Lane change path keeping method, device, equipment and storage medium

Abstract

This application relates to the field of vehicle control technology and discloses a lane change path maintenance method, apparatus, device, and storage medium. The method comprises: constructing a vehicle dynamics model when a vehicle experiences a steering failure; determining a desired yaw moment for the vehicle based on the vehicle dynamics model; and distributing the desired yaw moment to each wheel of the vehicle to maintain the lane change path. This application enables the vehicle to maintain lane change functionality when the steering system fails during a lane change, thereby improving the safety of the vehicle lane change process.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a lane change path keeping method, device, equipment and storage medium. Background Art

[0002] Currently, hardware such as the solenoid valve in the steering system is used to address the problem of partial steering failure. However, the capabilities of the chassis system are not fully utilized, especially the effect of the four wheel hub motors of four-wheel independent drive electric vehicles on tire force. Furthermore, the path keeping capability is not considered. As a result, when the steering system fails during the lane change process, the vehicle cannot maintain the lane changing function, resulting in poor lane changing safety.

[0003] Therefore, how to maintain the vehicle's lane-changing function when the vehicle's steering system fails during the lane-changing process and improve the safety of the vehicle's lane-changing process is a problem that urgently needs to be solved.

[0004] The above content is only used to assist in understanding the technical solution of this application and does not constitute an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of this application is to provide a lane change path maintenance method, device, equipment and storage medium, aiming to solve the technical problem of how to maintain the vehicle's lane changing function when the vehicle's steering system fails during the lane change process and improve the safety of the vehicle's lane changing process.

[0006] To achieve the above objectives, the present application proposes a lane change path keeping method, the method comprising:

[0007] Construct a vehicle dynamics model when a vehicle has a steering failure;

[0008] determining a desired yaw moment of the vehicle based on the vehicle dynamics model;

[0009] The desired yaw moment is distributed to each wheel of the vehicle to maintain the lane change path.

[0010] In one embodiment, determining the desired yaw moment of the vehicle based on the vehicle dynamics model includes:

[0011] controlling the vehicle dynamics model to perform yaw motion to obtain a vehicle dynamics relationship;

[0012] Acquiring vehicle driving parameters, and determining a yaw rate difference and a trajectory lateral deviation based on the vehicle driving parameters;

[0013] determining a sliding mode surface based on the yaw rate difference and the trajectory lateral deviation;

[0014] A desired yaw moment of the vehicle is determined based on the sliding surface and the vehicle dynamics relationship.

[0015] In one embodiment, the vehicle driving parameters include the tire cornering stiffness of the front wheels, the tire cornering stiffness of the rear wheels, the front wheel steering angle, and the actual yaw rate of the vehicle;

[0016] The determining the yaw rate difference according to the vehicle driving parameters includes:

[0017] Calculating according to the tire cornering stiffness of the front wheels of the vehicle, the tire cornering stiffness of the rear wheels, and the front wheel steering angle to obtain a reference yaw rate of the vehicle;

[0018] A yaw rate difference is determined based on the actual yaw rate and the reference yaw rate.

[0019] In one embodiment, the vehicle driving parameter further includes the longitudinal speed of the vehicle;

[0020] Determining the trajectory lateral deviation according to the vehicle driving parameters includes:

[0021] determining an actual driving path of the vehicle according to the longitudinal velocity of the vehicle and the actual yaw rate;

[0022] The lateral deviation of the trajectory is determined based on the actual driving path of the vehicle and the preset planned driving path.

[0023] In one embodiment, determining the desired yaw moment of the vehicle based on the sliding surface and the vehicle dynamics relationship includes:

[0024] Calculating according to the sliding surface to obtain a reaching law;

[0025] A desired yaw moment of the vehicle is determined based on the reaching law and the vehicle dynamics relationship.

[0026] In one embodiment, distributing the desired yaw moment to each wheel of the vehicle comprises:

[0027] Obtain the objective function and constraints of tire force distribution;

[0028] determining a desired longitudinal tire force for each wheel based on the objective function and the constraints;

[0029] The desired yaw moment is distributed to each wheel of the vehicle according to the desired longitudinal tire force of each wheel.

[0030] In one embodiment, obtaining the objective function and constraints of tire force distribution includes:

[0031] Acquiring an axle load transfer condition during vehicle travel, and determining an objective function for tire force distribution based on the axle load transfer condition during vehicle travel;

[0032] Obtain the vehicle's vertical load and tire-road friction coefficient;

[0033] The constraint conditions of tire force distribution are determined based on the obtained vertical load of the vehicle and the tire-road friction coefficient.

[0034] In addition, to achieve the above-mentioned purpose, the present application also proposes a lane-changing path maintaining device, the lane-changing path maintaining device comprising:

[0035] A building module for building a vehicle dynamics model when a steering failure occurs in the vehicle;

[0036] a determination module, configured to determine a desired yaw moment of the vehicle based on the vehicle dynamics model;

[0037] A distribution module is configured to distribute the desired yaw moment to each wheel of the vehicle to maintain a lane change path.

[0038] In addition, to achieve the above-mentioned purpose, the present application also proposes a lane change path keeping device, which includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the computer program is configured to implement the steps of the lane change path keeping method as described above.

[0039] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and stores a computer program on the storage medium. When the computer program is executed by the processor, the steps of the lane change path keeping method described above are implemented.

