Vehicle lateral control methods, devices, equipment, media and products

Abstract

This application provides a vehicle lateral control method, device, equipment, medium, and product, relating to the field of intelligent driving technology. The method includes: acquiring vehicle information and steering wheel angle change rate; calling an outer controller to calculate the desired front wheel angle based on planned position information, actual position information, vehicle body basic information, and longitudinal speed information; calling an inner controller to calculate the front wheel lateral force, and calculating the reaction torque applied to the sector gear based on the front wheel lateral force, thereby calculating the rotation angle of the second torsion bar, and calculating the desired motor torque and desired steering wheel angle based on the rotation angle of the second torsion bar and the steering wheel angle change rate; finally, calling the inner controller to control the motor operation based on the desired motor torque, and controlling the steering wheel rotation based on the desired steering wheel angle. This method improves the accuracy of lateral control for heavy vehicles by fully considering the nonlinear relationship between the vehicle's steering wheel angle and front wheel angle.

Description

Technical Field

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

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

[0003] In the prior art, the lateral control method for heavy vehicles typically includes the following steps: First, the desired front wheel steering angle is calculated based on the chassis dynamics model; then, the desired front wheel steering angle is converted into the desired steering wheel angle and the desired motor torque through a preset proportional relationship; finally, the heavy vehicle is laterally controlled based on the desired steering wheel angle and the desired motor torque.

[0004] However, existing lateral control methods for heavy vehicles suffer from poor lateral control accuracy. Summary of the Invention

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

[0006] In a first aspect, this application provides a vehicle lateral control method applied to an electro-hydraulic steering system. The electro-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, a sector gear, a steering 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. The other end of the screw is connected to the piston, and the piston is connected to the sector gear. The two ends of the steering 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.

[0007] The method includes:

[0008] The system acquires vehicle information and steering wheel angle change rate, which includes the first and second derivatives of the steering wheel angle. Vehicle information includes basic vehicle body information, longitudinal velocity 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 the vehicle's center of gravity to the front wheel, distance from the vehicle's center of gravity to the rear wheel, vehicle mass, and vehicle moment of inertia.

[0009] The outer controller is invoked to calculate the desired front wheel steering angle based on the planned position information, actual position information, vehicle body basic information, and longitudinal speed information;

[0010] The inner controller is invoked to calculate the lateral force on the front wheels, and the reaction torque applied to the sector gear is calculated based on the lateral force on the front wheels.

[0011] The inner controller is invoked to calculate the rotation angle of the second torsion bar based on the reaction torque, and the desired motor torque is calculated based on the rotation angle of the second torsion bar and the rate of change of the steering wheel angle.

[0012] The inner controller is called to calculate the desired front wheel angle by multiplying the desired front wheel angle by the preset wheel transmission ratio. The desired sector gear angle is obtained by multiplying the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio. The desired steering wheel angle is calculated based on 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 invoked to control the motor operation based on the desired motor torque, and the inner controller is invoked to control the steering wheel rotation based on the desired steering wheel angle.

[0014] In one possible design, the desired front wheel steering angle is calculated based on the planned location information, actual location information, vehicle body basic information, and longitudinal velocity information, including:

[0015] The position error and direction error are determined based on the planned position information and the actual position information, and the position error change rate and direction error change rate are generated based on the position error at multiple times and the direction error at multiple times.

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

[0017] In one possible design, vehicle information also includes: lateral acceleration, and calculation of front wheel lateral forces, including:

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

[0019] In one possible design, the calculation of the front wheel lateral forces includes:

[0020] Construct the error vector of the synovial observer, which includes: yaw rate error, front wheel lateral force error, and rear wheel lateral force error;

[0021] The slug observer is iteratively trained based on the error vector to obtain multiple gains of the slug observer.

[0022] Predicting front wheel lateral forces using multiple gains from a synovial observer;

[0023] The formula for predicting the lateral force of the front wheel using a synovial membrane observer is as follows:

[0024]

[0025] in, To predict yaw rate, I represents the vehicle's moment of inertia, a is the distance from the vehicle's center of mass to the front wheel, b is the distance from the vehicle's center of mass to the rear wheel, and ρ1 to ρ6 are the six gains of the slicker observer. For the predicted front wheel lateral force, The predicted rate of change of the front wheel lateral force. For the predicted rear wheel lateral force, The predicted rate of change of the rear wheel lateral force. a is the actual yaw rate. y It is the actual lateral acceleration. It predicts lateral acceleration, and sgn is a function that takes the positive or negative sign.

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

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

[0028] The reaction torque is obtained by multiplying the front wheel lateral force, the wheel-axle distance, and the preset proportional coefficient.

[0029] In one possible design, the rotation angle of the second torsion bar is calculated based on the reaction torque, including:

[0030] Obtain system information for the electro-hydraulic steering system, including: piston side surface area A. P The radius R of the sector gear sg 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 and lower chambers of the cylinder, and the preset reduction ratio i sg The stiffness K of the second torsion bar t ;

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

[0032] The calculation model for the second torsion bar angle is as follows:

[0033]

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

[0035] In one possible design, the desired motor torque is calculated based on the rotation angle of the second torsion bar and the rate of change of the steering wheel angle, including:

[0036] Calculate the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar, and use it as the torque of the second torsion bar;

[0037] Obtain steering actuator information, including 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 ;

[0038] The steering actuator information, the torque of the second torsion bar, and the rate of change of steering wheel angle are input into the torque calculation model to obtain the desired motor torque.

[0039] The torque calculation model is as follows:

[0040]

[0041] and These are the first and second derivatives of the steering wheel angle, τ. s For the desired motor torque, τ t This represents the torque of the second torsion bar.

