Lane deviation rectification track generation method, device and equipment and storage medium

Abstract

The invention discloses a lane deviation rectification track generation method, device and equipment and a storage medium, and relates to the technical field of vehicle track planning, and the lane deviation rectification track generation method comprises the steps that when it is detected that a lane deviation rectification function of a vehicle is activated, the longitudinal speed, the current time and the initial transverse speed of the vehicle are obtained; constructing a quintic polynomial according to the longitudinal velocity, the current time and the initial transverse velocity; obtaining a target coefficient of the quintic polynomial according to the quintic polynomial and an optimization target function; and generating a correction track according to the quintic polynomial and the target coefficient. And by constructing a quintic polynomial and combining with an optimized objective function, generating a lane deviation correction track meeting smoothness and control requirements, and realizing automatic deviation correction of the vehicle.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle trajectory planning, and in particular to a lane correction trajectory generation method, device, equipment and storage medium. Background Art

[0002] In autonomous driving and assisted driving systems, the lane correction function of a vehicle requires that the vehicle can automatically generate a smooth and accurate regression trajectory when it detects lane deviation, thereby safely guiding the vehicle back to the centerline of the lane. This trajectory generation process needs to consider the real-time motion state of the vehicle, such as longitudinal speed, lateral speed, etc., and generate a trajectory that satisfies lateral smoothness and reasonable speed changes to ensure the stability of the correction process and ride comfort.

[0003] At present, most traditional lane correction trajectory generation methods rely on simple geometric programming or low-order polynomial models, and only generate trajectories based on the starting and ending states of the vehicle, without fully considering the change control of the vehicle's speed and acceleration during the correction process. This method has deficiencies in stability and accuracy, especially when dealing with lateral acceleration and jerk, which can easily lead to uneven trajectories, which in turn cause the vehicle to vibrate or move unnaturally during correction.

[0004] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of this application is to provide a lane correction trajectory generation, device, equipment and storage medium, aiming to solve the technical problem that the lane correction trajectory generation method lacks optimized control of lateral position, acceleration and jerk, and it is difficult to achieve a smooth and accurate correction trajectory.

[0006] To achieve the above objectives, the present application proposes a lane correction trajectory generation method, the method comprising:

[0007] When it is detected that the lane deviation correction function of the vehicle is activated, obtaining the longitudinal speed, current time and initial lateral speed of the vehicle;

[0008] constructing a fifth-order polynomial according to the longitudinal velocity, the current time, and the initial lateral velocity;

[0009] According to the quintic polynomial and the optimization objective function, obtaining the target coefficient of the quintic polynomial;

[0010] A deviation correction trajectory is generated according to the quintic polynomial and the target coefficient.

[0011] In one embodiment, the step of obtaining the target coefficient of the quintic polynomial according to the quintic polynomial and the optimization objective function comprises:

[0012] Construct the optimization objective function based on the quintic polynomial;

[0013] constraining the quintic polynomial according to the optimization objective function;

[0014] The optimization objective function is converted into a quadratic programming problem, and the quadratic programming problem is solved to obtain the objective coefficients of the quintic polynomial.

[0015] In one embodiment, the step of constructing an optimization objective function according to a quintic polynomial comprises:

[0016] Obtaining a target lateral velocity, a target lateral acceleration, a target lateral jerk, and a weight coefficient of a quintic polynomial;

[0017] constructing an optimization objective function according to the target lateral velocity, the target lateral acceleration, the target lateral jerk, and the weight coefficient;

[0018] The step of constraining the quintic polynomial according to the optimization objective function comprises:

[0019] Obtaining constraint conditions according to the optimization objective function;

[0020] A constraint condition is obtained according to the optimization objective function, and the constraint condition is applied to a quintic polynomial.

[0021] In one embodiment, the step of converting the optimization objective function into a quadratic programming problem and solving the quadratic programming problem to obtain the target coefficient of the quintic polynomial includes:

[0022] Construct the matrix of the quadratic programming problem and obtain the Hessian matrix;

[0023] The Hessian matrix and the optimization objective function constraint condition are combined to obtain the objective constraint condition;

[0024] According to the target constraint condition and the Hessian matrix, the target coefficients of the quintic polynomial are obtained.

[0025] In one embodiment, the step of constructing a quintic polynomial according to the longitudinal velocity, the current time and the initial lateral velocity comprises:

[0026] Constructing a lateral displacement time function according to the polynomial coefficients and the current time;

[0027] constructing a longitudinal displacement time function according to the initial lateral velocity and the current time;

[0028] According to the lateral displacement time function, a target lateral velocity, a target lateral acceleration and a lateral jerk are obtained;

[0029] A boundary condition is constructed according to the initial lateral velocity, and a quintic polynomial is constructed according to the boundary condition.

