torque applied to a sector gear is calculated according to the front wheel lateral force, then the rotation angle of a second torsion bar is calculated, and expected motor torque and expected steering wheel rotation angle are obtained through calculation according to the rotation angle of the second torsion bar and the steering wheel rotation angle change rate; and finally, calling an inner-layer controller to control motor operation according to the expected motor torque, and controlling a steering wheel to rotate according to the expected steering wheel angle. The method is used for improving the accuracy of transverse control of the heavy vehicle by fully considering the nonlinear relation between the steering wheel rotation angle and the front wheel rotation angle of the vehicle.

Description

Technical Field

[0001] The present application relates to the field of intelligent driving technology, and in particular to a vehicle lateral control method, device, equipment, medium and product. Background Art

[0002] During the intelligent driving of heavy vehicles, lateral control is crucial to ensure the safe, stable and efficient operation of the vehicle.

[0003] In the prior art, the lateral control method of a heavy vehicle generally includes the following steps: first, calculating the desired front wheel angle according to a chassis dynamics model; then, converting the desired front wheel angle into a desired steering wheel angle and a desired motor torque through a preset proportional relationship; finally, performing lateral control on the heavy vehicle according to the desired steering wheel angle and the desired motor torque.

[0004] However, existing lateral control methods for heavy vehicles have the problem of poor lateral control accuracy. Summary of the invention

[0005] The present application provides a vehicle lateral control method, device, equipment, medium and product, which are used to improve the accuracy of lateral control of heavy vehicles.

[0006] In a first aspect, the present application provides a vehicle lateral control method, which is applied to an electric hydraulic steering system, wherein the electric hydraulic steering system comprises: a steering actuator, a hydraulic power module and a wheel system, wherein the steering actuator comprises: a steering wheel, a steering column, a first torsion bar, a reducer and a motor, wherein the hydraulic power module comprises: a second torsion bar, a screw rod, a sector gear, a steering drop arm and a cylinder, wherein the cylinder comprises a piston and a cylinder body, wherein the wheel system comprises: a front wheel and a steering tie rod, wherein two ends of the steering column are respectively connected to the steering wheel and one end of the first torsion bar, wherein the other end of the first torsion bar and the motor are both connected to the reducer, wherein two ends of the second torsion bar are respectively connected to the reducer and one end of the screw rod, wherein the other end of the screw rod is connected to the piston, and the piston is connected to the sector gear; wherein two ends of the steering drop arm are respectively connected to the sector gear and one end of the steering tie rod, and the other end of the steering tie rod is connected to the front wheel;

[0007] The method includes:

[0008] Obtain vehicle information and steering wheel angle change rate. The steering wheel angle change rate includes: first-order differential and second-order differential of the steering wheel angle. Vehicle information includes: basic vehicle body information, longitudinal speed information, actual position information and planned position information. The planned position information is the position information closest to the actual position information in the pre-generated planned path. Basic vehicle body information includes: wheel lateral stiffness, distance from vehicle center of mass to front wheel, distance from vehicle center of mass to rear wheel, vehicle mass, and vehicle moment of inertia.

[0009] Call the outer controller to calculate the expected front wheel turning angle according to the planned position information, actual position information, vehicle body basic information, and longitudinal speed information;

[0010] The inner controller is called to calculate the lateral force of the front wheel, and the reaction torque applied to the sector gear is calculated according to the lateral force of the front wheel;

[0011] The inner controller is called to calculate the rotation angle of the second torsion bar according to the reaction torque, and the desired motor torque is calculated according to the rotation angle of the second torsion bar and the steering wheel angle change rate;

[0012] The inner controller is called to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and the desired steering wheel angle is calculated according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio. The preset reduction ratio is the reduction ratio between the screw and the sector gear. The desired steering wheel angle is the sum of the rotation angle of the second torsion bar and the screw rotation angle of the screw. The screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio.

[0013] The inner controller is called to control the motor operation according to the desired motor torque, and the inner controller is called to control the steering wheel rotation according to the desired steering wheel angle.

[0014] In a possible design, the expected front wheel turning angle is calculated according to the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information, including:

[0015] Determine the position error and the direction error according to the planned position information and the actual position information, and generate the position error change rate and the direction error change rate according to the position errors at multiple moments and the direction errors at multiple moments;

[0016] The basic vehicle body information, longitudinal speed information, position error, direction error, position error change rate and direction error change rate are input into the vehicle's state space equation to calculate the desired front wheel steering angle.

[0017] In a possible design, the vehicle information also includes: lateral acceleration, and calculation of the front wheel lateral force includes:

[0018] The lateral acceleration, the distance from the vehicle center of mass to the front wheel, the distance from the vehicle center of mass to the rear wheel, the vehicle mass, and the vehicle moment of inertia are input into the monorail vehicle dynamic model to obtain the front wheel lateral force.

[0019] In one possible design, the front wheel lateral force is calculated, including:

[0020] Constructing the error vector of the sliding film observer, the error vector includes: yaw rate error, front wheel lateral force error and rear wheel lateral force error;

[0021] Iteratively training the synovial observer according to the error vector to obtain multiple gains of the synovial observer;

[0022] Predicting the front wheel lateral force through multiple gains of the sliding film observer;

[0023] The formula for predicting the lateral force of the front wheel by the sliding film observer is as follows:

[0024]

[0025] in, To predict the yaw rate, I is the vehicle moment of inertia, a is the distance from the vehicle center of mass to the front wheel, b is the distance from the vehicle center of mass to the rear wheel, ρ1 to ρ6 are the six gains of the sliding film observer, is the predicted front wheel lateral force, is the predicted rate of change of the front wheel lateral force, is the predicted rear wheel lateral force, is the predicted rate of change of the rear wheel lateral force, is the actual yaw angular velocity, a y is the actual lateral acceleration, is the predicted lateral acceleration, and sgn is a function with positive and negative signs.

[0026] In one possible design, the reaction torque applied to the sector gear is calculated based on the front wheel lateral force, including:

[0027] Get the axle distance of the vehicle, which is the distance between the wheel and the axle center;

[0028] The product of the front wheel lateral force, the wheel axle distance and the preset proportional coefficient is calculated to obtain the reaction torque.

[0029] In a possible design, the rotation angle of the second torsion bar is calculated according to the reaction torque, including:

[0030] Get the system information of the electric hydraulic steering system, including: piston side area A of the piston P , radius R of sector gear sg , Internal structural parameters of steering actuator C n , Flow leakage coefficient K between cylinder and piston le , the pressure difference ΔP between the upper and lower chambers of the cylinder, the preset reduction ratio i sg , the stiffness of the second torsion bar K t ;

[0031] Inputting the system information and the reaction torque into the second torsion bar angle calculation model to obtain the rotation angle of the second torsion bar;

[0032] Among them, the second torsion bar angle calculation model is as follows:

[0033]

[0034] sgn(ΔP) is the sign of ΔP, τ P is the reaction torque, a t is the rotation angle of the second torsion bar.

[0035] In a possible design, the expected motor torque is calculated according to the rotation angle of the second torsion bar and the steering wheel angle change rate, including:

[0036] calculating the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar as the torque of the second torsion bar;

[0037] Get the steering actuator information, including the equivalent inertia J of the steering actuator s , damping coefficient f of steering actuator vs , Friction coefficient f of steering actuator sf ;

[0038] Input the steering actuator information, the torque of the second torsion bar and the steering wheel angle change rate into the torque calculation model to obtain the expected motor torque;

[0039] The torque calculation model is as follows:

[0040]

[0041] and are the first and second order differentials of the steering wheel angle, τ s is the desired motor torque, τ t is the torque of the second torsion bar.