[0040] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the steps of the lane change path keeping method as described above.

[0041] The present application provides a lane change path maintenance method. The present application first constructs a vehicle dynamics model when a steering failure occurs in the vehicle to facilitate improving computational efficiency; determines a desired yaw moment of the vehicle based on the vehicle dynamics model to reduce the yaw angular velocity difference and the lateral deviation between the planned trajectory and the actual driving path of the vehicle, thereby improving the accuracy of the desired yaw moment; and distributes the desired yaw moment to each wheel of the vehicle to maintain the lane change path, thereby better maintaining the vehicle's lane changing function and improving the safety of the vehicle's lane changing process.

[0042] In summary, the present application can maintain the lane changing path by determining the expected yaw torque based on the vehicle dynamics model and distributing it to each wheel of the vehicle when a steering failure occurs in the vehicle, thereby overcoming the technical defects of being unable to maintain the vehicle's lane changing function and poor lane changing safety when the steering system fails during the lane changing process. The application can achieve the goal of maintaining the vehicle's lane changing function when the steering system fails during the lane changing process, thereby improving the safety of the vehicle's lane changing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0045] Figure 1 A flowchart of the first embodiment of the lane change path keeping method of the present application is provided;

[0046] Figure 2 This is a general structural diagram of a planned path keeping algorithm for steering failure of the lane change path keeping method provided in Example 1 of the present application;

[0047] Figure 3 A flow chart of a desired yaw moment distribution strategy for the lane change path keeping method provided in the first embodiment of the present application;

[0048] Figure 4 A schematic diagram of tire force distribution for the lane change path keeping method provided in Example 1 of the present application;

[0049] Figure 5 A flowchart of the second embodiment of the lane change path keeping method of the present application is provided;

[0050] Figure 6 A schematic diagram of a seven-degree-of-freedom vehicle model for the lane change path keeping method provided in Example 2 of the present application;

[0051] Figure 7 This is a schematic diagram of the module structure of the lane change path keeping device according to an embodiment of the present application;

[0052] Figure 8 Schematic diagram of the device structure of the hardware operating environment involved in the lane change path maintenance method in the embodiment of the present application.

[0053] The purpose, features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0054] It should be understood that the specific embodiments described herein are merely used to explain the technical solutions of the present application and are not intended to limit the present application.

[0055] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0056] The main solution of the embodiment of the present application is: when a steering failure occurs in the vehicle, a vehicle dynamics model is constructed; based on the vehicle dynamics model, the desired yaw moment of the vehicle is determined; and the desired yaw moment is distributed to each wheel of the vehicle to maintain the lane change path.

[0057] While using hardware such as the steering system's solenoid valves to address partial steering failures fails to fully utilize the chassis system's capabilities, particularly the impact of the four in-wheel motors on tire forces in four-wheel independent drive electric vehicles (4WDs), it also fails to consider path-keeping capabilities. This results in the vehicle being unable to maintain lane-changing functionality when the steering system fails during a lane change, leading to poor lane-changing safety. Therefore, maintaining lane-changing functionality and improving lane-changing safety during a lane-changing process when the steering system fails is a pressing issue.

[0058] The present application determines the expected yaw torque based on the vehicle dynamics model and distributes it to each wheel of the vehicle when a steering failure occurs in the vehicle, thereby maintaining the lane change path. This overcomes the technical defects of being unable to maintain the vehicle's lane changing function when the steering system fails during the lane changing process, resulting in poor lane changing safety. The application can maintain the vehicle's lane changing function when the steering system fails during the lane changing process, thereby improving the safety of the vehicle's lane changing process.

[0059] It should be noted that the execution subject of this embodiment may be a computing service device with data processing, network communication, and program execution capabilities, such as a tablet computer, personal computer, or mobile phone, or an electronic device capable of implementing the aforementioned functions, such as a lane-changing and path-keeping device. This embodiment and the following embodiments will be described below using the lane-changing and path-keeping device as an example.

[0060] Based on this, the embodiment of the present application provides a lane change path keeping method, referring to Figure 1 , Figure 1 This is a flowchart of the first embodiment of the lane change path keeping method of the present application.

[0061] In this embodiment, the lane change path maintaining method includes steps S10 to S30:

[0062] Step S10, when a steering failure occurs in the vehicle, constructing a vehicle dynamics model;

[0063] It's important to note that if a vehicle experiences a steering failure, such as a steering system failure, it may be unable to change lanes according to the intended path. To maintain the lane change path in this situation, a vehicle dynamics model must first be constructed. This model calculates the vehicle's behavior under specific circumstances, such as the yaw torque required at different speeds and steering angles, based on the vehicle's physical properties, including mass, friction between the tires and the ground, and inertia.

[0064] like Figure 2 As shown, Figure 2 The overall structure of the planned path-keeping algorithm for steering failure is shown in Figure 2. The planned path-keeping algorithm consists of two control loops: an upper controller and a lower controller. In the upper loop controller, the desired yaw moment required during the vehicle's lane change is used as a virtual control variable. In the event of a steering system failure, a combined sliding mode control algorithm is used to calculate the desired yaw moment M, taking both path-keeping and vehicle lateral stability into account. B In the lower loop controller, the weighted least squares control allocation optimization method is used to calculate the desired yaw moment M calculated by the upper controller. B , reasonably distributed to the longitudinal tire force F xi At the same time, under the premise of meeting the expected tire force distribution needs, the constraints of the actuator are considered to decide whether to exit the intelligent driving lane changing function.