[0030] In one embodiment, the step of constructing a boundary condition according to the initial lateral velocity and constructing a quintic polynomial according to the boundary condition comprises:

[0031] Obtaining an initial lateral displacement, a target lateral displacement, a target lateral velocity, and a target lateral acceleration of the vehicle;

[0032] constructing a boundary condition based on the initial lateral velocity, the initial lateral displacement, the target lateral displacement, the target lateral velocity, and the target lateral acceleration;

[0033] generating a target set of equations according to the boundary conditions;

[0034] The target coefficients of the quintic polynomial are solved according to the target equation group.

[0035] In one embodiment, the step of constructing the boundary condition according to the initial lateral velocity, the initial lateral displacement, the target lateral displacement, the target lateral velocity and the target lateral acceleration comprises:

[0036] constructing a starting condition based on the initial lateral displacement and the initial lateral velocity;

[0037] Establishing a termination condition according to the target lateral displacement, the target lateral velocity, and the target lateral acceleration;

[0038] The boundary conditions are constructed according to the starting conditions and the ending conditions.

[0039] In addition, to achieve the above-mentioned purpose, the present application also proposes a lane correction trajectory generation device, the lane correction trajectory generation device comprising: an acquisition module, for acquiring the longitudinal speed, current time and initial lateral speed of the vehicle when the lane correction function of the vehicle is detected to be activated;

[0040] A construction module, configured to construct a quintic polynomial according to the longitudinal velocity, the current time and the initial lateral velocity;

[0041] An obtaining module, used for obtaining target coefficients of the quintic polynomial according to the quintic polynomial and an optimization target function;

[0042] A generation module is used to generate a correction trajectory according to the quintic polynomial and the target coefficient.

[0043] In addition, to achieve the above-mentioned purpose, the present application also proposes a lane correction trajectory generation device, which includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, and the computer program is configured to implement the steps of the lane correction trajectory generation method described above.

[0044] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by the processor, the steps of the lane correction trajectory generation method described above are implemented.

[0045] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it implements the steps of the lane correction trajectory generation method described above.

[0046] One or more technical solutions proposed in this application have at least the following technical effects:

[0047] By constructing a quintic polynomial based on the vehicle longitudinal speed, current time and initial lateral speed, and determining the target coefficient of the polynomial in combination with the optimization objective function, a correction trajectory that meets the smoothness and control requirements is generated. This effectively solves the problem in the prior art that it is difficult to generate a smooth trajectory when dynamically adjusting the lateral speed and acceleration. Compared with the prior art, this method can adaptively generate a smooth correction path under different starting conditions, effectively reducing the lateral acceleration and jerk changes, and improving the trajectory smoothness and stability of the correction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] 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.

[0049] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0050] Figure 1 A flowchart diagram of the first embodiment of the lane correction trajectory generation method of the present application is provided;

[0051] Figure 2 A schematic diagram of a correction coordinate system provided in Example 1 of the lane correction trajectory generation method of the present application;

[0052] Figure 3A flow chart of the second embodiment of the lane deviation correction trajectory generation method provided in the present application;

[0053] Figure 4 This is a schematic diagram of the module structure of the lane deviation correction trajectory generation device according to an embodiment of the present application;

[0054] Figure 5 Schematic diagram of the device structure of the hardware operating environment involved in the lane correction trajectory generation method in the embodiment of the present application.

[0055] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0056] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0057] 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.

[0058] The main solution of the embodiment of the present application is: when it is detected that the lane deviation correction function of the vehicle is activated, the longitudinal speed, current time and initial lateral speed of the vehicle are obtained;

[0059] constructing a fifth-order polynomial according to the longitudinal velocity, the current time, and the initial lateral velocity;

[0060] According to the quintic polynomial and the optimization objective function, obtaining the target coefficient of the quintic polynomial;

[0061] A deviation correction trajectory is generated according to the quintic polynomial and the target coefficient.

[0062] In this embodiment, for ease of description, the following description is made by taking the lane deviation correction trajectory generation device as the execution subject.

[0063] Since the prior art lane correction trajectory generation method lacks optimized control of lateral position, acceleration and jerk, it is difficult to achieve a smooth and accurate correction trajectory. The present application provides a solution by constructing a quintic polynomial based on the longitudinal speed of the vehicle, the current time and the initial lateral speed, and determining the target coefficient of the polynomial in combination with the optimization objective function to generate a correction trajectory that meets the smoothness and control requirements. The problem that it is difficult to generate a smooth trajectory under the condition of dynamically adjusting the lateral speed and acceleration in the prior art is effectively solved. Compared with the prior art, the present method can adaptively generate a smooth correction path under different starting conditions, effectively reducing the changes in lateral acceleration and jerk, and improving the trajectory smoothness and stability of the correction process.