[0042] In a second aspect, the present application provides a vehicle lateral control device, which is applied to an electric hydraulic steering system. The electric hydraulic steering system includes: a steering actuator, a hydraulic power module and a wheel system. The steering actuator includes: a steering wheel, a steering column, a first torsion bar, a reducer and a motor. The hydraulic power module includes: a second torsion bar, a screw rod, a sector gear, a steering drop arm and a cylinder. The cylinder includes a piston and a cylinder body. The wheel system includes: a front wheel and a steering tie rod. The two ends of the steering column are respectively connected to the steering wheel and one end of the first torsion bar. The other end of the first torsion bar and the motor are both connected to the reducer. The two ends of the second torsion bar are respectively connected to the reducer and one end of the screw rod. The other end of the screw rod is connected to the piston, and the piston is connected to the sector gear. The two ends of the steering drop arm are respectively connected to the sector gear and one end of the steering tie rod. The other end of the steering tie rod is connected to the front wheel.

[0043] The device includes:

[0044] An acquisition module is used to acquire vehicle information and steering wheel angle change rate. The steering wheel angle change rate includes: first-order differential and second-order differential of the steering wheel angle. The vehicle information includes: basic vehicle body information, longitudinal speed information, actual position information and planned position information. The planned position information is the position information closest to the actual position information in the pre-generated planned path. The basic vehicle body information includes: wheel lateral stiffness, distance from the vehicle center of mass to the front wheel, distance from the vehicle center of mass to the rear wheel, vehicle mass, and vehicle moment of inertia.

[0045] The outer control module is used to call the outer controller to calculate the expected front wheel turning angle according to the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information;

[0046] A first inner layer control module is used to call the inner layer controller to calculate the lateral force of the front wheel, and calculate the reaction torque applied to the sector gear according to the lateral force of the front wheel;

[0047] A second inner control module is used to call the inner controller to calculate the rotation angle of the second torsion bar according to the reaction torque, and calculate the expected motor torque according to the rotation angle of the second torsion bar and the steering wheel angle change rate;

[0048] a third inner control module, for calling the inner controller to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and to calculate the desired steering wheel angle according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, wherein the preset reduction ratio is the reduction ratio between the screw and the sector gear, and the desired steering wheel angle is the sum of the rotation angle of the second torsion bar and the screw rotation angle of the screw, and the screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio;

[0049] The fourth inner control module is used to call the inner controller to control the motor operation according to the expected motor torque, and call the inner controller to control the steering wheel rotation according to the expected steering wheel angle.

[0050] In one possible design, the outer control module includes: an error change rate module and a first input module;

[0051] An error change rate module is used to determine the position error and the direction error according to the planned position information and the actual position information, and generate the position error change rate and the direction error change rate according to the position errors at multiple moments and the direction errors at multiple moments;

[0052] The first input module is used to input vehicle body basic information, longitudinal speed information, position error, direction error, position error change rate and direction error change rate into the state space equation of the vehicle to calculate the expected front wheel turning angle.

[0053] In one possible design, the first inner control module includes: a module for calculating the front wheel lateral force;

[0054] The module for calculating the lateral force of the front wheel is used to input the lateral acceleration, the distance from the center of mass of the vehicle to the front wheel, the distance from the center of mass of the vehicle to the rear wheel, the vehicle mass, and the vehicle moment of inertia into the monorail vehicle dynamic model to obtain the lateral force of the front wheel.

[0055] In a possible design, the module for calculating the front wheel lateral force further includes: a construction module, an iteration module and a prediction module;

[0056] A construction module is used to construct an error vector of a sliding film observer, wherein the error vector includes: a yaw rate error, a front wheel lateral force error, and a rear wheel lateral force error;

[0057] An iteration module, used for iteratively training the synovial observer according to the error vector to obtain multiple gains of the synovial observer;

[0058] A prediction module, for predicting the front wheel lateral force through a plurality of gains of a sliding film observer;

[0059] The formula for predicting the lateral force of the front wheel by the sliding film observer is as follows:

[0060]

[0061] in, To predict the yaw rate, I is the vehicle moment of inertia, a is the distance from the vehicle center of mass to the front wheel, b is the distance from the vehicle center of mass to the rear wheel, ρ1 to ρ6 are the six gains of the sliding film observer, is the predicted front wheel lateral force, is the predicted rate of change of the front wheel lateral force, is the predicted rear wheel lateral force, is the predicted rate of change of the rear wheel lateral force, is the actual yaw angular velocity, a y is the actual lateral acceleration, is the predicted lateral acceleration, and sgn is a function with positive and negative signs.

[0062] In a possible design, the first inner layer control module further includes: an axle distance module and a first product module:

[0063] The axle distance module is used to obtain the axle distance of the vehicle. The axle distance is the distance between the wheel and the axle center.

[0064] The first product module is used to calculate the product of the front wheel lateral force, the wheel axle distance and a preset proportional coefficient to obtain a reaction torque.

[0065] In one possible design, the second inner control module includes: a system information acquisition module and a second input module;

[0066] The system information acquisition module is used to acquire the system information of the electric hydraulic steering system. The system information includes: the piston side area A of the piston P , radius R of sector gear sg , Internal structural parameters of steering actuator C n , Flow leakage coefficient K between cylinder and piston le , the pressure difference ΔP between the upper and lower chambers of the cylinder, the preset reduction ratio i sg , the stiffness of the second torsion bar K t ;

[0067] A second input module, used for inputting system information and reaction torque into a second torsion bar angle calculation model to obtain a rotation angle of the second torsion bar;

[0068] Among them, the second torsion bar angle calculation model is as follows:

[0069]

[0070] sgn(ΔP) is the sign of ΔP, τ P is the reaction torque, a t is the rotation angle of the second torsion bar.

[0071] In a possible design, the second inner control module further includes: a second product module, an actuator information acquisition module, and a third input module;

[0072] A second product module, used for calculating the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar as the torque of the second torsion bar;

[0073] The actuator information acquisition module is used to acquire the steering actuator information, including the equivalent inertia J of the steering actuator. s , damping coefficient f of steering actuator vs , Friction coefficient f of steering actuator sf ;

[0074] A third input module is used to input the steering actuator information, the torque of the second torsion bar and the steering wheel angle change rate into the torque calculation model to obtain the expected motor torque;

[0075] The torque calculation model is as follows:

[0076]

[0077] and are the first and second order differentials of the steering wheel angle, τ s is the desired motor torque, τ t is the torque of the second torsion bar.

[0078] In a third aspect, the present application provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor;

[0079] Memory stores computer-executable instructions;

[0080] The processor executes the computer-executable instructions stored in the memory to implement a vehicle lateral control method according to the first aspect of the invention.

[0081] In a fourth aspect, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement a vehicle lateral control method according to the invention content of the first aspect.

[0082] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, is used to implement a vehicle lateral control method according to the invention content of the first aspect.

[0083] The present application provides a vehicle lateral control method, device, equipment, medium and product. The vehicle lateral control method is applied to an electric hydraulic steering system. The electric hydraulic steering system includes: a steering actuator, a hydraulic power module and a wheel system. The steering actuator includes: a steering wheel, a steering column, a first torsion bar, a reducer and a motor. The hydraulic power module includes: a second torsion bar, a screw rod, a sector gear, a steering drop arm and a cylinder. The cylinder includes a piston and a cylinder body. The wheel system includes: a front wheel and a steering rod. The two ends of the steering column are respectively connected to the steering wheel and one end of the first torsion bar. The other end of the first torsion bar and the motor are connected to reducer, two ends of the second torsion bar are respectively connected to the reducer and one end of the screw, the other end of the screw is connected to the piston, and the piston is connected to the sector gear; two ends of the steering drop arm are respectively connected to the sector gear and one end of the steering tie rod, and the other end of the steering tie rod is connected to the front wheel; the method includes: obtaining vehicle information and steering wheel angle change rate, the steering wheel angle change rate includes: the first-order differential and the second-order differential of the steering wheel angle, the vehicle information includes: vehicle body basic information, longitudinal speed information, actual position information and planned position information, the planned position information is the closest distance to the actual position information in the pre-generated planned path The basic vehicle body information includes: wheel lateral stiffness, distance from vehicle center of mass to front wheel, distance from vehicle center of mass to rear wheel, vehicle mass, and vehicle moment of inertia; the outer controller is called to calculate the desired front wheel steering angle according to the planned position information, actual position information, vehicle body basic information, and longitudinal speed information; the inner controller is called to calculate the front wheel lateral force, and the reaction torque applied to the sector gear is calculated according to the front wheel lateral force; the inner controller is called to calculate the rotation angle of the second torsion bar according to the reaction torque, and the desired electric motor torque; calling the inner controller to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and calculating the desired steering wheel angle according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, the preset reduction ratio is the reduction ratio between the screw and the sector gear, the desired steering wheel angle is the sum of the rotation angle of the second torsion bar and the screw rotation angle of the screw, the screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio; calling the inner controller to control the motor operation according to the desired motor torque, and calling the inner controller to control the steering wheel rotation according to the desired steering wheel angle. The following technical effects are achieved: the outer controller calculates the expected front wheel angle of the vehicle according to the vehicle information, and then the inner controller calculates the expected steering wheel angle and the expected motor torque that are nonlinearly related to the expected front wheel angle of the vehicle according to the expected front wheel angle and the vehicle information, thereby reducing the error between the expected steering wheel angle and the actual demand of the vehicle; the motor operation is controlled according to the expected motor torque by calling the inner controller, and the steering wheel rotation is controlled according to the expected steering wheel angle by calling the inner controller, thereby improving the accuracy of lateral control of heavy vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0085] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0086] Figure 1 A schematic diagram of the structure of an electric hydraulic steering system provided in an embodiment of the present application;