[0042] Secondly, this application provides a vehicle lateral control device applied to an electro-hydraulic steering system. The electro-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, 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. The other end of the screw 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] The acquisition module is used to acquire vehicle information and steering wheel angle change rate. The steering wheel angle change rate includes the first and second derivatives of the steering wheel angle. The vehicle information includes basic vehicle body information, longitudinal velocity information, actual position information, and planned position information. The planned position information is the position information that is 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 gravity to the front wheel, distance from the vehicle center of gravity 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 desired front wheel steering angle based on the planned position information, actual position information, vehicle body basic information, and longitudinal speed information;

[0046] The 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 based on the lateral force of the front wheel.

[0047] The second inner layer control module is used to call the inner layer controller to calculate the rotation angle of the second torsion bar based on the reaction torque, and to calculate the desired motor torque based on the rotation angle of the second torsion bar and the steering wheel angle change rate.

[0048] The third inner layer control module is used to call the inner layer controller to calculate the desired front wheel angle by multiplying the desired front wheel angle and the preset wheel transmission ratio. Based on the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, the desired steering wheel angle is calculated. 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.

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

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

[0051] The error change rate module is used to determine the position error and direction error based on the planned position information and the actual position information, and to generate the position error change rate and direction error change rate based on the position error at multiple times and the direction error at multiple times.

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

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

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

[0055] In one possible design, the module for calculating the lateral force of the front wheels also includes: a construction module, an iteration module, and a prediction module;

[0056] The module is used to construct the error vector of the synovial observer, which includes: yaw rate error, front wheel lateral force error, and rear wheel lateral force error;

[0057] The iteration module is used to iteratively train the slid observer based on the error vector to obtain multiple gains of the slid observer.

[0058] The prediction module is used to predict the lateral force of the front wheels using multiple gains from the synovial observer;

[0059] The formula for predicting the lateral force of the front wheel using a synovial membrane observer is as follows:

[0060]

[0061] in, To predict yaw rate, I represents the vehicle's moment of inertia, a is the distance from the vehicle's center of mass to the front wheel, b is the distance from the vehicle's center of mass to the rear wheel, and ρ1 to ρ6 are the six gains of the slicker observer. For the predicted front wheel lateral force, The predicted rate of change of the front wheel lateral force. For the predicted rear wheel lateral force, The predicted rate of change of the rear wheel lateral force. a is the actual yaw rate. y It is the actual lateral acceleration. It predicts lateral acceleration, and sgn is a function that takes the positive or negative sign.

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

[0063] The wheel-axle distance module is used to obtain the wheel-axle distance of the vehicle, which is the distance between the center of the wheel and the center of the axle;

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

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

[0066] The system information acquisition module is used to acquire system information of the electro-hydraulic steering system. This system information includes: the piston side surface area A of the piston. P The radius R of the sector gear sg 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 and lower chambers of the cylinder, and the preset reduction ratio i sg The stiffness K of the second torsion bar t ;

[0067] The second input module is used to input system information and reaction torque into the second torsion bar angle calculation model to obtain the rotation angle of the second torsion bar.

[0068] The calculation model for the second torsion bar angle is as follows:

[0069]

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

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

[0072] The second product module is used to calculate the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar, which is the torque of the second torsion bar.

[0073] The actuator information acquisition module is used to acquire steering actuator information, including 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 ;

[0074] The 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 desired motor torque.

[0075] The torque calculation model is as follows:

[0076]

[0077] and These are the first and second derivatives of the steering wheel angle, τ. s For the desired motor torque, τ t This represents the torque of the second torsion bar.

[0078] Thirdly, this application provides an electronic device, including: a processor, and a memory communicatively connected to the processor;

[0079] The memory stores instructions that the computer executes;

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

[0081] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement a vehicle lateral control method according to the first aspect of the invention.

[0082] Fifthly, this 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 first aspect of the invention.

[0083] This application provides a vehicle lateral control method, device, equipment, medium, and product. The vehicle lateral control method is applied to an electro-hydraulic steering system. The electro-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, a sector gear, a steering drop arm, and a cylinder. The cylinder includes a piston and a cylinder body. The wheel system includes: front wheels and steering tie rods. 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... The reducer has two ends connected to the reducer and one end of the screw, respectively. The other end of the screw is connected to the piston, which is connected to the sector gear. The two ends of the steering arm are connected to the sector gear and one end of the steering tie rod, respectively. The other end of the steering tie rod is connected to the front wheel. The method includes: acquiring vehicle information and the steering wheel angle change rate, the steering wheel angle change rate including the first and second derivatives of the steering wheel angle, and the vehicle information including: basic vehicle body information, longitudinal speed information, actual position information, and planned position information. The planned position information is the closest to the actual position information in the pre-generated planned path. The system retrieves location information and basic vehicle information, including wheel lateral stiffness, distance from the vehicle's center of gravity to the front wheels, distance from the vehicle's center of gravity to the rear wheels, vehicle mass, and vehicle moment of inertia. It then calls the outer controller to calculate the desired front wheel steering angle based on the planned location information, actual location information, basic vehicle information, and longitudinal velocity information. Next, it calls the inner controller to calculate the front wheel lateral force and, based on this force, calculate the reaction torque applied to the sector gear. Finally, it calls the inner controller to calculate the rotation angle of the second torsion bar based on the reaction torque and, based on the rotation angle of the second torsion bar and the steering wheel angle change rate, calculates the desired electric... The system calculates the desired front wheel angle by multiplying the desired front wheel angle by the preset wheel transmission ratio, and then calculates the desired steering wheel angle based on 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, which is the product of the desired sector gear angle and the preset reduction ratio. The system then calls the inner controller to control the motor operation based on the desired motor torque and to control the steering wheel rotation based on the desired steering wheel angle. The following technical effects were achieved: the outer controller calculates the desired front wheel angle of the vehicle based on vehicle information, and the inner controller calculates the desired steering wheel angle and desired motor torque, which are non-linearly related to the desired front wheel angle, based on the desired front wheel angle and vehicle information, thus reducing the error between the desired steering wheel angle and the actual vehicle requirements; by calling the inner controller to control the motor operation based on the desired motor torque, and by calling the inner controller to control the steering wheel rotation based on the desired steering wheel angle, the accuracy of lateral control of heavy vehicles was improved. Attached Figure Description