[0065] Additionally, it should be noted that to minimize yaw rate differences and lateral deviations between the planned trajectory and the vehicle's actual path, the vehicle dynamics model uses a seven-degree-of-freedom (DOF) model. This model, implemented in the upper-level controller, considers the vehicle's six degrees of freedom: lateral, longitudinal, vertical, yaw, roll, and pitch, as well as the tire's rotational freedom. This model more accurately describes the vehicle's dynamic behavior during lane changes.

[0066] Step S20, determining a desired yaw moment of the vehicle based on the vehicle dynamics model;

[0067] It's important to note that the desired yaw moment is the torque required to maintain the vehicle's intended path. This torque is calculated based on a vehicle dynamics model, incorporating the vehicle's current state (such as speed, acceleration, steering angle, etc.) and information about the target path. Accurately calculating the desired yaw moment ensures that the vehicle can maintain its intended lane change path even if the steering system fails.

[0068] Step S30 : distributing the desired yaw moment to each wheel of the vehicle to maintain the lane change path.

[0069] It should be noted that the four-wheel independent drive electric vehicle (FWID EV) can independently control the driving / braking of each wheel, which makes the vehicle's torque distribution control more flexible compared to traditional fuel vehicles. When the steering system fails, the calculated desired yaw moment M B The lower-level controller uses an optimized distribution strategy to distribute the tire driving force / braking force to the four wheels. At the same time, while meeting the desired tire force distribution requirements, it also considers the actuator constraints, such as the peak torque of the motor.

[0070] like Figure 3 As shown, Figure 3 Flowchart of the desired yaw moment distribution strategy, according to the desired yaw moment M B and the total tire force ∑F to determine whether the constraint conditions are met. If not, the vehicle intelligent driving lane change function will exit directly. If satisfied, the maximum output torque T of the drive motor will be used. max The optimal distribution strategy (i.e., the best strategy) is used to distribute tire forces.

[0071] It can be understood that by reasonably distributing the desired yaw torque to each wheel, appropriate tire force can be generated, thereby helping the vehicle maintain its lane change path when the steering system fails and improving the safety of the vehicle's lane change process.

[0072] In a feasible embodiment, step S30 may include: obtaining the objective function and constraints of tire force distribution; determining the expected longitudinal tire force of each wheel based on the objective function and the constraints; and distributing the expected yaw moment to each wheel of the vehicle according to the expected longitudinal tire force of each wheel.

[0073] It's important to note that the objective function is typically to distribute tire forces as close as possible to the desired distribution, while also considering the vehicle's dynamics and stability. Constraints, such as the maximum tire friction and the maximum motor torque, are determined by the vehicle's dynamics and the physical limitations of the actuators. These constraints ensure that the tire force distribution is within the limits of physical feasibility and actuator capabilities.

[0074] It is understandable that, based on the objective function and the constraints, the expected longitudinal tire force of each wheel can be determined by using various optimization algorithms, such as weighted least squares method, genetic algorithm, etc., to solve the optimal solution of the objective function under the constraints, thereby obtaining the expected longitudinal tire force of each wheel. This embodiment does not impose specific restrictions on this, and this embodiment is illustrated by taking the weighted least squares method as an example.

[0075] It is worth noting that the calculated desired yaw moment is distributed according to the desired longitudinal tire force of each wheel, so that the vehicle can generate appropriate tire forces, thereby helping the vehicle maintain the lane change path when the steering system fails.

[0076] In a feasible embodiment, the objective function and constraint conditions of tire force distribution are obtained, including: obtaining the axle load transfer during vehicle driving, and determining the objective function of tire force distribution based on the axle load transfer during vehicle driving; obtaining the vertical load and tire-road friction coefficient of the vehicle; and determining the constraint conditions of tire force distribution based on the obtained vertical load and tire-road friction coefficient of the vehicle.

[0077] It should be noted that the constraints consist of the constraints on the longitudinal tire forces of the four wheels and the additional constraints on the tire forces. Assuming that the wheelbases of the front and rear axles of the vehicle are both d, in the event of a steering system failure, the constraints on the longitudinal tire forces of the four wheels are as follows:

[0078]

[0079] In formula 1, d is the wheelbase, F xfl 、F xfr 、F xrl and F xrr are the longitudinal forces of the tires of the left front wheel, right front wheel, left rear wheel and right rear wheel, M B is the desired yaw moment, and ∑F is the total tire force.

[0080] The maximum driving torque of a single wheel hub motor is also limited, and the longitudinal force generated by the tire is limited by the vertical load and tire-road friction. The additional constraints on the tire force are as follows:

[0081]

[0082] In formula 2, F xi is the longitudinal force of the tire on wheel i, B i is the additional constraint on the longitudinal force of the tire of wheel i, F m F is the longitudinal force corresponding to the maximum driving torque of the motor. zi is the vertical load on wheel i, μ i is the tire-road friction coefficient.