[0087] Figure 2 A schematic diagram of a vehicle lateral control method provided in an embodiment of the present application Figure 1 ;

[0088] Figure 3 A schematic diagram of a vehicle lateral control method provided in an embodiment of the present application Figure 2 ;

[0089] Figure 4 A schematic diagram of the structure of a vehicle lateral control device provided in an embodiment of the present application;

[0090] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0091] Reference numerals:

[0092] 110-steering actuator; 120-hydraulic power module; 130-wheel system; 111-steering wheel; 112-steering column; 113-first torsion bar; 114-reducer; 115-motor; 121-second torsion bar; 122-screw rod; 123-sector gear; 124-steering drop arm; 125-cylinder; 126-piston; 127-cylinder body; 128-servo valve; 129-electric pump; 131-front wheel; 132-steering tie rod;

[0093] 410 - acquisition module; 420 - outer layer control module; 430 - first inner layer control module; 440 - second inner layer control module; 450 - third inner layer control module; 460 - fourth inner layer control module;

[0094] 510 - processor; 520 - memory; 530 - communication component; 540 - bus. DETAILED DESCRIPTION

[0095] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0096] In the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will appreciate that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit the difference. It should be noted that in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way. In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more.

[0097] It should be noted that the "at..." in the embodiments of the present application can be the instant when a certain situation occurs, or can be a period of time after a certain situation occurs, and the embodiments of the present application do not specifically limit this. In addition, the vehicle lateral control method provided in the embodiments of the present application is only used as an example, and the vehicle lateral control method can also include more or less content.

[0098] In order to clearly describe the technical solutions of the embodiments of the present application, some terms and technologies involved in the embodiments of the present application are briefly introduced below:

[0099] Linear Quadratic Regulator (LQR): An optimization control method that is applicable to linear systems and aims to minimize a quadratic cost function. The controller is designed by minimizing a quadratic performance index so that the system state and control input are optimally balanced.

[0100] Model Predictive Control (MPC): is a control method applicable to linear and nonlinear systems. It determines the current control input by solving a finite-time optimization problem at each control moment and can handle system constraints. MPC uses a system model to predict the behavior in the future and optimizes the control action based on this.

[0101] Sliding Mode Observer (SMO): A tool used in control systems to predict system states. It is suitable for nonlinear systems with uncertainty and external disturbances. The design of the sliding mode observer is based on the sliding mode control theory. By introducing a special "sliding mode", it can ensure that the system state prediction value quickly converges to the true value even in the presence of external disturbances or parameter uncertainties.

[0102] Sign function: usually denoted as sgn, used to extract the sign of a real number. For any real number (such as x), when x>0, sgn(x)=1; when x=0, sgn(x)=0; when x<0, sgn(x)=-1.

[0103] Front wheel lateral force: refers to the force at right angles to the driving direction that the front wheel tires of heavy vehicles are subjected to during driving. This force can be caused by factors such as wind force and road inclination, causing the wheels to deviate to the side.

[0104] In the process of intelligent driving of heavy-duty vehicles, lateral control can ensure that heavy-duty vehicles maintain an appropriate lateral position during driving. Due to the long body and large mass of heavy-duty vehicles, they are more susceptible to factors such as wind resistance and uneven roads during driving, so lateral control is needed to maintain the stability of the vehicle. In addition, lateral control can effectively prevent traffic accidents caused by vehicle deviation or loss of control, ensuring driving safety.

[0105] Existing lateral control methods usually follow these steps: First, based on the chassis dynamics model, the desired front wheel angle is calculated. This angle is the front wheel deflection angle required for the vehicle to maintain or change its lateral motion state (such as turning or keeping straight). Then, according to the preset proportional relationship, this desired front wheel angle is converted into the desired steering wheel angle and the desired motor torque. Finally, these control parameters are used to control the heavy vehicle laterally to achieve the desired driving trajectory.

[0106] However, although this method has achieved control over heavy vehicles to a certain extent, it still has some shortcomings, especially in terms of the accuracy of lateral control. Specifically, due to the long body and heavy load of heavy vehicles, electric hydraulic power steering systems are usually used, resulting in the relationship between the steering wheel angle and the front wheel angle of the vehicle cannot be simply expressed directly using a linear relationship. Therefore, the simple proportional conversion in the prior art is difficult to accurately reflect the actual needs of the vehicle's lateral movement, resulting in large deviations when the vehicle performs operations such as lane keeping and lane changing, thereby affecting driving safety and comfort.

[0107] Based on this, the embodiments of the present application propose a vehicle lateral control method, device, equipment, medium and product, which can be used in the field of intelligent driving technology, aiming to solve the above technical problems of the prior art. By fully considering the nonlinear relationship between the steering wheel angle and the front wheel angle of the vehicle, rather than directly converting the expected front wheel angle into the expected steering wheel angle and the expected motor torque through a linear proportional relationship, and according to the coordinated action of the cascaded outer controller and the inner controller, the lateral control of the heavy vehicle is achieved, thereby improving the accuracy of the lateral control of the heavy vehicle. Among them, the outer controller is used to calculate the expected front wheel angle of the vehicle according to the vehicle information, and the inner controller is used to calculate the expected steering wheel angle and the expected motor torque that are in a nonlinear relationship with the expected front wheel angle of the vehicle according to the expected front wheel angle of the vehicle and the vehicle information, thereby reducing the error between the expected steering wheel angle and the actual demand of the vehicle.

[0108] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0109] First, a hardware system applicable to a vehicle lateral control method in an embodiment of the present application is described in detail.

[0110] A vehicle lateral control method in an embodiment of the present application can be applied to an electric hydraulic steering system. Figure 1 This is a schematic diagram of the structure of the electric hydraulic steering system provided in the embodiment of the present application. Figure 1 As shown, the electric hydraulic steering system includes: a steering actuator 110, a hydraulic power module 120 and a wheel system 130. The steering actuator 110 includes: a steering wheel 111, a steering column 112, a first torsion bar 113, a reducer 114 and a motor 115. The hydraulic power module 120 includes: a second torsion bar 121, a screw rod 122, a sector gear 123, a steering drop arm 124 and a cylinder 125. The cylinder 125 includes a piston 126 and a cylinder body 127. The wheel system 130 includes: a front wheel 131 and a steering tie rod 132. The two ends of the steering column 112 are respectively connected to the steering wheel 111 and one end of the first torsion bar 113, the other end of the first torsion bar 113 and the motor 115 are connected to the reducer 114, the two ends of the second torsion bar 121 are respectively connected to the reducer 114 and one end of the screw rod 122, the other end of the screw rod 122 is connected to the piston 126, and the piston 126 is connected to the sector gear 123; the two ends of the steering arm 124 are respectively connected to the sector gear 123 and one end of the steering rod 132, and the other end of the steering rod 132 is connected to the front wheel 131.