[0084] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

[0086] Figure 1 This is a schematic diagram of the structure of the electro-hydraulic steering system provided in the embodiments of this application;

[0087] Figure 2 A flowchart illustrating a vehicle lateral control method provided in this application embodiment. Figure 1 ;

[0088] Figure 3 A flowchart illustrating a vehicle lateral control method provided in this application embodiment. Figure 2 ;

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

[0090] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0091] Figure label:

[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; 123-Sector gear; 124-Steering drop arm; 125-Cylinder; 126-Piston; 127-Cylinder block; 128-Servo valve; 129-Electric pump; 131-Front wheel; 132-Steering tie rod;

[0093] 410 - Acquisition module; 420 - Outer control module; 430 - First inner control module; 440 - Second inner control module; 450 - Third inner control module; 460 - Fourth inner control module;

[0094] 510 - Processor; 520 - Memory; 530 - Communication components; 540 - Bus. Detailed Implementation

[0095] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0096] In the embodiments of this application, the terms "first" and "second" are used to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that "first" and "second" do not necessarily imply difference. It should be noted that in the embodiments of this application, the words "exemplary" or "for example" are used to indicate that something is being used as an example, illustration, or description. Any embodiment or design scheme described as "exemplary" or "for example" in this application should not be construed as being better or more advantageous than other embodiments or design schemes. Specifically, the use of "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner. In the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more.

[0097] It should be noted that the phrase "at...time" in the embodiments of this application can refer to the instant at which a certain situation occurs, or to a period of time after the occurrence of a certain situation; the embodiments of this application do not specifically limit this. Furthermore, the vehicle lateral control method provided in the embodiments of this application is merely an example; a vehicle lateral control method may include more or fewer elements.

[0098] To facilitate a clear description of the technical solutions in the embodiments of this application, some terms and technologies involved in the embodiments of this application will be briefly introduced below:

[0099] Linear Quadratic Regulator (LQR): An optimization control method applicable to linear systems, aiming to minimize a quadratic cost function. The controller is designed by minimizing a quadratic performance index, achieving an optimal balance between the system state and control input.

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

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

[0102] The sign function, usually denoted as sgn, is 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; and when x < 0, sgn(x) = -1.

[0103] Front wheel lateral force: This refers to the force perpendicular to the direction of travel that acts on the front tires of a heavy vehicle during operation. This force can be caused by factors such as wind force and road surface inclination, resulting in the wheel deflecting to the side.

[0104] In the intelligent driving process of heavy-duty vehicles, lateral control ensures that the vehicle maintains a proper lateral position during operation. Due to their length and weight, heavy-duty vehicles are more susceptible to factors such as wind resistance and uneven road surfaces, thus requiring lateral control to maintain stability. Furthermore, lateral control effectively prevents traffic accidents caused by directional deviations or loss of control, ensuring driving safety.

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

[0106] However, while this method achieves some control over heavy vehicles, it still has some shortcomings, especially in terms of the precision of lateral control. Specifically, due to the long body and heavy load of heavy vehicles, they typically employ electro-hydraulic power steering systems, making it impossible to simply express the relationship between the steering wheel angle and the front wheel angle using a linear method. Therefore, the simple proportional conversion in existing technologies cannot accurately reflect the actual lateral movement requirements of the vehicle, leading to significant deviations when performing operations such as lane keeping and lane changing, thus affecting driving safety and comfort.

[0107] Based on this, embodiments of this application propose a vehicle lateral control method, device, equipment, medium, and product, which can be used in the field of intelligent driving technology and aims to solve the above-mentioned technical problems of the prior art. By fully considering the nonlinear relationship between the vehicle's steering wheel angle and front wheel angle, rather than directly converting the desired front wheel angle into the desired steering wheel angle and desired motor torque through a linear proportional relationship, and by leveraging the cascaded outer and inner controllers in synergy, lateral control of heavy vehicles is achieved, thereby improving the accuracy of lateral control of heavy vehicles. Specifically, the outer controller calculates the desired front wheel angle based on vehicle information, and the inner controller calculates the desired steering wheel angle and desired motor torque, which have a nonlinear relationship with the desired front wheel angle, based on the desired front wheel angle and vehicle information, thereby reducing the error between the desired steering wheel angle and the actual vehicle requirements.

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

[0109] First, the hardware system applicable to a vehicle lateral control method in one embodiment of this application will be described in detail.

[0110] One vehicle lateral control method in this application embodiment can be applied to an electro-hydraulic steering system. Figure 1 This is a schematic diagram of the electro-hydraulic steering system provided in an embodiment of this application. Figure 1 As shown, the electro-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 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 both 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 122. The other end of the screw 122 is connected to the piston 126. The piston 126 is connected to the sector gear 123. The two ends of the steering drop arm 124 are respectively connected to the sector gear 123 and one end of the steering tie rod 132. The other end of the steering tie rod 132 is connected to the front wheel 131.

[0111] Specifically, this application embodiment achieves lateral control of a heavy vehicle through the combined action of a cascaded outer controller and an inner controller. The outer controller calculates the desired front wheel steering angle of the heavy vehicle based on its dynamic model. The inner controller constructs a simplified physical model of the heavy vehicle's electro-hydraulic steering system based on the structure and operating principle of the electro-hydraulic power steering mechanism.

[0112] The working process of the electro-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 this rotation to the second torsion bar 121.