[0064] It should be noted that the execution subject of this embodiment may be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an electronic device capable of realizing the above functions, a lane correction trajectory generation device, etc. The following takes the lane correction trajectory generation device as an example to illustrate this embodiment and the following embodiments.

[0065] Based on this, the present application embodiment provides a lane correction trajectory generation method, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the lane correction trajectory generation method of the present application.

[0066] In this embodiment, the lane deviation correction trajectory generation method includes steps S10 to S40:

[0067] Step S10, when it is detected that the lane deviation correction function of the vehicle is activated, obtaining the longitudinal speed, current time and initial lateral speed of the vehicle;

[0068] It should be noted that the lane correction function usually refers to an auxiliary function that uses automatic control technology to return the vehicle to the center of the lane when the vehicle deviates from the lane unconsciously. When sensors, such as cameras or radars, detect that the vehicle deviates from the center of the lane within a certain range, the function is automatically activated to guide the vehicle back to the lane. The current time refers to the time point when the vehicle detects that the correction function is activated, which is used to control the duration and time segmentation of the correction process in subsequent trajectory generation.

[0069] Reference Figure 2 , Figure 2 Schematic diagram of the correction coordinate system of the first embodiment of the lane correction trajectory generation method of the present application.

[0070] like Figure 2 As shown in the figure, when the intelligent vehicle makes an unintentional deviation and makes a correction, a rectangular coordinate system is established with the midpoint of the front axle of the vehicle as the origin at the initial activation moment, the longitudinal axis of the vehicle as the x-axis, perpendicular to the lane line and the left hand direction of the vehicle as the positive direction of the y-axis. The initial position of the vehicle deviating from the lane is marked as S1, and its parameters include time t0, lateral displacement d0, and initial lateral velocity v0. At this time, the vehicle begins to deviate from the lane and activates the lane correction function. The target position of the vehicle is marked as S2, and its parameters include time t1, target lateral displacement d1, terminal lateral velocity v1, and target lateral acceleration a1. This point indicates that the vehicle has successfully corrected and returned to the end position of the lane line. The blue curve represents the correction trajectory of the vehicle from the deviation position S1 to the lane center S2. The trajectory is constructed by a quintic polynomial, taking into account factors such as the starting and ending lateral velocities and accelerations, ensuring the smoothness and safety of the trajectory.

[0071] In addition, it should be noted that the longitudinal speed refers to the speed of the vehicle along the direction of travel, that is, Figure 2 The x-axis direction in the correction process. During the correction process, the longitudinal speed of the vehicle affects the smoothness of the trajectory generation and the difficulty of control. At high speeds, the correction trajectory needs to be smoother to reduce the discomfort caused by the vehicle's lateral movement. The initial lateral speed refers to the speed of the vehicle moving along the y-axis direction, that is, perpendicular to the lane when the correction function is activated. The initial lateral speed reflects the current deviation trend of the vehicle. By recording the initial lateral speed, the initial conditions of the polynomial can be defined.

[0072] Step S20, constructing a quintic polynomial according to the longitudinal velocity, the current time and the initial lateral velocity;

[0073] It should be noted that the quintic polynomial is a high-order polynomial with six coefficients, which is used to describe the changes of the vehicle's lateral displacement and longitudinal displacement over time t. The degree of freedom of the quintic polynomial is high enough to meet the boundary conditions of the vehicle's lateral displacement, velocity and acceleration, and generate a smooth curve. During the construction process, the longitudinal velocity, current time and initial lateral velocity are used as initial conditions to determine the shape of the polynomial, so that it can adapt to the vehicle's driving state and ensure the stability and smoothness of the correction process.

[0074] Step S30, obtaining target coefficients of the quintic polynomial according to the quintic polynomial and the optimization objective function;

[0075] It should be noted that the optimization objective function is a mathematical tool used to ensure that the correction trajectory meets the smoothness requirements during the control process. Usually, the objective function will include weighted control of lateral displacement, lateral acceleration and jerk. The purpose of the optimization objective function is to minimize the weighted sum of these factors so that the vehicle can smoothly return to the lane during the correction process and avoid sudden changes in motion. The target coefficient refers to the final coefficient determined in the quintic polynomial used to generate the correction trajectory. The target coefficient is calculated by the optimization algorithm under the premise of satisfying the current state of the vehicle, such as lateral velocity and position, and boundary conditions, such as target position, velocity, and acceleration, to ensure that the generated trajectory meets the requirements of smoothness, comfort and control.