[0111] Specifically, the embodiment of the present application realizes lateral control of a heavy vehicle by cooperating with a cascaded outer controller and an inner controller. The outer controller is used to calculate the expected front wheel steering angle of the heavy vehicle according to the dynamic model of the heavy vehicle. The inner controller can construct a simplified physical model of the electric hydraulic steering system of the heavy vehicle according to the structure and operating principle of the electric hydraulic power steering machine.

[0112] The working process of the electric hydraulic steering system includes: controlling the steering wheel 111 to rotate, driving the steering column 112 and the first torsion bar 113 to rotate synchronously, and transmitting the rotation to the second torsion bar 121 .

[0113] In the intelligent driving mode of heavy vehicles, the steering column 112 and the reducer 114 can also be regarded as a rigid body. The motor 115 can be used to drive the steering wheel 111. Specifically, the motor 115 is used to convert electrical energy into mechanical energy. When the motor 115 receives the steering instruction from the inner controller, it will rotate and generate corresponding torque. After the torque is amplified by the reducer 114, it can be used to drive the steering wheel 111 to rotate, thereby realizing steering assistance and increasing the torque transmitted to the second torsion bar 121.

[0114] The second torsion bar 121 connects the steering actuator 110 to the screw 122 in the hydraulic power module 120, and the screw 122 is connected to the piston 126, so that the rotational motion of the second torsion bar 121 can be converted into the translational motion of the piston 126 in the cylinder 125, that is, the piston 126 performs up and down translational motion as the second torsion bar 121 is twisted. In addition, the hydraulic power module 120 also includes an electric hydraulic circuit, which is composed of a symmetrical Wheatstone bridge, which is powered by a fixed displacement pump (electric pump 129), that is, in Figure 1 In the electric hydraulic circuit on the right side of the cylinder 125, an electric pump 129 and a plurality of symmetrical servo valves 128 are also included. By controlling the electric pump 129 and the plurality of servo valves 128 in the electric hydraulic circuit, the flow rate of the gas in the hydraulic circuit can be controlled, so that a pressure difference is generated between the upper and lower sides of the piston 126, thereby pushing the piston 126 to perform translational movement in the up and down directions.

[0115] like Figure 1 As shown, the left side of the piston 126 has teeth that can mesh with the sector gear 123, thereby driving the sector gear 123 to rotate. The sector gear 123 is connected to the front wheel 131 of the heavy vehicle through the steering drop arm 124 and the steering tie rod 132, thereby driving the front wheel 131 to rotate.

[0116] It can be seen from the working process of the above-mentioned electric hydraulic steering system that the total torque transmitted to the sector gear 123 includes: the torque generated by the second torsion bar 121, and the torque generated by the electric hydraulic circuit by generating a pressure difference on the upper and lower sides of the piston 126, thereby causing the piston 126 to move up and down to drive the sector gear 123 to rotate.

[0117] The total torque transmitted to the sector gear 123 can be used to resist the reaction force generated by the steering resistance torque of the heavy vehicle.

[0118] Next, a vehicle lateral control method provided in an embodiment of the present application is described in detail.

[0119] Figure 2 A schematic diagram of a vehicle lateral control method provided in an embodiment of the present application Figure 1 .

[0120] like Figure 2 As shown, the method includes:

[0121] S201. Obtain vehicle information and steering wheel angle change rate.

[0122] In the embodiment of the present application, the execution subject of a vehicle lateral control method can be an electronic control unit (ECU) in the vehicle, which can be a controller specially designed for vehicle lateral control or an existing steering control unit (SCU) in the vehicle, without specific limitation. The ECU can realize lateral control of the heavy vehicle by further controlling the cascaded outer controller and the inner controller.

[0123] The steering wheel angle change rate includes: the first-order differential and the second-order differential of the steering wheel angle. The vehicle information includes: basic vehicle body information, longitudinal speed information, actual position information and planned position information. The planned position information is the position information closest to the actual position information in the pre-generated planned path. The basic vehicle body information includes: wheel cornering stiffness, the distance from the vehicle center of mass to the front wheel, the distance from the vehicle center of mass to the rear wheel, vehicle mass, and vehicle moment of inertia.

[0124] Specifically, the steering wheel angle can be obtained through sensors in heavy vehicles, that is, the first-order differential and second-order differential of the steering wheel angle can be calculated in real time based on multiple steering wheel angles obtained historically. The basic body information can be pre-stored in the vehicle's ECU, and the longitudinal speed information and actual position information can be obtained through sensors in heavy vehicles.

[0125] S202, calling the outer controller to calculate the expected front wheel turning angle according to the planned position information, the actual position information, the basic vehicle body information, and the longitudinal speed information.

[0126] Specifically, the ECU can call the outer controller to calculate the expected front wheel turning angle according to the acquired planned position information, actual position information, vehicle body basic information, and longitudinal speed information through methods in the prior art, such as according to the chassis dynamics model.

[0127] S203, calling the inner controller to calculate the front wheel lateral force, and calculating the reaction torque applied to the sector gear according to the front wheel lateral force.

[0128] Specifically, in the wheel system, the relationship between the reaction torque applied to the sector gear and the steering resistance can be treated as a linear proportional relationship. Therefore, the ECU can call the inner controller to first calculate the front wheel lateral force of the heavy vehicle, and then calculate the reaction torque applied to the sector gear through the single-track vehicle dynamic model or the sliding film observer based on the front wheel lateral force.

[0129] S204, calling the inner controller to calculate the rotation angle of the second torsion bar according to the reaction torque, and calculating the expected motor torque according to the rotation angle of the second torsion bar and the steering wheel angle change rate.

[0130] Specifically, the ECU can further call the inner controller to calculate the rotation angle of the second torsion bar according to the reaction torque applied to the sector gear, thereby calculating the expected motor torque according to the rotation angle of the second torsion bar and the steering wheel angle change rate.

[0131] S205, calling the inner controller to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and calculating the desired steering wheel angle according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio.

[0132] In an embodiment of the present application, the preset reduction ratio is the reduction ratio between the screw and the sector gear, the expected steering wheel angle is the sum of the rotation angle of the second torsion bar and the screw rotation angle of the screw, and the screw rotation angle is the product of the expected sector gear angle and the preset reduction ratio.

[0133] Specifically, the ECU can calculate the product of the desired front wheel angle and the preset wheel transmission ratio by calling the inner controller to obtain the desired sector gear angle, and then calculate the desired steering wheel angle according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio. The calculation formula for the desired steering wheel angle is as follows:

[0134] θ s =a t +isg θ g =a t +i sg i gs δ f

[0135] Among them, θ s is the desired steering wheel angle, a t is the rotation angle of the second torsion bar, i sg is the preset reduction ratio between the screw and the sector gear, θ g is the desired sector gear angle, i gs is the preset wheel transmission ratio, δ f is the desired front wheel turning angle.

[0136] S206 , calling the inner controller to control the motor operation according to the expected motor torque, and calling the inner controller to control the steering wheel rotation according to the expected steering wheel angle.

[0137] Specifically, after calculating the expected steering wheel angle and the expected motor torque that are nonlinearly related to the expected front wheel angle of the vehicle, the ECU can call the inner controller to control the motor operation according to the expected motor torque, and at the same time control the steering wheel rotation according to the expected steering wheel angle by calling the inner controller to improve the accuracy of lateral control of heavy vehicles.

[0138] The present embodiment provides a vehicle lateral control method, the method comprising: obtaining vehicle information and steering wheel angle change rate, the steering wheel angle change rate comprising: first-order differential and second-order differential of the steering wheel angle, vehicle information comprising: vehicle body basic information, longitudinal speed information, actual position information and planned position information, the planned position information is the position information closest to the actual position information in the pre-generated planned path, the vehicle body basic information comprising: wheel lateral stiffness, the distance from the vehicle center of mass to the front wheel, the distance from the vehicle center of mass to the rear wheel, vehicle mass, and vehicle moment of inertia; calling an outer controller to calculate the desired front wheel angle according to the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information; calling an inner controller to calculate the front wheel lateral force, and calculating the force applied to the fan-shaped vehicle body according to the front wheel lateral force Reaction torque on the gear; calling the inner controller to calculate the rotation angle of the second torsion bar according to the reaction torque, and according to the rotation angle of the second torsion bar and the steering wheel angle change rate, calculate the desired motor torque; calling the inner controller to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, calculate the desired steering wheel angle, the preset reduction ratio is the reduction ratio between the screw and the sector gear, the desired steering wheel angle is the sum of the rotation angle of the second torsion bar and the screw rotation angle of the screw, the screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio; calling the inner controller to control the motor operation according to the desired motor torque, and calling the inner controller to control the steering wheel rotation according to the desired steering wheel angle.