[0083] Based on the constraints on the longitudinal tire forces of the four wheels and the additional constraints on the tire forces, the constraint conditions are obtained. In the event of steering system failure, if the constraint conditions are met, the tire forces are distributed using an optimization algorithm. Otherwise, the vehicle's intelligent driving lane change function is directly exited. The constraint conditions are as follows:

[0084]

[0085] In Equation 3, B1, B2, B3, and B4 are the additional constraints of the longitudinal tire forces of the four wheels, d is the wheelbase, and M is B is the desired yaw moment, and ∑F is the total tire force.

[0086] It is understandable that in the event of a steering system failure, such as Figure 4 As shown, Figure 4 This is a diagram of tire force distribution. According to the dynamic equation, the yaw moment of the vehicle is expressed as follows:

[0087]

[0088] In formula 4, M B is the desired yaw moment, d is the wheelbase, F xfl 、F xfr 、F xrl and F xrr They are the longitudinal forces of the tires of the left front wheel, right front wheel, left rear wheel, and right rear wheel respectively.

[0089] Considering the real-time driving conditions of the vehicle, based on the actual situation of axle load transfer during vehicle driving, the longitudinal tire force is assumed to be as follows:

[0090]

[0091] In formula 5, F xfl 、F xfr 、F xrl and F xrr are the longitudinal forces of the tires of the left front wheel, right front wheel, left rear wheel and right rear wheel, respectively, F zfl 、F zfr 、F zrl and F zrr are the vertical tire loads of the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively; c1 is the proportional coefficient of the vertical tire load of the left rear wheel to the vertical tire load of the left front wheel; c2 is the proportional coefficient of the vertical tire load of the right rear wheel to the vertical tire load of the right front wheel.

[0092] Based on the above equations 4 and 5, the following equation 6 is obtained:

[0093]

[0094] In formula 6, M B is the desired yaw moment, d is the wheelbase, c1 is the proportionality coefficient of the vertical tire load of the left rear wheel to the vertical tire load of the left front wheel, c2 is the proportionality coefficient of the vertical tire load of the right rear wheel to the vertical tire load of the right front wheel, F xfl 、F xfrare the longitudinal forces of the tires of the left front wheel and the right front wheel respectively.

[0095] Based on the above formula 6, we can get the following formula 7:

[0096] b1Fxfl+b2Fxfr-MB=0 (Equation 7)

[0097] In formula 7, M B is the desired yaw moment, F xfl 、F xfr They are the longitudinal forces of the tires of the left front wheel and the right front wheel, b1 and b2 are F in Eq. xfl 、F xfr The coefficient term of .

[0098] In the case of steering system failure, the optimization algorithm is used to distribute the tire force, and the objective function is established as follows (Equation 8):

[0099]

[0100] In Equation 8, J is the objective function, F xfl 、F xfr are the longitudinal forces of the tires of the left front wheel and the right front wheel, respectively. ψ represents the weight coefficient, which coordinates the participation of the left front wheel driving force and the right front wheel in the yaw moment distribution.

[0101] The tire longitudinal force obtained by the optimization algorithm is obtained by applying the Lagrange multiplier method based on the objective function and constraints of the optimization algorithm, as shown in Equation 9:

[0102]

[0103] In formula 9, F xfl 、F xfr They are the longitudinal forces of the left and right front wheels respectively, ψ represents the weight coefficient, M B is the desired yaw moment.

[0104] After calculating the optimal left and right front wheel longitudinal tire forces using Equation 9, the optimal left and right rear wheel longitudinal tire forces can be calculated using Equation 5. The desired yaw moment is distributed based on the optimal left, right, and left rear wheel longitudinal tire forces.

[0105] This embodiment provides a lane change path maintenance method. This embodiment first constructs a vehicle dynamics model when a steering failure occurs in the vehicle to facilitate improving computational efficiency; determines a desired yaw moment of the vehicle based on the vehicle dynamics model to reduce the yaw angular velocity difference and the lateral deviation between the planned trajectory and the vehicle's actual driving path, thereby improving the accuracy of the desired yaw moment; and distributes the desired yaw moment to each wheel of the vehicle to maintain the lane change path, thereby better maintaining the vehicle's lane change function and improving the safety of the vehicle's lane change process.

[0106] In summary, this embodiment can maintain the lane change path by determining the expected yaw torque based on the vehicle dynamics model and distributing it to each wheel of the vehicle when a steering failure occurs in the vehicle. This overcomes the technical defects of being unable to maintain the vehicle's lane changing function and poor lane changing safety when the steering system fails during the lane changing process. It can achieve the goal of maintaining the vehicle's lane changing function when the steering system fails during the lane changing process, thereby improving the safety of the vehicle's lane changing process.

[0107] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above embodiment 1 can be referred to the above introduction and will not be described in detail later. Figure 5 , the step S20 further includes steps S201-S204:

[0108] Step S201 : Control the vehicle dynamics model to perform yaw motion to obtain a vehicle dynamics relationship.

[0109] It should be noted that by adjusting the parameters of the vehicle dynamics model and simulating the yaw motion of the vehicle during lane change, we can gain a deeper understanding of the vehicle's dynamic characteristics during actual driving, including vehicle stability, handling, and the interaction between the tires and the ground.

[0110] It can be understood that in the event of a steering system failure, in order to continue driving along the planned lane change path while taking vehicle stability into consideration, a sliding mode control method is used to obtain the desired yaw moment MB required for yaw rate error control and lateral deviation control between the planned trajectory and the actual vehicle driving path.