[0076] It is understood that an optimization problem can be formed by substituting the quintic polynomial into the optimization objective function and combining boundary conditions, such as the lateral displacement, velocity and acceleration of the starting point and the end point. The optimization problem is solved using an optimization algorithm, such as a quadratic programming algorithm, to determine the target coefficients of the polynomial.

[0077] In a feasible implementation, step S30 may include steps S31 to S33:

[0078] Step S31, constructing an optimization objective function according to a quintic polynomial;

[0079] It is understandable that the purpose of constructing the optimization objective function is to control the range of lateral displacement, acceleration and jerk in the process of generating the trajectory, so as to avoid violent shaking or uncomfortable movement of the vehicle during the correction process. By setting different weights, specific parameters can be optimized first according to actual needs, such as stability requirements, to generate a trajectory that better meets driving requirements.

[0080] In a feasible implementation, step S31 may include steps S311 to S312:

[0081] Step S311, obtaining a target lateral velocity, a target lateral acceleration, a target lateral jerk and a weight coefficient of a quintic polynomial;

[0082] It should be noted that the target lateral velocity refers to the target value of the lateral velocity function that varies with time and is calculated based on the fifth-order polynomial expression. It is used to measure and control the lateral velocity characteristics of the vehicle, not just the speed at the end point. The target lateral acceleration represents the lateral acceleration information generated by the fifth-order polynomial, that is, the acceleration characteristics of the vehicle that vary with time on the entire correction trajectory. The target lateral acceleration controls the degree of acceleration or deceleration of the vehicle during the correction process. The target lateral acceleration will be used for optimization to meet the requirement of smooth acceleration changes throughout the trajectory. The target lateral jerk refers to the jerk information generated by the fifth-order polynomial, that is, the rate of change of acceleration. Jerk is used to measure the rate of change of acceleration in the trajectory, thereby controlling the stability of the vehicle and avoiding sudden acceleration changes during the correction process. The target jerk is used for optimization to make the entire correction process smooth and avoid vehicle shaking. The weight coefficient is used to control the relative importance of the target lateral velocity, target lateral acceleration and target lateral jerk in the optimization process. By setting different weights, specific parameters can be optimized preferentially to meet the comfort or control requirements in practical applications.

[0083] Step S312, constructing an optimization objective function according to the target lateral velocity, the target lateral acceleration, the target lateral jerk and the weight coefficient;

[0084] It can be understood that the parameters obtained in step S311, namely the target lateral velocity, the target lateral acceleration, the target lateral jerk and the weight coefficient, are used to construct an optimization objective function. The optimization objective function is as follows:

[0085]

[0086] Where, represents the lateral displacement of the vehicle that changes with time during trajectory generation, that is, the target lateral displacement, represents the target lateral acceleration, represents the target lateral acceleration, and w dis 、w acc and wjerk They represent the weight coefficients of target lateral velocity, target lateral acceleration and target lateral jerk respectively, and T is the total duration of trajectory planning.

[0087] Step S32, constraining the quintic polynomial according to the optimization objective function;

[0088] It can be understood that the optimization objective function constructed in step S31 is applied to the coefficients of the quintic polynomial to solve the problem, so that the polynomial finally generated can meet the optimization conditions in terms of the lateral displacement, acceleration and jerk of the trajectory. The constraint process mainly sets constraints for the quintic polynomial by optimizing the objective function, so that the target coefficients of the polynomial minimize the value of the optimization objective function while satisfying the boundary conditions. The constraint associates the coefficients of the quintic polynomial with the optimization conditions to ensure that the generated trajectory meets the smoothing and control requirements.

[0089] In a feasible implementation, step S32 may include steps S321 to S322:

[0090] Step S321, obtaining constraint conditions according to the optimization objective function;

[0091] It can be understood that extracting constraint conditions means extracting constraint conditions for trajectory generation from the optimization objective function. These constraint conditions include displacement, velocity, acceleration and jerk restrictions on the quintic polynomial, which are used to ensure that the trajectory meets the control requirements during the deviation correction process.

[0092] Specifically, the constraints may include the following aspects: Lateral displacement constraint means limiting the maximum lateral offset of the trajectory generated by the quintic polynomial to ensure that the trajectory meets the vehicle's offset control requirements. Lateral velocity constraint means controlling the lateral velocity change of the vehicle during the correction process to ensure that the vehicle does not suddenly speed up or slow down when moving laterally. Lateral acceleration constraint means setting the lateral acceleration of the vehicle so that it changes smoothly on the trajectory to avoid drastic lateral acceleration of the vehicle. Lateral jerk constraint means controlling the jerk of the trajectory to avoid sudden changes in acceleration on the trajectory and improve the smoothness of the trajectory.