[0113] In the intelligent driving mode of heavy-duty 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 command from the inner controller, it will rotate and generate corresponding torque. This torque is amplified by the reducer 114 and can be used to push 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. The screw 122 is connected to the piston 126, thereby converting the rotational motion of the second torsion bar 121 into the translational motion of the piston 126 in the cylinder 125. That is, the piston 126 moves up and down in response to the torsion of the second torsion bar 121. Furthermore, the hydraulic power module 120 also includes an electro-hydraulic circuit consisting of a symmetrical Wheatstone bridge powered by a fixed displacement pump (electric pump 129). Figure 1 In the electro-hydraulic circuit on the right side of cylinder 125, there is also an electric pump 129 and multiple symmetrical servo valves 128. By controlling the electric pump 129 and multiple servo valves 128 in the electro-hydraulic circuit, the flow rate of gas in the hydraulic circuit can be controlled, thereby creating a pressure difference between the upper and lower sides of piston 126, which in turn pushes piston 126 to perform vertical translational movement.

[0115] like Figure 1 As shown, the piston 126 has teeth on its left side, which 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] As can be seen from the above-described electro-hydraulic steering system, 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 electro-hydraulic circuit through the pressure difference generated on both sides of the piston 126, which causes the piston 126 to move up and down to drive the sector gear 123 to rotate.

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

[0118] Next, a vehicle lateral control method provided in the embodiments of this application will be described in detail.

[0119] Figure 2 A flowchart illustrating a vehicle lateral control method provided in this application embodiment. Figure 1 .

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

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

[0122] In this embodiment, the executing entity of a vehicle lateral control method can be an Electronic Control Unit (ECU) in the vehicle. This ECU can be a controller specifically designed for vehicle lateral control, or it can be an existing Steering Control Unit (SCU) in the vehicle; no specific limitation is made here. The ECU can achieve lateral control of heavy vehicles by further controlling cascaded outer and inner controllers.

[0123] The rate of change of steering wheel angle includes the first and second derivatives of the steering wheel angle. Vehicle information includes basic vehicle body information, longitudinal velocity 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 the vehicle center of gravity to the front wheel, distance from the vehicle center of gravity to the rear wheel, vehicle mass, and vehicle moment of inertia.

[0124] Specifically, the steering wheel angle can be acquired through sensors in heavy-duty vehicles. This means that the first and second derivatives of the steering wheel angle can be calculated in real time based on multiple historically acquired steering wheel angles. Basic vehicle body information can be pre-stored in the vehicle's ECU, while longitudinal speed and actual position information can be acquired through sensors in heavy-duty vehicles.

[0125] S202, The outer controller is invoked to calculate the desired front wheel steering angle based on the planned position information, actual position information, vehicle body basic information, and longitudinal speed information.

[0126] Specifically, the ECU can call the outer controller to calculate the desired front wheel steering angle based on the acquired planned position information, actual position information, vehicle body basic information, and longitudinal speed information, using existing technologies such as chassis dynamics models.

[0127] S203. Call the inner layer controller to calculate the lateral force of the front wheel, and calculate the reaction torque applied to the sector gear based on the lateral force of the front wheel.

[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, based on the front wheel lateral force, calculate the reaction torque applied to the sector gear through a monorail vehicle dynamics model or a synovial observer.

[0129] S204. Call the inner layer controller to calculate the rotation angle of the second torsion bar based on the reaction torque, and calculate the desired motor torque based on 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 based on the reaction torque applied to the sector gear, and then calculate the desired motor torque based on the rotation angle of the second torsion bar and the rate of change of the steering wheel angle.

[0131] S205. The inner layer 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. Based on the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, the desired steering wheel angle is calculated.

[0132] In this embodiment, 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. The screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio.

[0133] Specifically, the ECU can calculate the product of the desired front wheel steering angle and the preset wheel gear ratio by calling the inner controller to obtain the desired sector gear angle. Then, based on the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, it can calculate the desired steering wheel angle. The formula for calculating 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] Where, θ s For the desired steering wheel angle, a t Let i be the rotation angle of the second torsion bar. sg θ is the preset reduction ratio between the screw and the sector gear. g For the desired sector gear angle, i gs δ is the preset wheel transmission ratio. f The desired front wheel steering angle.

[0136] S206. Call the inner layer controller to control the motor operation according to the desired motor torque, and call the inner layer controller to control the steering wheel rotation according to the desired steering wheel angle.

[0137] Specifically, after the ECU calculates the desired steering wheel angle and desired motor torque, which are non-linearly related to the desired front wheel angle of the vehicle, it can call the inner controller to control the motor operation according to the desired motor torque. At the same time, it can call the inner controller to control the steering wheel rotation according to the desired steering wheel angle to improve the accuracy of lateral control of heavy vehicles.

[0138] This embodiment provides a vehicle lateral control method, which includes: acquiring vehicle information and steering wheel angle change rate, wherein the steering wheel angle change rate includes the first and second derivatives of the steering wheel angle; the vehicle information includes: basic vehicle body information, longitudinal velocity 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's center of gravity to the front wheel, distance from the vehicle's center of gravity to the rear wheel, vehicle mass, and vehicle moment of inertia; calling an outer controller to calculate the desired front wheel steering angle based on the planned position information, actual position information, basic vehicle body information, and longitudinal velocity information; and calling an inner controller to calculate the front wheel lateral force and calculate the force applied to the fan-shaped... The reaction torque on the gear; the inner controller is invoked to calculate the rotation angle of the second torsion bar based on the reaction torque, and the desired motor torque is calculated based on the rotation angle of the second torsion bar and the steering wheel angle change rate; the inner controller is invoked to calculate the desired sector gear angle by multiplying the desired front wheel angle and the preset wheel transmission ratio, and the desired steering wheel angle is calculated based on 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, and the screw rotation angle is the product of the desired sector gear angle and the preset reduction ratio; the inner controller is invoked to control the motor operation based on the desired motor torque, and the inner controller is invoked to control the steering wheel rotation based on the desired steering wheel angle.