[0111] It is worth noting that in order to reduce the yaw rate difference and the lateral deviation between the planned trajectory and the actual driving path of the vehicle, a seven-degree-of-freedom vehicle model is used in the upper controller, that is, the vehicle dynamics model is a seven-degree-of-freedom vehicle model, such as Figure 6 As shown, Figure 6 is a schematic diagram of a seven-degree-of-freedom vehicle model. The dynamic equation of the yaw motion of the seven-degree-of-freedom vehicle model is as follows:

[0112]

[0113] In Equation 10, γ is the yaw rate, v x represents the longitudinal velocity of the vehicle, F yfl 、F yfr 、F yrl and F yrr are the tire lateral forces of the left front wheel, right front wheel, left rear wheel, and right rear wheel, I z is the inertia moment of the vehicle in the yaw direction around the Z axis, l f and l r Represents the distance from the front axle and rear axle to the center of mass, M B Represents the desired yaw moment of the vehicle.

[0114] Step S202 : Acquire vehicle driving parameters, and determine the yaw rate difference and the trajectory lateral deviation according to the vehicle driving parameters.

[0115] It should be noted that vehicle driving parameters include but are not limited to vehicle speed, acceleration, and yaw rate. These parameters can be monitored and acquired in real time by the vehicle's sensors. Based on these parameters, the yaw rate difference and lateral trajectory deviation can be calculated. The yaw rate difference refers to the difference between the vehicle's actual yaw rate and the desired yaw rate, reflecting the vehicle's stability. The lateral trajectory deviation refers to the lateral distance difference between the vehicle's actual driving path and the planned trajectory, reflecting whether the vehicle is traveling along the intended path.

[0116] In a feasible embodiment, the vehicle driving parameters include the tire lateral stiffness of the front wheels of the vehicle, the tire lateral stiffness of the rear wheels, the front wheel steering angle, and the actual yaw rate of the vehicle; step S202 may include: calculating according to the tire lateral stiffness of the front wheels of the vehicle, the tire lateral stiffness of the rear wheels, and the front wheel steering angle to obtain a reference yaw rate of the vehicle; and determining a yaw rate difference according to the actual yaw rate and the reference yaw rate.

[0117] It should be noted that the reference yaw angular velocity is as follows:

[0118]

[0119] In Equation 11, γ d is the reference yaw rate, C f and C r Represent the tire cornering stiffness of the front and rear wheels respectively, δ f is the front wheel steering angle of the vehicle, v x represents the longitudinal velocity of the vehicle, l f and l r Represent the distance from the front axle and rear axle to the center of mass respectively, and m is the weight of the vehicle.

[0120] Tire lateral force F yf 、F yr The calculation is as follows:

[0121] Fyf=-Cfαf, Fyr=-Crαr (Formula 12)

[0122] In formula 12, F yf is the lateral force of the front tire, F yr is the lateral force of the rear tire, C f and C r Represents the tire cornering stiffness of the front and rear wheels respectively, α f and α r They represent the front wheel slip angle and rear wheel slip angle respectively.

[0123] In a feasible embodiment, the vehicle driving parameters also include the longitudinal speed of the vehicle; step S202 may also include: determining the actual driving path of the vehicle based on the longitudinal speed of the vehicle and the actual yaw angular velocity; determining the lateral deviation of the trajectory based on the actual driving path of the vehicle and the preset planned driving path.

[0124] It should be noted that the vehicle trajectory during driving is y', which is calculated as follows:

[0125]

[0126]

[0127] In Equations 13 and 14, y' is the trajectory of the vehicle, γ is the yaw rate, and v x Represents the longitudinal velocity of the vehicle.

[0128] The lateral deviation between the planned trajectory and the actual vehicle path can be obtained as follows:

[0129] Δy=y'-y (Equation 15)

[0130] In Equation 15, Δy is the lateral deviation of the trajectory, y' is the ego vehicle trajectory, and y is the planned trajectory of the vehicle during the lane change process.

[0131] Step S203 : determining a sliding mode surface based on the yaw angular velocity difference and the trajectory lateral deviation.

[0132] It's important to note that the sliding surface determines the trajectory of the system's state during sliding mode motion. Based on the yaw rate difference and the lateral trajectory deviation, combined with sliding mode control theory, a sliding surface can be constructed. The design of the sliding surface must meet certain conditions to ensure stable sliding motion on the surface, thereby effectively controlling the yaw rate error and lateral trajectory deviation.

[0133] It can be understood that when the steering system fails, taking into full account the yaw rate difference and the lateral deviation between the planned trajectory and the actual driving path of the vehicle, the sliding surface S is as follows:

[0134] S=γ-γ d +ξ·Δy(ξ>0) (Equation 16)

[0135] In Equation 16, S is the sliding surface, γ d is the reference yaw rate, γ is the actual yaw rate, γ-γ d is the yaw rate difference, and Δy is the lateral deviation of the trajectory.

[0136] Step S204 : determining a desired yaw moment of the vehicle according to the sliding surface and the vehicle dynamics relationship.

[0137] It's important to note that the vehicle's desired yaw moment is calculated based on the relationship between the sliding surface and vehicle dynamics. Sliding mode control theory requires that the system state slide along the sliding surface, and the desired yaw moment is the torque required to achieve this sliding motion. Based on vehicle dynamics, the desired yaw moment can be solved by taking the derivative of the sliding surface and combining it with the vehicle's dynamic equations.