[0093] Step S322, obtaining constraint conditions according to the optimization objective function, and applying the constraint conditions to a quintic polynomial.

[0094] It is understandable that after the constraints are introduced, the solution of the quintic polynomial becomes a constrained optimization problem. By combining boundary conditions, such as the displacement, velocity, acceleration requirements of the starting and end points and these constraints, the target coefficients of the quintic polynomial can be solved. By applying these constraints to the quintic polynomial, it can be ensured that the generated trajectory not only meets the current driving needs of the vehicle, but also meets the preset optimization goals. Specifically, the application of these constraints enables the vehicle to smoothly return to the lane during the correction process, while avoiding sharp acceleration, deceleration or shaking, thereby improving driving safety and riding comfort.

[0095] Step S33, converting the optimization objective function into a quadratic programming problem, and solving the quadratic programming problem to obtain the target coefficients of the quintic polynomial.

[0096] It should be noted that quadratic programming (QP) is an optimization method used to solve optimization problems with quadratic objective functions and linear constraints. In this embodiment, by converting the optimization objective function into a quadratic programming problem, the objective coefficients of the polynomial can be efficiently solved.

[0097] It can be understood that the formula for the quadratic programming problem is as follows:

[0098]

[0099] In the formula, x represents the optimization variable vector, that is, the variable to be solved; H represents the Hessian matrix, which describes the quadratic coefficient matrix of the objective function; f represents the linear term vector, which describes the linear coefficient of the objective function; x T represents the transpose of vector x; represents the quadratic term of the objective function. By minimizing this term, the acceleration and smoothness of the trajectory can be optimized; f T x represents the linear term of the objective function, which is related to the smoothness of the displacement and velocity of the trajectory. st is the abbreviation of "subject to", indicating that the following is a constraint condition; A eq x=b eq Represents a linear equality constraint, where: A eq b represents the coefficient matrix of the equality constraints, describing the constraints of the quintic polynomial on boundary conditions such as initial position, velocity and acceleration; b eq A constant vector representing the equality constraints, which represents the specific values ​​of the boundary conditions. Where f = (0; 0; 0; 0; 0; 0), x = (c0; c1; c2; c3; c4; c5).

[0100] In a feasible implementation manner, step S33 may include steps S331 to S333:

[0101] Step S331, constructing a matrix for the quadratic programming problem to obtain a Hessian matrix;

[0102] It should be noted that the Hessian Matrix is ​​a square matrix that represents the second-order derivative (i.e., Hessian) of the quadratic optimization objective function. In the quadratic programming problem, the Hessian Matrix contains quadratic term coefficients, reflecting the second-order influence of the optimization objective function on each variable.

[0103] It can be understood that the matrix of the quadratic programming problem can be constructed based on the quintic polynomial. The quintic polynomial is as follows:

[0104] y(t)=c0+c1t+c2t 2 +c3t 3 +c4t 4 +c5t 5 (Formula 3)

[0105] In the formula, t is time, c is i (i=0,1…5) are polynomial coefficients.

[0106] From formula 3, we can get the matrix of the quadratic programming problem, which is formula 4:

[0107]

[0108] According to the optimization objective function of formula 1 and formula 4, the Hessian matrix can be obtained. The Hessian matrix of the lateral velocity is as follows:

[0109]

[0110] According to the derivation method of equations 3 to 5, the Hessian matrix of the lateral acceleration and lateral acceleration jerk value can be obtained:

[0111] The Hessian matrix of the lateral acceleration is as follows:

[0112]

[0113] The Hessian matrix of the lateral acceleration is as follows:

[0114]

[0115] From equations 5 to 7, the final Hessian matrix can be obtained as follows:

[0116] H=H dis × dis +H acc × acc +H jerk × jerk (Formula 8)

[0117] Step S332, the Hessian matrix and the optimization objective function constraint condition are combined to obtain the objective constraint condition;

[0118] It should be noted that the target constraints are generated based on the constraints of the quadratic optimization objective function, the Hessian matrix, and the gradient vector when constructing the quadratic programming problem. They usually include boundary conditions (such as initial and terminal lateral positions, velocities, and accelerations) and trajectory smoothness requirements.

[0119] It can be understood that according to the actual functional requirements, the end point is tangent to the lane, and according to the constraint conditions, the following formula 9 can be listed:

[0120]

[0121] In the formula, t0 represents the initial time, t1 represents the end time of trajectory generation, d1 represents the lateral displacement, that is, the position of the vehicle at the end of the correction, and v0 represents the speed at the beginning of the correction. Formula 9 can be transformed into the constraint equation in Formula 2. Due to the initial point time, the target constraint condition is as follows: Formula 10:

[0122]

[0123] Step S333, obtaining the target coefficients of the quintic polynomial according to the target constraint condition and the Hessian matrix.