[0139] The following technical effects are achieved: the outer controller calculates the expected front wheel angle of the vehicle according to the vehicle information, and then the inner controller calculates the expected steering wheel angle and the expected motor torque that are nonlinearly related to the expected front wheel angle of the vehicle according to the expected front wheel angle and the vehicle information, thereby reducing the error between the expected steering wheel angle and the actual demand of the vehicle; the motor operation is controlled according to the expected motor torque by calling the inner controller, and the steering wheel rotation is controlled according to the expected steering wheel angle by calling the inner controller, thereby improving the accuracy of lateral control of heavy vehicles.

[0140] Figure 3 A schematic diagram of a vehicle lateral control method provided in an embodiment of the present application Figure 2 In one possible example, Figure 3 As shown, in this embodiment Figure 2 Based on the embodiment, how to calculate the expected front wheel angle and the expected motor torque is described in detail. Figure 3 As shown, the method includes:

[0141] S301. Obtain vehicle information and steering wheel angle change rate.

[0142] S301 is similar to S201 and will not be described in detail in this embodiment.

[0143] S302: Determine a position error and a direction error according to the planned position information and the actual position information, and generate a position error change rate and a direction error change rate according to the position errors at multiple moments and the direction errors at multiple moments.

[0144] Specifically, the outer controller can realize the trajectory tracking and lateral control of the heavy vehicle based on the error tracking. Specifically, calling the outer controller to calculate the expected front wheel turning angle according to the chassis dynamics model includes: firstly determining the position error and direction error according to the planned position information and the actual position information. The specific calculation formula is:

[0145]

[0146]

[0147] Among them, e y is the position error between the actual position of the heavy vehicle and the planned position. The planned position refers to the position in the pre-generated planned path of the heavy vehicle that is closest to the actual position of the heavy vehicle. dmin is the orientation of the planned position, x is the horizontal coordinate of the actual position of the heavy vehicle, y is the vertical coordinate of the actual position of the heavy vehicle, and x dmin is the horizontal coordinate of the planned position, y dmin is the ordinate of the planned location, is the directional error between the actual position and the planned position of the heavy vehicle, k r is the curvature of the planned path at the planned position.

[0148] Then, according to the position error e at multiple moments y and the directional error at multiple moments Generates the rate of change of position error and direction error change rate

[0149] S303, inputting the basic vehicle body information, longitudinal speed information, position error, direction error, position error change rate and direction error change rate into the state space equation of the vehicle to calculate the expected front wheel turning angle δ f .

[0150] Specifically, the state space equation of the vehicle is:

[0151]

[0152] Among them, C af is the front wheel cornering stiffness, C aris the rear wheel cornering stiffness, m is the vehicle mass, i.e. the vehicle mass of a heavy vehicle, a is the distance from the vehicle center of mass to the front wheel, b is the distance from the vehicle center of mass to the rear wheel, V x is the longitudinal velocity of the heavy vehicle, I is the moment of inertia of the vehicle, is the yaw angle of the actual position of the heavy vehicle, is the actual yaw rate. According to the state space equation of the vehicle, the desired front wheel steering angle δ can be calculated by LQR or MPC algorithm. f .

[0153] S304: Construct an error vector of a synovial membrane observer.

[0154] Specifically, the ECU can predict the front wheel lateral force F according to the basic principle of the sliding film observer. yf First, the inner controller is called to construct the error vector of the synovial observer Error Vector Included: yaw rate error Front wheel lateral force error and rear wheel lateral force error Error Vector As shown below:

[0155]

[0156] in, is the actual yaw angular velocity, To predict the yaw rate, F yf is the lateral force of the front wheel, is the predicted front wheel lateral force, F yr is the rear wheel lateral force, is the predicted rear wheel lateral force.

[0157] S305 , iteratively training the synovial observer according to the error vector to obtain multiple gains of the synovial observer.

[0158] In the embodiment of the present application, in order to construct a synovial observer, the front wheel lateral force F yf The rate of change of the rear wheel lateral force F yr The rate of change is considered to be 0, that is in, is the front wheel lateral force F yf The rate of change, is the rear wheel lateral force F yr The rate of change. R 3 represents the predicted state, due to the yaw rate and lateral acceleration a y It can be detected by the sensor, so that the measurement output of the synovial observer can be

[0159] The formula for predicting the lateral force of the front wheel by the sliding film observer is as follows:

[0160]

[0161] in, To predict the yaw rate, I is the vehicle moment of inertia, a is the distance from the vehicle center of mass to the front wheel, b is the distance from the vehicle center of mass to the rear wheel, ρ1 to ρ6 are the six gains of the sliding film observer, is the predicted front wheel lateral force, is the predicted rate of change of the front wheel lateral force, is the predicted rear wheel lateral force, is the predicted rate of change of the rear wheel lateral force, is the actual yaw angular velocity, a y is the actual lateral acceleration, is the predicted lateral acceleration, and sgn is a function with positive and negative signs.

[0162] According to the error vector Iteratively train the synovial observer so that the error vector It converges to 0, thus obtaining the six gains ρ1 to ρ6 of the synovial observer.

[0163] The constraints of the six gains ρ1 to ρ6 in the embodiment of the present application are as follows:

[0164]

[0165] ρ3=-ρ5>0

[0166]

[0167] By continuously adjusting the six gains ρ1 to ρ6 of the synovial observer, the error vector Tends to 0. That is, through multiple iterations and continuous adjustments, the predicted state quickly converges to the real state, even if the predicted yaw angular velocity in the predicted state The actual yaw rate Consistent, predicted front wheel lateral force The actual front wheel lateral force F yf Consistent, predicted rear wheel lateral force The actual rear wheel lateral force F yr Consistent.

[0168] The sgn function is a sign function, specifically a logic function (sigmoid function), and the six gains ρ1 to ρ6 of the adjusted synovial observer can be respectively: ρ1=2.7, ρ2=0, ρ3=800000, ρ4=87000, ρ5=-800000, ρ6=164208.

[0169] Furthermore, the error vector and Substituting into the above formula, we get:

[0170]

[0171]

[0172]

[0173] in, is the lateral acceleration error. By making the yaw rate error Front wheel lateral force error and rear wheel lateral force error The rate of change of is 0, and the synovial observer is iteratively trained to obtain the 6 gains ρ1 to ρ6 of the synovial observer.

[0174] S306 , predicting the front wheel lateral force by using multiple gains of the synovial observer.

[0175] Specifically, after obtaining the error vector After the six gains ρ1 to ρ6 of the synovial observer corresponding to time 0 converge, the front wheel lateral force can be predicted according to the formula for predicting the front wheel lateral force of the synovial observer.

[0176] Furthermore, in a possible implementation, the lateral acceleration, the distance from the vehicle center of mass to the front wheel, the distance from the vehicle center of mass to the rear wheel, the vehicle mass, and the vehicle moment of inertia are input into a monorail vehicle dynamic model, and the front wheel lateral force can also be obtained.

[0177] Specifically, in the single-track vehicle dynamic model, the tire lateral force model is as follows:

[0178] ma y =F yf +F yr

[0179]

[0180] Where m is the vehicle mass, a y is the lateral acceleration, is the vehicle's moment of inertia, a is the distance from the vehicle's center of mass to the front wheel, and b is the distance from the vehicle's center of mass to the rear wheel.

[0181] S307: Obtain the wheel axle distance of the vehicle.