[0138] Specifically, the desired yaw moment is calculated as follows: First, the sliding mode surface S is differentiated to obtain its derivative. Then, based on the vehicle's dynamic equations, S' is related to vehicle dynamic parameters (such as vehicle mass and tire cornering stiffness) to derive an expression for the desired yaw moment. This expression serves as a control input to adjust the vehicle's steering system to achieve sliding mode motion, thereby reducing yaw rate difference and lateral trajectory deviation, thereby improving vehicle stability and driving safety.

[0139] It's important to note that the calculation of the desired yaw moment must fully consider the vehicle's actual driving state and dynamic characteristics to ensure the effectiveness and feasibility of the control input. Furthermore, the desired yaw moment must be limited to prevent damage to the vehicle due to excessive control input. In practice, the calculated desired yaw moment can be optimized by adjusting parameters in the control algorithm to meet control requirements in different scenarios.

[0140] In a feasible implementation, step S204 may include: performing calculations based on the sliding surface to obtain a reaching law; and determining a desired yaw moment of the vehicle based on the reaching law and the vehicle dynamics relationship.

[0141] It should be noted that selecting the constant velocity reaching law as the reaching law of the sliding mode control algorithm can ensure that the system state reaches the sliding mode surface within a finite time and realizes the sliding mode motion. The expression of the constant velocity reaching law is as follows:

[0142]

[0143] In Equation 17, η represents a suitable positive value to approach the sliding surface at a faster speed and achieve the desired stable state.

[0144] The derivative of the sliding surface is obtained by taking the derivative of the sliding surface, as shown in Equation 18:

[0145]

[0146] According to the relationship between the constant velocity approaching law and vehicle dynamics, the desired yaw moment of the vehicle can be solved. That is, the expression of the constant velocity approaching law is substituted into the derivative of the sliding surface, and combined with the vehicle dynamics equation, the desired yaw moment M can be solved. B The expression is as follows:

[0147]

[0148] In formula 19, M B represents the desired yaw moment, η represents an appropriate positive value, F yfl 、F yfr 、F yrl and F yrr are the tire lateral forces of the left front wheel, right front wheel, left rear wheel, and right rear wheel, I z is the inertia moment of the vehicle in the yaw direction around the Z axis, l f and l r Represents the distance from the front axle and rear axle to the center of mass, γ d is the reference yaw rate, and Δy is the lateral deviation of the trajectory.

[0149] In order to avoid the jitter effect caused by frequent switching of the system near the sliding surface, the thickness of the sliding surface is used. The continuous approximation of is used to smooth the discontinuity of system control. Therefore, the desired yaw moment required can be expressed as follows:

[0150]

[0151] In Equation 20, M B represents the desired yaw moment, η represents a suitable positive value, S is the sliding surface, is the thickness near the sliding surface.

[0152] In this embodiment, the desired yaw moment of the vehicle is determined by using the vehicle dynamics relationship obtained by performing yaw motion according to the control vehicle dynamics model and the sliding surface determined based on the yaw angular velocity difference and the lateral trajectory deviation. This facilitates adjustment of the vehicle's steering system to achieve sliding mode motion, thereby reducing the yaw angular velocity difference and the lateral trajectory deviation and improving the vehicle's stability and driving safety.

[0153] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the lane change path keeping method of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0154] This application also provides a lane change path maintaining device, please refer to Figure 7 , the lane change path maintaining device includes:

[0155] The construction module 10 is used to construct a vehicle dynamics model when a steering failure occurs in the vehicle.

[0156] The determination module 20 is configured to determine a desired yaw moment of the vehicle based on the vehicle dynamics model.

[0157] The distribution module 30 is configured to distribute the desired yaw moment to each wheel of the vehicle to maintain a lane change path.

[0158] This embodiment provides a lane change path maintaining device. This embodiment first constructs a vehicle dynamics model when a steering failure occurs in the vehicle to facilitate improving computational efficiency; determines a desired yaw moment of the vehicle based on the vehicle dynamics model to reduce the yaw angular velocity difference and the lateral deviation between the planned trajectory and the vehicle's actual driving path, thereby improving the accuracy of the desired yaw moment; and distributes the desired yaw moment to each wheel of the vehicle to maintain the lane change path, thereby better maintaining the vehicle's lane changing function and improving the safety of the vehicle's lane changing process.

[0159] In summary, this embodiment can maintain the lane change path by determining the expected yaw torque based on the vehicle dynamics model and distributing it to each wheel of the vehicle when a steering failure occurs in the vehicle. This overcomes the technical defects of being unable to maintain the vehicle's lane changing function and poor lane changing safety when the steering system fails during the lane changing process. It can achieve the goal of maintaining the vehicle's lane changing function when the steering system fails during the lane changing process, thereby improving the safety of the vehicle's lane changing process.

[0160] Optionally, the determination module 20 is further used to control the vehicle dynamics model to perform yaw motion to obtain a vehicle dynamics relationship; obtain vehicle driving parameters, and determine a yaw angular velocity difference and a lateral deviation of a trajectory based on the vehicle driving parameters; determine a sliding surface based on the yaw angular velocity difference and the lateral deviation of the trajectory; and determine a desired yaw moment of the vehicle based on the sliding surface and the vehicle dynamics relationship.