[0139] The following technical effects were achieved: the outer controller calculates the desired front wheel angle of the vehicle based on vehicle information, and the inner controller calculates the desired steering wheel angle and desired motor torque, which are non-linearly related to the desired front wheel angle, based on the desired front wheel angle and vehicle information, thus reducing the error between the desired steering wheel angle and the actual vehicle requirements; by calling the inner controller to control the motor operation based on the desired motor torque, and by calling the inner controller to control the steering wheel rotation based on the desired steering wheel angle, the accuracy of lateral control of heavy vehicles was improved.

[0140] Figure 3 A flowchart illustrating a vehicle lateral control method provided in this application embodiment. Figure 2 In one possible example, such as Figure 3 As shown, in this embodiment... Figure 2 Based on the examples, a detailed explanation is provided on how to calculate the desired front wheel steering angle and the desired motor torque. For example... 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 again in this embodiment.

[0143] S302. Determine the position error and direction error based on the planned position information and the actual position information, and generate the position error change rate and direction error change rate based on the position error at multiple times and the direction error at multiple times.

[0144] Specifically, the outer controller can achieve trajectory tracking and lateral control of heavy vehicles based on error tracking. Specifically, calling the outer controller to calculate the desired front wheel steering angle based on the chassis dynamics model includes: first, determining the position error and direction error based on the planned position information and the actual position information; the specific calculation formula is as follows:

[0145]

[0146]

[0147] Among them, e y θ represents the positional error between the actual and planned positions of the heavy vehicle. The planned position refers to the position on the pre-generated planned path that is closest to the actual position of the heavy vehicle. dmin To determine the orientation of the planned location, x is the horizontal coordinate of the actual position of the heavy vehicle, and y is the vertical coordinate of the actual position of the heavy vehicle. dmin Let y be the x-coordinate of the planned location. dmin The vertical coordinate of the planned location, k represents the directional error between the actual and planned positions of the heavy vehicle. r Let be the curvature of the planned path at the planned location.

[0148] Then, based on the position error e at multiple times y and direction error at multiple times Generate position error change rate and the rate of change of direction error

[0149] S303. Input the vehicle's basic information, longitudinal velocity information, position error, direction error, rate of change of position error, and rate of change of direction error into the vehicle's state-space equations to calculate the desired front wheel steering angle δ. f .

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

[0151]

[0152] Among them, C af For the front wheel lateral stiffness, C arLet V be the rear wheel lateral stiffness, m be the vehicle mass (i.e., the total mass of a heavy vehicle), a be the distance from the vehicle's center of gravity to the front wheel, b be the distance from the vehicle's center of gravity to the rear wheel, and V be the lateral stiffness. x Let I be the longitudinal velocity of the heavy vehicle, and let I be the vehicle's moment of inertia. This refers to the yaw angle of the heavy vehicle's actual position. This represents the actual yaw rate. Based on the vehicle's state-space equations, the desired front wheel steering angle δ can be calculated using either the LQR or MPC algorithm. f .

[0153] S304. Construct the error vector of the sliding membrane observer.

[0154] Specifically, the ECU can predict the front wheel lateral force F based on the basic principles of the synovial observation system. yf First, the inner controller is invoked to construct the error vector of the sliding membrane observer. Error vector This includes: yaw rate error Front wheel lateral force error and rear wheel lateral force error Error vector As shown in the following formula:

[0155]

[0156] in, This is the actual yaw rate. To predict the yaw rate, F yf The lateral force is from the front wheel. For the predicted front wheel lateral force, F yr The lateral force is from the rear wheel. This represents the predicted lateral force on the rear wheel.

[0157] S305. Iteratively train the slug observer based on the error vector to obtain multiple gains of the slug observer.

[0158] In this embodiment of the application, in order to construct the synovial membrane observer, the lateral force F of the front wheel is... yf The rate of change, and the lateral force F of the rear wheel yr The rate of change is considered to be 0, that is in, The lateral force F of the front wheel yf rate of change, The lateral force F of the rear wheel yr Rate of change. This can be used... R 3 This indicates the predicted state, due to the yaw rate. and lateral acceleration a y This can be detected by sensors, allowing the measurement output of the synovial membrane observer to be...

[0159] The formula for predicting the lateral force of the front wheel using a synovial membrane observer is as follows:

[0160]

[0161] in, To predict yaw rate, I represents the vehicle's moment of inertia, a is the distance from the vehicle's center of mass to the front wheel, b is the distance from the vehicle's center of mass to the rear wheel, and ρ1 to ρ6 are the six gains of the slicker observer. For the predicted front wheel lateral force, The predicted rate of change of the front wheel lateral force. For the predicted rear wheel lateral force, The predicted rate of change of the rear wheel lateral force. a is the actual yaw rate. y It is the actual lateral acceleration. It predicts lateral acceleration, and sgn is a function that takes the positive or negative sign.

[0162] According to the error vector Iteratively train the synovial observer to make the error vector The convergence to 0 yields the six gains ρ1 to ρ6 of the synovial observer.

[0163] The constraints for the six gains ρ1 to ρ6 in this embodiment are shown in the following equations:

[0164]

[0165] ρ3=-ρ5>0

[0166]

[0167] By continuously adjusting the six gains ρ1 to ρ6 of the sliding diaphragm observer, the error vector of the sliding diaphragm observer is made... The predicted state tends to zero. This means that through multiple iterations and adjustments, the predicted state quickly converges to the true state, even if the predicted yaw rate in the predicted state... Compared with the actual yaw rate Consistent with the predicted front wheel lateral force Compared to the actual front wheel lateral force F yf Consistent with the predicted rear wheel lateral force Compared to the actual rear wheel lateral force F yr Consistent.