[0124] It is understandable that H, A eq , b eq , and f defined in equation 2, that is, the linear term vector, are substituted into the QP function to solve the corresponding polynomial coefficients. The relationship between lateral displacement and time is a quintic polynomial with 6 unknown polynomial coefficients. Initially, there is no lateral acceleration, only five of the conditions, so the relationship between lateral displacement and time can be solved with one condition. Then the optimization function is equivalent to solving this condition, and this condition can satisfy the constraints of lateral distance, lateral acceleration, and lateral acceleration jerk, and the vehicle can be corrected.

[0125] Step S40, generating a deviation correction trajectory according to the quintic polynomial and the target coefficient.

[0126] It should be noted that the correction trajectory describes the lateral position of the vehicle during the entire correction process and the displacement curve that changes over time, ensuring that the vehicle gradually and smoothly approaches the center of the lane. Through the generated trajectory, the vehicle control system can guide the vehicle back to the center of the lane along this path, thereby realizing the correction function.

[0127] It can be understood that in the previous step, the target coefficients of the quintic polynomial have been determined, and when the vehicle deviates from the position, such as Figure 2When the deviation correction starts at point S1, the lateral displacement over time is calculated according to the target coefficient of the determined quintic polynomial based on time t, thereby obtaining the lateral position of the vehicle at each moment. As time goes by, the vehicle gradually moves closer to the center of the lane along this generated trajectory, and finally completes the deviation correction at point S2.

[0128] This embodiment provides a lane correction trajectory generation method, which solves the technical problems of trajectory smoothness and control accuracy of the vehicle during the lane correction process by constructing a quintic polynomial and combining it with the technical means of optimizing the objective function, thereby achieving the beneficial effect of improving the safety, comfort and control efficiency of the lane correction trajectory.

[0129] 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-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. Figure 3 , step S20 of the lane deviation correction trajectory generation method includes steps S21 to S24:

[0130] Step S21, constructing a lateral displacement time function according to the polynomial coefficients and the current time;

[0131] It should be noted that the lateral displacement time function describes the relationship between the displacement of the vehicle in the lateral direction and time. Through this function, the lateral displacement of the vehicle in the entire deviation correction process can be determined. The lateral displacement time function is shown in the above formula 3.

[0132] Step S22, constructing a longitudinal displacement time function according to the initial lateral velocity and the current time;

[0133] It should be noted that the longitudinal displacement time function describes the change of the vehicle's displacement along the lane direction over time. It combines the vehicle's current longitudinal speed and position to ensure that the vehicle does not deviate from the smooth longitudinal movement requirements during the correction process. Since the longitudinal speed changes slightly, the initial vehicle speed is used as the longitudinal speed of the adjustment process. The longitudinal displacement time function is as follows:

[0134] x(t)=v0×t (Equation 11)

[0135] Where v0 is the initial lateral velocity and t is the time.

[0136] Step S23, obtaining a target lateral velocity, a target lateral acceleration and a lateral jerk according to the lateral displacement time function;

[0137] It can be understood that the target lateral velocity is obtained by taking the first-order derivative of the lateral displacement time function to obtain the target value of the lateral velocity function of the vehicle on the entire deviation correction trajectory. The target lateral velocity is calculated as follows:

[0138] y(t) ′ =c1+2c2t+3c3t 2 +4c4t 3 +5c5t 4 (Formula 12)

[0139] In the formula, t is time, c is i (i=0,1…5) are polynomial coefficients.

[0140] The target lateral acceleration can be obtained by taking the second-order derivative of the lateral displacement time function to obtain the acceleration of the vehicle on the trajectory that changes with time. The target lateral acceleration is calculated as follows:

[0141] y(t) ″ =2c2+6c3t+12c4t 2 +20c5t 3 (Formula 13)

[0142] In the formula, t is time, c is i (i=0,1…5) are polynomial coefficients.

[0143] By taking the third-order derivative of the lateral displacement time function, the vehicle lateral acceleration (jerk) is obtained. The lateral jerk is calculated as follows:

[0144] y(t) ″′ =6c3+24c4t+60c5t 2 (Formula 14)

[0145] In the formula, t is time, c is i (i=0,1…5) are polynomial coefficients.

[0146] Step S24, constructing boundary conditions according to the initial lateral velocity, and constructing a quintic polynomial according to the boundary conditions.

[0147] It should be noted that the boundary conditions are used to limit the coefficients of the quintic polynomial so that the trajectory it generates meets the requirements of the initial and target states of the vehicle. The construction of boundary conditions includes but is not limited to initial lateral displacement, initial lateral velocity, target lateral displacement, target lateral velocity, and target lateral acceleration.