[0182] Specifically, after calculating the front wheel lateral force, the ECU can further obtain the axle distance of the heavy vehicle, that is, the distance between the wheel and the axle center of the heavy vehicle, to calculate the reaction torque exerted on the sector gear by the front wheel lateral force.

[0183] S308: Calculate the product of the front wheel lateral force, the wheel axle distance and the preset proportional coefficient to obtain the reaction torque.

[0184] Specifically, the calculation formula for the reaction torque exerted by the lateral force of the front wheel on the sector gear is as follows:

[0185] τ p =F yf ×d×c

[0186] Among them, τ p is the reaction torque, d is the wheel axle distance, and c is the preset proportional coefficient.

[0187] S309: Obtain system information of the electric hydraulic steering system.

[0188] In the embodiment of the present application, the system information includes: the piston side area A of the piston P , radius R of sector gear sg , Internal structural parameters of steering actuator C n , Flow leakage coefficient K between cylinder and piston le , the pressure difference ΔP between the upper and lower chambers of the cylinder, the preset reduction ratio i sg , the stiffness of the second torsion bar K t .

[0189] After calculating the reaction torque exerted by the lateral force of the front wheel on the sector gear, the ECU can calculate the rotation angle of the second torsion bar according to the reaction torque. First, the system information of the electric hydraulic steering system is further obtained to calculate the rotation angle of the second torsion bar according to the system information and the reaction torque.

[0190] S310: Input the system information and the reaction torque into a second torsion bar angle calculation model to obtain a rotation angle of the second torsion bar.

[0191] In this embodiment, the formula of the second torsion bar angle calculation model is as follows:

[0192]

[0193] sgn(ΔP) is the sign of ΔP, τ P is the reaction torque, A Pis the piston side area of ​​the piston, R sg is the radius of the sector gear, C n is the internal structural parameter of the steering actuator, K le is the flow leakage coefficient between the cylinder and the piston, ΔP is the pressure difference between the upper and lower air chambers of the cylinder, i sg is the preset reduction ratio, K t is the stiffness of the second torsion bar, a t is the rotation angle of the second torsion bar. By solving the formula of the second torsion bar angle calculation model, the rotation angle a of the second torsion bar can be obtained. t .

[0194] Specifically, the motion model of the hydraulic power module can be equivalently obtained according to the actual structure of the hydraulic power module. The calculation formula of the motion model of the hydraulic power module is as follows:

[0195]

[0196] Among them, J r is the equivalent inertia between the screw and the sector gear, is the preset value, θ g is the desired sector gear angle, f vr is the equivalent damping coefficient between the screw and the sector gear, f fr is the nonlinear friction coefficient during vehicle steering, τ t is the torque of the second torsion bar, F hps F is the thrust of the piston caused by the gas pressure difference in the cylinders on both sides of the piston. hps The calculation formula is as follows:

[0197] F hps =A P ΔP=A P (P U -P D );

[0198] Among them, P U is the gas pressure in the upper air chamber above the piston, P D is the gas pressure of the lower air chamber below the piston. The equivalent inertia J between the screw and the sector gear r , the equivalent damping coefficient f between the screw and the sector gear vr , and the nonlinear friction coefficient f during vehicle steering fr Ignore them all and set F hps Substituting the calculation formula into the calculation formula of the motion model of the hydraulic power module, we can get:

[0199] i sg K t a t +A P Rsg ΔP=τ P ;

[0200] Then the rotation angle a of the second torsion bar is t Substituting the relationship between the pressure difference ΔP into the above formula, the formula for calculating the second torsion bar angle can be obtained. Among them, the rotation angle a of the second torsion bar t The relationship between the pressure difference ΔP is as follows:

[0201]

[0202] Among them, C n is the internal structural parameter of the steering actuator and can be a preset value.

[0203] S311 . Calculate the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar as the torque of the second torsion bar.

[0204] Specifically, the torque τ of the second torsion bar t The calculation formula is:

[0205] τ t =K t a t ;

[0206] Among them, τ t is the torque of the second torsion bar, K t is the stiffness of the second torsion bar, a t is the rotation angle of the second torsion bar.

[0207] S312: Obtain steering actuator information.

[0208] In this embodiment, the steering actuator information includes the equivalent inertia J of the steering actuator. s , damping coefficient f of steering actuator vs , Friction coefficient f of steering actuator sf In order to calculate the expected motor torque, the steering actuator information can be further obtained.

[0209] S313: input the steering actuator information, the torque of the second torsion bar and the steering wheel angle change rate into a torque calculation model to obtain the expected motor torque.

[0210] In this embodiment, the torque calculation model is as follows:

[0211]

[0212] and are the first and second order differentials of the steering wheel angle, τ s is the desired motor torque, τ tis the torque of the second torsion bar.

[0213] S314, calling the inner controller to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and calculating the desired steering wheel angle according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio.

[0214] S315: Calling the inner controller to control the motor operation according to the expected motor torque, and calling the inner controller to control the steering wheel rotation according to the expected steering wheel angle.

[0215] S314-S315 are similar to S205-S206 and will not be described in detail in this embodiment.

[0216] A vehicle lateral control method provided by an embodiment of the present application constructs an error vector of a synovial observer, thereby iteratively training the synovial observer according to the error vector, and obtaining the front wheel lateral force of the heavy vehicle when the error vector converges to 0, thereby improving the accuracy of the calculated front wheel lateral force, thereby improving the accuracy of the expected motor torque and the expected steering wheel angle calculated according to the front wheel lateral force, and ultimately improving the accuracy of the lateral control of the heavy vehicle; by establishing a second torsion bar angle calculation model including the pressure difference between the upper air chamber and the lower air chamber of the cylinder, the nonlinear relationship between the electric hydraulic circuit and the rotation angle of the second torsion bar is fully considered when calculating the rotation angle of the second torsion bar, thereby improving the calculation accuracy of the rotation angle of the second torsion bar, thereby improving the accuracy of the expected motor torque and the expected steering wheel angle calculated according to the rotation angle of the second torsion bar; by inputting lateral acceleration, the distance from the center of mass of the vehicle to the front wheel, the distance from the center of mass of the vehicle to the rear wheel, the vehicle mass, and the vehicle moment of inertia into a monorail vehicle dynamic model, the front wheel lateral force is calculated, and another method for calculating the front wheel lateral force is provided.

[0217] The embodiment of the present invention can divide the electronic device or the main control device into functional modules according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present invention is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0218] Figure 4A schematic diagram of the structure of a vehicle lateral control device provided in an embodiment of the present application. The vehicle lateral control device is applied to an electric hydraulic steering system, which includes: a steering actuator, a hydraulic power module and a wheel system, the steering actuator includes: a steering wheel, a steering column, a first torsion bar, a reducer and a motor, the hydraulic power module includes: a second torsion bar, a screw rod, a sector gear, a steering drop arm and a cylinder, the cylinder includes a piston and a cylinder body, the wheel system includes: a front wheel and a steering tie rod, the two ends of the steering column are respectively connected to the steering wheel and one end of the first torsion bar, the other end of the first torsion bar and the motor are both connected to the reducer, the two ends of the second torsion bar are respectively connected to the reducer and one end of the screw rod, the other end of the screw rod is connected to the piston, and the piston is connected to the sector gear; the two ends of the steering drop arm are respectively connected to the sector gear and one end of the steering tie rod, and the other end of the steering tie rod is connected to the front wheel.