[0161] Optionally, the vehicle driving parameters include the tire lateral stiffness of the front wheels, the tire lateral stiffness of the rear wheels, the front wheel steering angle, and the actual yaw rate of the vehicle; the determination module 20 is further used to calculate based on the tire lateral stiffness of the front wheels, the tire lateral stiffness of the rear wheels, and the front wheel steering angle to obtain a reference yaw rate of the vehicle; and determine a yaw rate difference based on the actual yaw rate and the reference yaw rate.

[0162] Optionally, the vehicle driving parameters also include the longitudinal speed of the vehicle; the determination module 20 is further used to determine the actual driving path of the vehicle based on the longitudinal speed of the vehicle and the actual yaw angular velocity; and determine the lateral deviation of the trajectory based on the actual driving path of the vehicle and the preset planned driving path.

[0163] Optionally, the determination module 20 is further configured to perform calculations based on the sliding surface to obtain a reaching law; and determine a desired yaw moment of the vehicle based on the reaching law and the vehicle dynamics relationship.

[0164] Optionally, the distribution module 30 is further used to obtain the objective function and constraints of tire force distribution; determine the expected longitudinal tire force of each wheel based on the objective function and the constraints; and distribute the expected yaw moment to each wheel of the vehicle according to the expected longitudinal tire force of each wheel.

[0165] Optionally, the distribution module 30 is further used to obtain the axle load transfer during vehicle driving, and determine the objective function of tire force distribution based on the axle load transfer during vehicle driving; obtain the vertical load and tire-road friction coefficient of the vehicle; and determine the constraint conditions of tire force distribution based on the obtained vertical load and tire-road friction coefficient of the vehicle.

[0166] The lane-changing path-keeping device provided in this application utilizes the lane-changing path-keeping method described in the aforementioned embodiments to address the technical issues surrounding lane-changing path-keeping. Compared to the prior art, the lane-changing path-keeping device provided in this application achieves the same beneficial effects as the lane-changing path-keeping method described in the aforementioned embodiments. Other technical features of the lane-changing path-keeping device are the same as those disclosed in the aforementioned embodiments and are not further elaborated here.

[0167] The present application provides a lane-changing path-keeping device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the lane-changing path-keeping method in the above-mentioned embodiment 1.

[0168] Reference below Figure 8 , which shows a schematic structural diagram of a lane-changing path-keeping device suitable for implementing an embodiment of the present application. The lane-changing path-keeping device in the embodiment of the present application may include, but is not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), in-vehicle terminals (e.g., in-vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 5 The lane change path keeping device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0169] like Figure 8 As shown, the lane-changing path-keeping device may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can execute various appropriate actions and processes based on programs stored in a read-only memory (ROM) 1002 or programs loaded from a storage device 1003 into a random access memory (RAM) 1004. RAM 1004 also stores various programs and data required for the operation of the lane-changing path-keeping device. Processing device 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems may be connected to I / O interface 1006: input device 1007 including, for example, a touchscreen, touchpad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; output device 1008 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; storage device 1003 including, for example, a magnetic tape, hard disk, etc.; and communication device 1009. Communication device 1009 can allow the lane-changing path-keeping device to communicate with other devices wirelessly or wired to exchange data. Although the figure shows a lane-changing path-keeping device with various systems, it should be understood that it is not required to implement or have all of the systems shown. More or fewer systems may be implemented or have alternatively.

[0170] In particular, according to the embodiments disclosed in the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments disclosed in the present application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program comprising program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0171] The lane-changing path-keeping device provided in this application utilizes the lane-changing path-keeping method described in the aforementioned embodiment to address the technical issues surrounding lane-changing path-keeping. Compared to the prior art, the lane-changing path-keeping device provided in this application achieves the same beneficial effects as the lane-changing path-keeping method described in the aforementioned embodiment. Other technical features of the lane-changing path-keeping device are the same as those disclosed in the aforementioned embodiment and are not further elaborated here.

[0172] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0173] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0174] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, a computer program) stored thereon, and the computer-readable program instructions are used to execute the lane change path keeping method in the above embodiment.

[0175] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0176] The computer-readable storage medium may be included in the lane-changing path keeping device, or may exist independently without being incorporated into the lane-changing path keeping device.

[0177] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the lane change path maintaining device, the lane change path maintaining device: constructs a vehicle dynamics model when a steering failure occurs in the vehicle; determines a desired yaw moment of the vehicle based on the vehicle dynamics model; and distributes the desired yaw moment to each wheel of the vehicle to maintain the lane change path.

[0178] Computer program code for performing the operations of the present application may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages such as Java, Smalltalk, C++, and conventional procedural programming languages such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0179] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, program segment or a part of code, and the module, program segment or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0180] The modules described in the embodiments of the present application may be implemented in software or hardware, wherein the name of a module does not necessarily limit the unit itself.

[0181] The computer-readable storage medium provided in this application stores computer-readable program instructions (i.e., a computer program) for executing the lane-changing path-keeping method described above, thereby resolving the technical issues surrounding lane-changing path-keeping. Compared to the prior art, the computer-readable storage medium provided in this application offers the same beneficial effects as the lane-changing path-keeping method provided in the aforementioned embodiments, and therefore will not be further elaborated upon here.