[0148] In a feasible implementation, step S24 may include steps S241 to S244:

[0149] Step S241, obtaining an initial lateral displacement, a target lateral displacement, a target lateral velocity, and a target lateral acceleration of the vehicle;

[0150] Step S242, constructing boundary conditions according to the initial lateral velocity, the initial lateral displacement, the target lateral displacement, the target lateral velocity, and the target lateral acceleration;

[0151] It can be understood that steps S241 to S242 represent building boundary conditions according to the parameters after acquiring the initial lateral displacement, the target lateral displacement, the target lateral velocity and the target lateral acceleration.

[0152] In a feasible implementation, step S242 may include steps S2421 to S2423:

[0153] Step S2421, constructing a starting condition according to the initial lateral displacement and the initial lateral velocity;

[0154] It should be noted that the starting condition ensures that the initial state of the trajectory generation is consistent with the actual offset and movement of the vehicle, providing an initial boundary for generating a smooth correction trajectory. Using the initial lateral displacement and initial lateral velocity, the starting condition of the vehicle at the beginning of the correction trajectory is constructed. The starting condition is as follows:

[0155]

[0156] In the formula, y(t0)=d0 means that the lateral displacement at the initial time t0 is d0, y(t0) ' =v0 means that the lateral velocity at the initial time t0 is v0.

[0157] Step S2422, constructing a termination condition according to the target lateral displacement, the target lateral velocity, and the target lateral acceleration;

[0158] It should be noted that the termination condition ensures that the terminal state of the trajectory generation meets the final desired position and state of the vehicle, so that the vehicle can stop smoothly when the correction is completed. The termination condition of the trajectory is constructed using the target lateral displacement, lateral velocity and lateral acceleration. The termination condition is as follows:

[0159]

[0160] In the formula, y(t1)=d1 means that the lateral displacement at the target time t1 is d1, y(t1) ′ =v1 means that the lateral velocity at the target time t1 is v1, and y(t1)″=a1 means that the lateral acceleration at the target time t1 is a1.

[0161] Step S2423, constructing boundary conditions according to the starting conditions and the ending conditions.

[0162] It can be understood that the combination of the starting condition and the ending condition can form a complete boundary condition. The boundary condition describes the starting and ending states of the vehicle during the correction process, covering parameters such as lateral displacement, velocity and acceleration.

[0163] Step S243, generating a target equation group according to the boundary conditions;

[0164] Step S244, solving the target coefficients of the quintic polynomial according to the target equation group.

[0165] It is understandable that in step S243 and step S244, boundary conditions are first set according to the state of the vehicle at the beginning and end of the deviation correction, and these conditions include the initial and target lateral positions, lateral speeds, lateral accelerations, etc. Step S243 uses these boundary conditions to construct a target set of equations, which describes the motion requirements of the quintic polynomial on the entire deviation correction trajectory. Then, in step S244, the target set of equations is solved to determine the specific coefficients of the quintic polynomial. These coefficients determine the shape of the generated trajectory, so that the vehicle can smoothly move from the initial position to the target position gradually during the deviation correction process, and reach the preset speed and acceleration requirements at the end, thereby achieving the smoothness of the trajectory and the accuracy of control.

[0166] This embodiment provides a lane correction trajectory generation method, which solves the accuracy and smoothness problems of trajectory generation in the lane correction process by constructing a lateral displacement time function and a longitudinal displacement time function and solving the fifth-order polynomial coefficients in combination with boundary conditions, thereby achieving the beneficial effects of improving vehicle correction efficiency, ensuring driving safety and enhancing ride comfort.

[0167] 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 correction trajectory generation method of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0168] This application also provides a lane correction trajectory generation device, please refer to Figure 4 , the lane deviation correction trajectory generating device comprises:

[0169] An acquisition module 10, for acquiring the longitudinal speed, current time and initial lateral speed of the vehicle when it is detected that the lane deviation correction function of the vehicle is activated;

[0170] A construction module 20, configured to construct a quintic polynomial according to the longitudinal velocity, the current time and the initial lateral velocity;

[0171] An obtaining module 30 is used to obtain the target coefficient of the quintic polynomial according to the quintic polynomial and the optimization target function;

[0172] The generating module 40 is used to generate a deviation correction trajectory according to the quintic polynomial and the target coefficient.