[0219] like Figure 4 As shown, the vehicle lateral control device includes: an acquisition module 410, an outer layer control module 420, a first inner layer control module 430, a second inner layer control module 440, a third inner layer control module 450, and a fourth inner layer control module 460;

[0220] The acquisition module 410 is used to acquire vehicle information and steering wheel angle change rate, wherein the steering wheel angle change rate includes: first-order differential and second-order differential of the steering wheel angle, the vehicle information includes: basic vehicle body information, longitudinal speed information, actual position information and planned position information, wherein the planned position information is the position information closest to the actual position information in the pre-generated planned path, and the basic vehicle body information includes: wheel cornering stiffness, distance from the vehicle center of mass to the front wheel, distance from the vehicle center of mass to the rear wheel, vehicle mass, and vehicle moment of inertia;

[0221] The outer control module 420 is used to call the outer controller to calculate the expected front wheel turning angle according to the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information;

[0222] A first inner layer control module 430, used for calling the inner layer controller to calculate the front wheel lateral force, and calculating the reaction torque applied to the sector gear according to the front wheel lateral force;

[0223] The second inner control module 440 is used to call the inner controller to calculate the rotation angle of the second torsion bar according to the reaction torque, and calculate the expected motor torque according to the rotation angle of the second torsion bar and the steering wheel angle change rate;

[0224] The third inner layer control module 450 is used to call the inner layer controller to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and calculate the desired steering wheel angle according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio. The preset reduction ratio is the reduction ratio between the screw and the sector gear. The desired steering wheel angle is the sum of the rotation angle of the second torsion bar and the screw rotation angle of the screw. The screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio.

[0225] The fourth inner control module 460 is used to call the inner controller to control the motor operation according to the expected motor torque, and call the inner controller to control the steering wheel rotation according to the expected steering wheel angle.

[0226] In one possible design, the outer control module 420 includes: an error change rate module and a first input module;

[0227] An error change rate module is used to determine the position error and the direction error according to the planned position information and the actual position information, and generate the position error change rate and the direction error change rate according to the position errors at multiple moments and the direction errors at multiple moments;

[0228] The first input module is used to input vehicle body basic information, longitudinal speed information, position error, direction error, position error change rate and direction error change rate into the state space equation of the vehicle to calculate the expected front wheel turning angle.

[0229] In one possible design, the first inner control module 430 includes: a module for calculating the front wheel lateral force;

[0230] The module for calculating the lateral force of the front wheel is used to input the lateral acceleration, the distance from the center of mass of the vehicle to the front wheel, the distance from the center of mass of the vehicle to the rear wheel, the vehicle mass, and the vehicle moment of inertia into the monorail vehicle dynamic model to obtain the lateral force of the front wheel.

[0231] In a possible design, the module for calculating the front wheel lateral force further includes: a construction module, an iteration module and a prediction module;

[0232] A construction module is used to construct an error vector of a sliding film observer, wherein the error vector includes: a yaw rate error, a front wheel lateral force error, and a rear wheel lateral force error;

[0233] An iteration module, used for iteratively training the synovial observer according to the error vector to obtain multiple gains of the synovial observer;

[0234] A prediction module, for predicting the front wheel lateral force through a plurality of gains of a sliding film observer;

[0235] The formula for predicting the lateral force of the front wheel by the sliding film observer is as follows:

[0236]

[0237] in, To predict the yaw rate, I is the vehicle moment of inertia, a is the distance from the vehicle center of mass to the front wheel, b is the distance from the vehicle center of mass to the rear wheel, ρ1 to ρ6 are the six gains of the sliding film observer, is the predicted front wheel lateral force, is the predicted rate of change of the front wheel lateral force, is the predicted rear wheel lateral force, is the predicted rate of change of the rear wheel lateral force, is the actual yaw angular velocity, a y is the actual lateral acceleration, is the predicted lateral acceleration, and sgn is a function with positive and negative signs.

[0238] In a possible design, the first inner layer control module 430 further includes: an axle distance module and a first product module:

[0239] The axle distance module is used to obtain the axle distance of the vehicle. The axle distance is the distance between the wheel and the axle center.

[0240] The first product module is used to calculate the product of the front wheel lateral force, the wheel axle distance and a preset proportional coefficient to obtain a reaction torque.

[0241] In one possible design, the second inner layer control module 440 includes: a system information acquisition module and a second input module;

[0242] The system information acquisition module is used to acquire the system information of the electric hydraulic steering system. The system information includes: the piston side area A of the piston P , radius R of sector gear sg , Internal structural parameters of steering actuator C n , Flow leakage coefficient K between cylinder and piston le , the pressure difference ΔP between the upper and lower chambers of the cylinder, the preset reduction ratio i sg , the stiffness of the second torsion bar K t ;

[0243] A second input module, used for inputting system information and reaction torque into a second torsion bar angle calculation model to obtain a rotation angle of the second torsion bar;

[0244] Among them, the second torsion bar angle calculation model is as follows:

[0245]

[0246] sgn(ΔP) is the sign of ΔP, τ Pis the reaction torque, a t is the rotation angle of the second torsion bar.

[0247] In a possible design, the second inner layer control module 440 further includes: a second product module, an actuator information acquisition module, and a third input module;

[0248] A second product module, used for calculating the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar as the torque of the second torsion bar;

[0249] The actuator information acquisition module is used to acquire the steering actuator information, including the equivalent inertia J of the steering actuator. s , damping coefficient f of steering actuator vs , Friction coefficient f of steering actuator sf ;

[0250] A third input module is used to input the steering actuator information, the torque of the second torsion bar and the steering wheel angle change rate into the torque calculation model to obtain the expected motor torque;

[0251] The torque calculation model is as follows:

[0252]

[0253] and are the first and second order differentials of the steering wheel angle, τ s is the desired motor torque, τ t is the torque of the second torsion bar.

[0254] A vehicle lateral control device provided in this embodiment can execute a vehicle lateral control method of the above embodiment, and its implementation principle and technical effect are similar, so this embodiment will not be repeated here.

[0255] In the specific implementation of the aforementioned vehicle lateral control device, each module can be implemented as a processor, and the processor can execute computer-executable instructions stored in the memory, so that the processor executes the aforementioned vehicle lateral control method.

[0256] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 5 As shown, the electronic device includes: at least one processor 510 and a memory 520. The electronic device also includes a communication component 530. The processor 510, the memory 520 and the communication component 530 are connected via a bus 540.

[0257] In a specific implementation process, at least one processor 510 executes the computer-executable instructions stored in the memory 520, so that at least one processor 510 executes a vehicle lateral control method executed by the electronic device side as described above.

[0258] The specific implementation process of the processor 510 can be found in the above method embodiment, and its implementation principle and technical effect are similar, so this embodiment will not be repeated here.

[0259] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the invention may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0260] The memory may include a high-speed RAM memory, and may also include a non-volatile storage NVM, such as at least one disk storage.

[0261] The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus in the drawings of the present application is not limited to only one bus or one type of bus.

[0262] The above-mentioned functions implemented by the electronic device and the main control device introduce the scheme provided by the embodiment of the present invention. It can be understood that in order to implement the above-mentioned functions, the electronic device or the main control device includes a hardware structure and / or software module corresponding to the execution of each function. In combination with the units and algorithm steps of each example described in the embodiment disclosed in the embodiment of the present invention, the embodiment of the present invention can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the technical solution of the embodiment of the present invention.

[0263] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, it is used to implement the above-mentioned vehicle lateral control method.

[0264] The above-mentioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special-purpose computer.

[0265] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (Application Specific Integrated Circuits, referred to as: ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in an electronic device or a main control device.

[0266] The present application also provides a computer program product, which includes a computer program. The computer program is stored in a readable storage medium. At least one processor of an electronic device can read the computer program from the readable storage medium. At least one processor executes the computer program so that the electronic device executes the solution provided in any of the above embodiments.

[0267] Those skilled in the art can understand that all or part of the steps of the above method embodiments can be completed by hardware related to program instructions. The above program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above method embodiments are executed; and the above storage medium includes: ROM, RAM, disk or optical disk and other media that can store program codes.