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

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

[0170]

[0171]

[0172]

[0173] in, This is the lateral acceleration error. It is achieved by adjusting the yaw rate error. Front wheel lateral force error and rear wheel lateral force error The rate of change of all values ​​is 0, so the synovial observer is iteratively trained to obtain the six gains ρ1 to ρ6 of the synovial observer.

[0174] S306. Predict the lateral force of the front wheel using multiple gains from the synovial observer.

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

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

[0177] Specifically, in the dynamic model of a monorail vehicle, 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 It is lateral acceleration. Let be the vehicle's moment of inertia, a be the distance from the vehicle's center of mass to the front wheel, and b be the distance from the vehicle's center of mass to the rear wheel.

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

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

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

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

[0185] τ p =F yf ×d×c

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

[0187] S309. Obtain system information for the electro-hydraulic steering system.

[0188] In this embodiment of the application, the system information includes: the piston side surface area A of the piston. P The radius R of the sector gear sg 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 and lower chambers of the cylinder, and the preset reduction ratio i sg The stiffness K of the second torsion bar t .

[0189] After calculating the reaction torque of the lateral force applied to the sector gear by the front wheels, the ECU can calculate the rotation angle of the second torsion bar based on the reaction torque. First, it further obtains the system information of the electro-hydraulic steering system to calculate the rotation angle of the second torsion bar based on the system information and the reaction torque.

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

[0191] In this embodiment, the formula for calculating the second torsion bar angle is as follows:

[0192]

[0193] sgn(ΔP) is the sign of ΔP, τ P For the reaction torque, A PR is the piston side surface area of ​​the piston. sg For the radius of the sector gear, C n For the internal structural parameters of the steering actuator, K le 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, and i sg For the preset reduction ratio, K t For the stiffness of the second torsion bar, a t Let be the rotation angle of the second torsion bar. The rotation angle 'a' of the second torsion bar can be obtained by solving the formula of the second torsion bar angle calculation model. t .

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

[0195]

[0196] Among them, J r Let θ be the equivalent inertia between the screw and the sector gear, and let θ be a preset value. g For the desired sector gear angle, f vr f is the equivalent damping coefficient between the screw and the sector gear. fr τ is the nonlinear friction coefficient during vehicle steering. t F is the torque of the second torsion bar. hps F is the thrust generated on the piston by the pressure difference of the gas 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 P is the gas pressure in the upper chamber located above the piston. D The gas pressure in the lower chamber located 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 all of them, and put F hps Substituting the calculation formula into the calculation formula of the motion model of the hydraulic power module, we can obtain:

[0199] i sg K t a t +A P Rsg ΔP=τ P ;

[0200] Then rotate the second torsion bar by an angle α. t Substituting the relationship with the pressure difference ΔP into the above formula, we can obtain the formula for calculating the angle of the second torsion bar. Wherein, the rotation angle α of the second torsion bar... t The relationship between the pressure difference ΔP and the pressure difference is as follows:

[0201]

[0202] Among them, C n These are the internal structural parameters of the steering actuator, which can be preset values.

[0203] S311. Calculate the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar, which is 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] Where, τ t K represents the torque of the second torsion bar. t For the stiffness of the second torsion bar, a t Let be 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 The damping coefficient f of the steering actuator vs The friction coefficient f of the steering actuator sf To calculate the desired motor torque, further information about the steering actuator can be obtained.

[0209] S313. 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 desired motor torque.

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

[0211]

[0212] and These are the first and second derivatives of the steering wheel angle, τ. s For the desired motor torque, τ tThis represents the torque of the second torsion bar.

[0213] S314. The inner layer 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. Based on the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, the desired steering wheel angle is calculated.

[0214] S315, Call the inner layer controller to control the motor operation according to the desired motor torque, and call the inner layer controller to control the steering wheel rotation according to the desired steering wheel angle.

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

[0216] This application provides a vehicle lateral control method that constructs an error vector for a slicker observer, iteratively trains the slicker observer based on the error vector, and obtains the front wheel lateral force of a heavy vehicle when the error vector converges to 0. This improves the accuracy of the calculated front wheel lateral force, thereby improving the accuracy of the desired motor torque and desired steering wheel angle calculated based on the front wheel lateral force, and ultimately improving the accuracy of the lateral control of the heavy vehicle. Furthermore, by establishing a second torsion bar angle calculation model that includes the pressure difference between the upper and lower chambers of the cylinder, the nonlinear relationship between the electro-hydraulic circuit and the rotation angle of the second torsion bar is fully considered when calculating the rotation angle of the second torsion bar, improving the calculation accuracy of the second torsion bar rotation angle, and thus improving the accuracy of the desired motor torque and desired steering wheel angle calculated based on the rotation angle of the second torsion bar. Finally, by inputting lateral acceleration, the distance from the vehicle's center of gravity to the front wheel, the distance from the vehicle's center of gravity to the rear wheel, the vehicle's mass, and the vehicle's moment of inertia into a monorail vehicle dynamic model, the front wheel lateral force is calculated, providing another method for calculating the front wheel lateral force.

[0217] In this embodiment of the invention, electronic devices or main control devices can be divided into functional modules according to the above method examples. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing unit. The integrated unit can be implemented in hardware or as a software functional module. It should be noted that the module division in this embodiment of the invention is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0218] Figure 4This is a schematic diagram of a vehicle lateral control device provided in an embodiment of this application. The vehicle lateral control device is applied to an electro-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, a sector gear, a steering drop arm, and a cylinder. The cylinder includes a piston and a cylinder body. The wheel system includes front wheels and steering tie rods. 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. The other end of the screw 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 wheels.