[0182] The present application also provides a computer program product, including a computer program, which implements the steps of the lane change path keeping method as described above when the computer program is executed by a processor.

[0183] The computer program product provided in this application can solve the technical problem of lane change path keeping. Compared with the existing technology, the beneficial effects of the computer program product provided in this application are the same as the beneficial effects of the lane change path keeping method provided in the above embodiment, and will not be repeated here.

[0184] The above description is only part of the embodiments of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A lane change path keeping method, characterized in that: The method comprises: When a steering failure occurs in the vehicle, a vehicle dynamics model is constructed, wherein the vehicle dynamics model is a seven-degree-of-freedom vehicle model, and the seven degrees of freedom of the vehicle model include six degrees of freedom of the vehicle: lateral, longitudinal, vertical, yaw, roll, and pitch, and a rotational degree of freedom of the tires; determining a desired yaw moment of the vehicle based on the vehicle dynamics model; Determining a desired yaw moment of the vehicle based on the vehicle dynamics model includes: controlling the vehicle dynamics model to perform yaw motion to obtain a vehicle dynamics relationship; Acquiring vehicle driving parameters, and determining a yaw rate difference and a trajectory lateral deviation based on the vehicle driving parameters; determining a sliding mode surface based on the yaw rate difference and the trajectory lateral deviation; determining a desired yaw moment of the vehicle based on the sliding surface and the vehicle dynamics relationship; The vehicle driving parameters also include the longitudinal speed of the vehicle; Determining the trajectory lateral deviation according to the vehicle driving parameters includes: determining an actual driving path of the vehicle based on the longitudinal velocity and the actual yaw rate of the vehicle; Determining a lateral deviation of a trajectory based on the actual driving path of the vehicle and a preset planned driving path; distributing the desired yaw moment to each wheel of the vehicle to maintain a lane change path; The step of distributing the desired yaw moment to each wheel of the vehicle includes: Obtain the objective function and constraints of tire force distribution; determining a desired longitudinal tire force for each wheel based on the objective function and the constraints; The desired yaw moment is distributed to each wheel of the vehicle according to the desired longitudinal tire force of each wheel.

2. The method according to claim 1, wherein The vehicle driving parameters include the tire cornering stiffness of the front wheels, the tire cornering stiffness of the rear wheels, the front wheel steering angle, and the actual yaw rate of the vehicle; The determining the yaw rate difference according to the vehicle driving parameters includes: Calculating according to the tire cornering stiffness of the front wheels of the vehicle, the tire cornering stiffness of the rear wheels, and the front wheel steering angle to obtain a reference yaw rate of the vehicle; A yaw rate difference is determined based on the actual yaw rate and the reference yaw rate.

3. The method according to claim 1, wherein Determining the desired yaw moment of the vehicle according to the sliding mode surface and the vehicle dynamics relationship includes: Calculating according to the sliding surface to obtain a reaching law; A desired yaw moment of the vehicle is determined based on the reaching law and the vehicle dynamics relationship.

4. The method according to claim 1, wherein The objective function and constraint conditions for obtaining tire force distribution include: Acquiring an axle load transfer condition during vehicle travel, and determining an objective function for tire force distribution based on the axle load transfer condition during vehicle travel; Obtain the vehicle's vertical load and tire-road friction coefficient; The constraint conditions of tire force distribution are determined based on the obtained vertical load of the vehicle and the tire-road friction coefficient.

5. A lane change path keeping device, characterized in that: The lane change path maintaining device includes: A construction module is used to construct a vehicle dynamics model when a steering failure occurs in the vehicle, wherein the vehicle dynamics model is a vehicle model with seven degrees of freedom, including six degrees of freedom of the vehicle: lateral, longitudinal, vertical, yaw, roll, and pitch, and a rotational degree of freedom of the tires; a determination module, configured to determine a desired yaw moment of the vehicle based on the vehicle dynamics model; a distribution module, configured to distribute the desired yaw moment to each wheel of the vehicle to maintain a lane change path; The determination module is further configured to control the vehicle dynamics model to perform yaw motion to obtain a vehicle dynamics relationship; obtain vehicle driving parameters and determine a yaw rate difference and a lateral trajectory deviation based on the vehicle driving parameters; determine a sliding mode surface based on the yaw rate difference and the lateral trajectory deviation; and determine a desired yaw moment of the vehicle based on the sliding mode surface and the vehicle dynamics relationship; The determination module is further configured to determine an actual driving path of the vehicle based on the longitudinal velocity and the actual yaw angular velocity of the vehicle; and determine a lateral deviation of the trajectory based on the actual driving path of the vehicle and a preset planned driving path; The distribution module is further used to obtain the objective function and constraints of tire force distribution; determine the expected longitudinal tire force of each wheel based on the objective function and the constraints; and distribute the expected yaw moment to each wheel of the vehicle according to the expected longitudinal tire force of each wheel.

6. A lane change path keeping device, characterized in that: The lane-changing path keeping device includes: a memory, a processor, and a lane-changing path keeping program stored in the memory and executable on the processor, wherein the lane-changing path keeping program is configured to implement the lane-changing path keeping method according to any one of claims 1 to 4.

7. A storage medium, characterized in that: The storage medium stores a lane-changing path keeping program, which, when executed by a processor, implements the lane-changing path keeping method according to any one of claims 1 to 4.

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