[0268] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments, and the above embodiments are only used to illustrate the technical solution of the present application rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A vehicle lateral control method, characterized in that: Applied to an electric hydraulic steering system, the electric hydraulic steering system comprises: a steering actuator, a hydraulic power module and a wheel system, the steering actuator comprises: a steering wheel, a steering column, a first torsion bar, a reducer and a motor, the hydraulic power module comprises: a second torsion bar, a screw rod, a sector gear, a steering drop arm and a cylinder, the cylinder comprises a piston and a cylinder body, the wheel system comprises: a front wheel and a steering tie rod, the two ends of the steering column are respectively connected to the steering wheel and one end of the first torsion bar, the other end of the first torsion bar and the motor are both connected to the reducer, the two ends of the second torsion bar are respectively connected to the reducer and one end of the screw rod, the other end of the screw rod is connected to the piston, and the piston is connected to the sector gear; the two ends of the steering drop arm are respectively connected to the sector gear and one end of the steering tie rod, and the other end of the steering tie rod is connected to the front wheel; The method comprises: Acquire vehicle information and steering wheel angle change rate, wherein the steering wheel angle change rate includes: first-order differential and second-order differential of the steering wheel angle, the vehicle information includes: basic vehicle body information, longitudinal speed information, actual position information and planned position information, wherein the planned position information is the position information closest to the actual position information in the pre-generated planned path, and the basic vehicle body information includes: wheel cornering stiffness, distance from the vehicle center of mass to the front wheel, distance from the vehicle center of mass to the rear wheel, vehicle mass, and vehicle moment of inertia; Invoking an outer controller to calculate an expected front wheel turning angle according to the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information; Invoke the inner controller to calculate the lateral force of the front wheel, and calculate the reaction torque applied to the sector gear according to the lateral force of the front wheel; Invoke an inner controller to calculate a rotation angle of the second torsion bar according to the reaction torque, and calculate a desired motor torque according to the rotation angle of the second torsion bar and a steering wheel angle change rate; The inner controller is called to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and the desired steering wheel angle is calculated according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, wherein the preset reduction ratio is the reduction ratio between the screw and the sector gear, and the desired steering wheel angle is the sum of the rotation angle of the second torsion bar and the screw rotation angle of the screw, and the screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio; The inner controller is called to control the operation of the motor according to the desired motor torque, and the inner controller is called to control the rotation of the steering wheel according to the desired steering wheel angle.

2. The method according to claim 1, characterized in that The calculating the expected front wheel turning angle according to the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information includes: Determine a position error and a direction error according to the planned position information and the actual position information, and generate a position error change rate and a direction error change rate according to the position error at multiple moments and the direction error at multiple moments; The vehicle body basic information, the longitudinal speed information, the position error, the direction error, the position error change rate and the direction error change rate are input into the state space equation of the vehicle to calculate the expected front wheel turning angle.

3. The method according to claim 1, characterized in that: The vehicle information also includes: lateral acceleration, and the calculation of the front wheel lateral force includes: The lateral acceleration, the distance from the vehicle center of mass to the front wheel, the distance from the vehicle center of mass to the rear wheel, the vehicle mass, and the vehicle moment of inertia are input into a monorail vehicle dynamic model to obtain the front wheel lateral force.

4. The method according to claim 1, characterized in that: The calculating of the front wheel lateral force comprises: Constructing an error vector of a sliding film observer, wherein the error vector includes: a yaw rate error, a front wheel lateral force error, and a rear wheel lateral force error; Iteratively training a synovial observer according to the error vector to obtain a plurality of gains of the synovial observer; predicting the front wheel lateral force by using a plurality of gains of the synovial observer; The formula for predicting the front wheel lateral force by the synovial observer is as follows: Among them, the To predict the yaw rate, I is the moment of inertia of the vehicle, a is the distance from the center of mass of the vehicle to the front wheel, b is the distance from the center of mass of the vehicle to the rear wheel, ρ1 to ρ6 are the six gains of the sliding film observer, is the predicted front wheel lateral force, is the predicted rate of change of the front wheel lateral force, To predict the rear wheel lateral force, is the predicted rate of change of the rear wheel lateral force, is the actual yaw angular velocity, and a y is the actual lateral acceleration, is the predicted lateral acceleration, and sgn is a function of positive and negative signs.

5. The method according to any one of claims 1 to 4, characterized in that The step of calculating the reaction torque applied to the sector gear according to the front wheel lateral force comprises: Obtaining the axle distance of the vehicle, where the axle distance is the distance between the wheel and the axle center; The reaction torque is obtained by calculating the product of the front wheel lateral force, the wheel axle distance and a preset proportional coefficient.

6. The method according to any one of claims 1 to 4, characterized in that The step of calculating the rotation angle of the second torsion bar according to the reaction torque comprises: Obtain system information of the electric hydraulic steering system, the system information including: the piston side area A of the piston P , the radius R of the sector gear sg , the internal structural parameters C of the steering actuator n , the flow leakage coefficient K between the cylinder and the piston le , the pressure difference ΔP between the upper air chamber and the lower air chamber of the cylinder, the preset reduction ratio i sg , the stiffness K of the second torsion bar t ; Inputting the system information and the reaction torque into a second torsion bar angle calculation model to obtain a rotation angle of the second torsion bar; Wherein, the second torsion bar angle calculation model is as follows: The sgn(ΔP) is the sign of the ΔP, the τ P is the reaction torque, the a t is the rotation angle of the second torsion bar.

7. The method according to claim 6, characterized in that The step of calculating the expected motor torque according to the rotation angle of the second torsion bar and the steering wheel angle change rate includes: calculating the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar as the torque of the second torsion bar; Obtain steering actuator information, the steering actuator information includes the equivalent inertia J of the steering actuator s , the damping coefficient f of the steering actuator vs , the friction coefficient f of the steering actuator sf ; Inputting the steering actuator information, the torque of the second torsion bar and the steering wheel angle change rate into a torque calculation model to obtain the expected motor torque; Wherein, the torque calculation model is as follows: Said and stated are the first-order differential and second-order differential of the steering wheel angle respectively, and the τ s is the desired motor torque, the τ t is the torque of the second torsion bar.

8. A vehicle lateral control device, characterized in that: Applied to an electric hydraulic steering system, the electric hydraulic steering system comprises: a steering actuator, a hydraulic power module and a wheel system, the steering actuator comprises: a steering wheel, a steering column, a first torsion bar, a reducer and a motor, the hydraulic power module comprises: a second torsion bar, a screw rod, a sector gear, a steering drop arm and a cylinder, the cylinder comprises a piston and a cylinder body, the wheel system comprises: a front wheel and a steering tie rod, the two ends of the steering column are respectively connected to the steering wheel and one end of the first torsion bar, the other end of the first torsion bar and the motor are both connected to the reducer, the two ends of the second torsion bar are respectively connected to the reducer and one end of the screw rod, the other end of the screw rod is connected to the piston, and the piston is connected to the sector gear; the two ends of the steering drop arm are respectively connected to the sector gear and one end of the steering tie rod, and the other end of the steering tie rod is connected to the front wheel; The device comprises: an acquisition module, for acquiring vehicle information and a steering wheel angle change rate, wherein the steering wheel angle change rate includes: a first-order differential and a second-order differential of the steering wheel angle, the vehicle information includes: basic vehicle body information, longitudinal speed information, actual position information and planned position information, wherein the planned position information is the position information closest to the actual position information in a pre-generated planned path, and the basic vehicle body information includes: wheel cornering stiffness, a distance from the vehicle center of mass to the front wheel, a distance from the vehicle center of mass to the rear wheel, vehicle mass, and vehicle moment of inertia; An outer control module, used for calling an outer controller to calculate a desired front wheel turning angle according to the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information; a first inner layer control module, used for calling the inner layer controller to calculate the front wheel lateral force, and calculating the reaction torque applied to the sector gear according to the front wheel lateral force; A second inner control module is used to call the inner controller to calculate the rotation angle of the second torsion bar according to the reaction torque, and calculate the expected motor torque according to the rotation angle of the second torsion bar and the steering wheel angle change rate; a third inner control module, configured to call the inner controller to calculate the product of the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle, and to calculate the desired steering wheel angle according to the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, wherein the preset reduction ratio is the reduction ratio between the screw and the sector gear, the desired steering wheel angle is the sum of the rotation angle of the second torsion bar and the screw rotation angle of the screw, and the screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio; The fourth inner control module is used to call the inner controller to control the operation of the motor according to the expected motor torque, and call the inner controller to control the rotation of the steering wheel according to the expected steering wheel angle.

9. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the vehicle lateral control method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the vehicle lateral control method according to any one of claims 1 to 7.

11. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the vehicle lateral control method according to any one of claims 1 to 7 is implemented.

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