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

[0220] The acquisition module 410 is used to acquire vehicle information and steering wheel angle change rate. The steering wheel angle change rate includes the first and second derivatives of the steering wheel angle. The vehicle information includes basic vehicle body information, longitudinal velocity 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 gravity to the front wheel, distance from the vehicle center of gravity 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 desired front wheel steering angle based on the planned position information, actual position information, vehicle body basic information, and longitudinal speed information;

[0222] The first inner layer control module 430 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 based on the lateral force of the front wheel.

[0223] The second inner layer control module 440 is used to call the inner layer controller to calculate the rotation angle of the second torsion bar based on the reaction torque, and to calculate the desired motor torque based on 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 desired front wheel angle by multiplying the desired front wheel angle and the preset wheel transmission ratio to obtain the desired sector gear angle. Based on the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, the desired steering wheel angle is calculated. 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 layer control module 460 is used to call the inner layer controller to control the motor operation according to the desired motor torque, and to call the inner layer controller to control the steering wheel rotation according to the desired 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] The error change rate module is used to determine the position error and direction error based on the planned position information and the actual position information, and to generate the position error change rate and direction error change rate based on the position error at multiple times and the direction error at multiple times.

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

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

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

[0231] In one possible design, the module for calculating the lateral force of the front wheels also includes: a construction module, an iteration module, and a prediction module;

[0232] The module is used to construct the error vector of the synovial observer, which includes: yaw rate error, front wheel lateral force error, and rear wheel lateral force error;

[0233] The iteration module is used to iteratively train the slid observer based on the error vector to obtain multiple gains of the slid observer.

[0234] The prediction module is used to predict the lateral force of the front wheels using multiple gains from the synovial observer;

[0235] The formula for predicting the lateral force of the front wheel using a synovial membrane observer is as follows:

[0236]

[0237] in, To predict yaw rate, I represents the vehicle's moment of inertia, a is the distance from the vehicle's center of mass to the front wheel, b is the distance from the vehicle's center of mass to the rear wheel, and ρ1 to ρ6 are the six gains of the slicker observer. For the predicted front wheel lateral force, The predicted rate of change of the front wheel lateral force. For the predicted rear wheel lateral force, The predicted rate of change of the rear wheel lateral force. a is the actual yaw rate. y It is the actual lateral acceleration. It predicts lateral acceleration, and sgn is a function that takes the positive or negative sign.

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

[0239] The wheel-axle distance module is used to obtain the wheel-axle distance of the vehicle, which is the distance between the center of the wheel and the center of the axle;

[0240] The first product module is used to calculate the product of the front wheel lateral force, wheel-axle distance, and a preset proportional coefficient to obtain the 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 system information of the electro-hydraulic steering system. This system information includes: the piston side surface area A of the piston. P The radius R of the sector gear sg 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 and lower chambers of the cylinder, and the preset reduction ratio i sg The stiffness K of the second torsion bar t ;

[0243] The second input module is used to input system information and reaction torque into the second torsion bar angle calculation model to obtain the rotation angle of the second torsion bar.

[0244] The calculation model for the second torsion bar angle is as follows:

[0245]

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

[0247] In one 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] The second product module is used to calculate the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar, which is the torque of the second torsion bar.

[0249] The actuator information acquisition module is used to acquire steering actuator information, including 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 ;

[0250] The 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 desired motor torque.

[0251] The torque calculation model is as follows:

[0252]

[0253] and These are the first and second derivatives of the steering wheel angle, τ. s For the desired motor torque, τ t This represents the torque of the second torsion bar.

[0254] The vehicle lateral control device provided in this embodiment can execute a vehicle lateral control method of the above embodiment. Its implementation principle and technical effect are similar, and will not be described again here.

[0255] In a specific implementation of the aforementioned vehicle lateral control device, each module can be implemented as a processor. The processor can execute computer execution instructions stored in the memory, thereby enabling the processor to execute 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 this 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, memory 520, and communication component 530 are connected via a bus 540.

[0257] In the specific implementation process, at least one processor 510 executes computer execution instructions stored in memory 520, causing at least one processor 510 to execute a vehicle lateral control method as executed on the electronic device side as described above.

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

[0259] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

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

[0261] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0262] The above description of the functions implemented by electronic devices and main control devices has introduced the solutions provided by the embodiments of the present invention. It is understood that, in order to implement the above functions, the electronic device or main control device includes hardware structures and / or software modules corresponding to the execution of each function. By combining the units and algorithm steps of the various examples described in the embodiments of the present invention, the embodiments of the present invention can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by 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 beyond the scope of the technical solutions of the embodiments of the present invention.

[0263] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the vehicle lateral control method described above.

[0264] The aforementioned 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 storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0265] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from 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 reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in an electronic device or a host device.

[0266] This application also provides a computer program product, which includes a computer program stored in a readable storage medium. At least one processor of an electronic device can read the computer program from the readable storage medium, and the at least one processor executes the computer program to cause the electronic device to perform the solution provided in any of the above embodiments.

[0267] Those skilled in the art will appreciate that all or part of the steps in the above-described method embodiments can be implemented using hardware associated with program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[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 scope of protection of the present application is obviously not limited to these specific embodiments. 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, ordinary technicians in this field 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 solution 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, This invention relates to an electro-hydraulic steering system, comprising: 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, a sector gear, a steering 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. The other end of the screw is connected to the piston, and the piston is connected to the sector gear. The two ends of the steering 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. The method includes: The system acquires vehicle information and steering wheel angle change rate, wherein the steering wheel angle change rate includes the first and second derivatives of the steering wheel angle; the vehicle information includes basic vehicle body information, longitudinal velocity 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; and the basic vehicle body information includes wheel lateral stiffness, distance from the vehicle center of gravity to the front wheel, distance from the vehicle center of gravity to the rear wheel, vehicle mass, and vehicle moment of inertia. The outer controller is invoked to calculate the desired front wheel steering angle based on the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information; The inner layer controller is invoked to calculate the lateral force of the front wheels, and the reaction torque applied to the sector gear is calculated based on the lateral force of the front wheels. The inner layer controller is invoked to calculate the rotation angle of the second torsion bar based on the reaction torque, and the desired motor torque is calculated based on the rotation angle of the second torsion bar and the steering wheel angle change rate. The inner layer controller calculates the desired front wheel angle by multiplying the desired front wheel angle by the preset wheel transmission ratio. Then, based on the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, the desired steering wheel angle is calculated. 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. The inner controller is invoked to control the operation of the motor according to the desired motor torque, and the inner controller is invoked 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 step of calculating the desired front wheel steering angle based on the planned location information, the actual location information, the vehicle body basic information, and the longitudinal speed information includes: The position error and direction error are determined based on the planned position information and the actual position information, and the position error change rate and direction error change rate are generated based on the position error at multiple times and the direction error at multiple times. The vehicle's basic information, longitudinal speed information, position error, direction error, rate of change of position error, and rate of change of direction error are input into the vehicle's state-space equation to calculate the desired front wheel steering 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's center of gravity to the front wheel, the distance from the vehicle's center of gravity to the rear wheel, the vehicle's mass, and the vehicle's moment of inertia are input into the monorail vehicle dynamic model to obtain the lateral force of the front wheel.

4. The method according to claim 1, characterized in that, The calculation of the front wheel lateral force includes: Construct the error vector of the synovial observer, which includes: yaw rate error, front wheel lateral force error, and rear wheel lateral force error; The synovial observer is iteratively trained based on the error vector to obtain multiple gains of the synovial observer. The lateral force of the front wheel is predicted using multiple gains of the synovial observer; The formula used by the synovial observer to predict the lateral force of the front wheel is as follows: Among them, the To predict yaw rate, I represents the vehicle's moment of inertia, a represents the distance from the vehicle's center of mass to the front wheel, b represents the distance from the vehicle's center of mass to the rear wheel, and ρ1 to ρ6 represent the six gains of the slicker observer. For the predicted front wheel lateral force, the The predicted rate of change of the front wheel lateral force, the To predict the lateral force of the rear wheel, the The predicted rate of change of the rear wheel lateral force, the The actual yaw rate, a y It is the actual lateral acceleration, the stated It predicts lateral acceleration, where sgn is a function that takes the sign of its component.

5. The method according to any one of claims 1 to 4, characterized in that, The calculation of the reaction torque applied to the sector gear based on the lateral force of the front wheel includes: Obtain the axle distance of the vehicle, where the axle distance is the distance between the center of the wheel and the center of the axle; 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 calculation of the rotation angle of the second torsion bar based on the reaction torque includes: Obtain system information of the electro-hydraulic steering system, the system information including: the piston side surface 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 and lower chambers of the cylinder, and the preset reduction ratio i sg The stiffness K of the second torsion bar t ; The system information and the reaction torque are input into the second torsion bar angle calculation model to obtain the rotation angle of the second torsion bar; The calculation model for the second torsion bar angle is as follows: The sgn(ΔP) is the sign of ΔP, and the τ P For the reaction torque, the a t The rotation angle of the second torsion bar.

7. The method according to claim 6, characterized in that, The step of calculating the desired motor torque based on the rotation angle of the second torsion bar and the rate of change of the steering wheel angle includes: Calculate the product of the stiffness of the second torsion bar and the rotation angle of the second torsion bar, and use it as the torque of the second torsion bar; Obtain steering actuator information, the steering actuator information including 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 ; The steering actuator information, the torque of the second torsion bar, and the steering wheel angle change rate are input into the torque calculation model to obtain the desired motor torque. The torque calculation model is as follows: The and stated These are the first and second derivatives of the steering wheel angle, respectively, and τ s For the desired motor torque, the τ t This represents the torque of the second torsion bar.

8. A vehicle lateral control device, characterized in that, This invention relates to an electro-hydraulic steering system, comprising: 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, a sector gear, a steering 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. The other end of the screw is connected to the piston, and the piston is connected to the sector gear. The two ends of the steering 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. The device comprises: The acquisition module is used to acquire vehicle information and steering wheel angle change rate. The steering wheel angle change rate includes the first and second derivatives of the steering wheel angle. The vehicle information includes basic vehicle body information, longitudinal velocity 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 gravity to the front wheel, distance from the vehicle center of gravity to the rear wheel, vehicle mass, and vehicle moment of inertia. The outer control module is used to call the outer controller to calculate the desired front wheel steering angle based on the planned position information, the actual position information, the vehicle body basic information, and the longitudinal speed information; The 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 based on the lateral force of the front wheel. The second inner layer control module is used to call the inner layer controller to calculate the rotation angle of the second torsion bar based on the reaction torque, and to calculate the desired motor torque based on the rotation angle of the second torsion bar and the steering wheel angle change rate. The third inner layer control module is used to call the inner layer controller to calculate the desired sector gear angle by multiplying the desired front wheel angle and the preset wheel transmission ratio. Based on the rotation angle of the second torsion bar, the desired sector gear angle, and the preset reduction ratio, the desired steering wheel angle is calculated. 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. The fourth inner layer control module is used to call the inner layer controller to control the motor to run according to the desired motor torque, and to call the inner layer controller to control the steering wheel to rotate according to the desired 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-executed instructions; The processor executes computer execution instructions stored in the memory to implement the vehicle lateral control method as described in 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, which, when executed by a processor, are used to implement the vehicle lateral control method as described in 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 the processor, it implements the vehicle lateral control method as described in any one of claims 1 to 7.

Images