[0173] The lane correction trajectory generation device provided by the present application adopts the lane correction trajectory generation method in the above embodiment, which can solve the technical problem that the lane correction trajectory generation method lacks optimized control of lateral position, acceleration and jerk, and is difficult to achieve a smooth and accurate correction trajectory. Compared with the prior art, the beneficial effects of the lane correction trajectory generation device provided by the present application are the same as the beneficial effects of the lane correction trajectory generation method provided by the above embodiment, and the other technical features in the lane correction trajectory generation device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0174] In one embodiment, the obtaining module 30 is also used to construct an optimization objective function based on a quintic polynomial; constrain the quintic polynomial according to the optimization objective function; convert the optimization objective function into a quadratic programming problem, and solve the quadratic programming problem to obtain the target coefficient of the quintic polynomial.

[0175] In one embodiment, the obtaining module 30 is also used to obtain the target lateral velocity, target lateral acceleration, target lateral jerk and weight coefficient of the quintic polynomial; construct an optimization objective function based on the target lateral velocity, the target lateral acceleration, the target lateral jerk and the weight coefficient; the step of constraining the quintic polynomial according to the optimization objective function includes: obtaining constraint conditions according to the optimization objective function; obtaining constraint conditions according to the optimization objective function, and applying the constraint conditions to the quintic polynomial.

[0176] In one embodiment, the obtaining module 30 is also used to construct a matrix of a quadratic programming problem to obtain a Hessian matrix; the Hessian matrix and the optimization objective function constraints are combined to obtain target constraints; and the target coefficients of the quintic polynomial are obtained based on the target constraints and the Hessian matrix.

[0177] In one embodiment, the construction module 20 is further used to construct a lateral displacement time function based on the polynomial coefficients and the current time; to construct a longitudinal displacement time function based on the initial lateral velocity and the current time; to obtain a target lateral velocity, a target lateral acceleration and a lateral jerk based on the lateral displacement time function; to construct boundary conditions based on the initial lateral velocity, and to construct a quintic polynomial based on the boundary conditions.

[0178] In one embodiment, the construction module 20 is further used to obtain an initial lateral displacement, a target lateral displacement, a target lateral velocity and a target lateral acceleration of the vehicle; construct boundary conditions according to the initial lateral velocity, the initial lateral displacement, the target lateral displacement, the target lateral velocity and the target lateral acceleration; generate a target equation group according to the boundary conditions; and solve the target coefficients of a quintic polynomial according to the target equation group.

[0179] In one embodiment, the construction module 20 is further used to construct a starting condition based on the initial lateral displacement and the initial lateral velocity; to construct a termination condition based on the target lateral displacement, the target lateral velocity and the target lateral acceleration; and to construct a boundary condition based on the starting condition and the termination condition.

[0180] The present application provides a lane correction trajectory generation 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 so that the at least one processor can execute the lane correction trajectory generation method in the above-mentioned embodiment one.

[0181] Reference below Figure 5 , which shows a schematic diagram of the structure of a lane deviation correction trajectory generation device suitable for implementing the embodiment of the present application. The lane deviation correction trajectory generation 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), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 5 The lane correction trajectory generation device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0182] like Figure 5As shown, the lane deviation correction trajectory generation device may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the lane deviation correction trajectory generation device are also stored. The processing device 1001, ROM1002, and RAM1004 are connected to each other via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 1003 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 1009. The communication device 1009 can allow the lane correction trajectory generation device to communicate wirelessly or wired with other devices to exchange data. Although the figure shows a lane correction trajectory generation device with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have alternatively.

[0183] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a 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 through 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.

[0184] The lane correction trajectory generation device provided by the present application adopts the lane correction trajectory generation method in the above embodiment, which can solve the technical problem that the lane correction trajectory generation method lacks optimized control of lateral position, acceleration and jerk, and is difficult to achieve a smooth and accurate correction trajectory. Compared with the prior art, the beneficial effects of the lane correction trajectory generation device provided by the present application are the same as the beneficial effects of the lane correction trajectory generation method provided by the above embodiment, and the other technical features in the lane correction trajectory generation device are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0185] It should be understood that the various parts disclosed in this application can be implemented by 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.

[0186] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0187] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the lane correction trajectory generation method in the above-mentioned embodiment.

[0188] The computer-readable storage medium provided in the present 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 of the above. 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 of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination 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 of the above.

[0189] The computer-readable storage medium may be included in the lane deviation correction trajectory generation device; or may exist independently without being assembled into the lane deviation correction trajectory generation device.

[0190] The above-mentioned computer-readable storage medium carries one or more programs. When the above-mentioned one or more programs are executed by the lane correction trajectory generating device, the lane correction trajectory generating device: when detecting that the lane correction function of the vehicle is activated, obtains the longitudinal speed, current time and initial lateral speed of the vehicle; constructs a quintic polynomial according to the longitudinal speed, the current time and the initial lateral speed; obtains the target coefficient of the quintic polynomial according to the quintic polynomial and the optimization objective function; and generates a correction trajectory according to the quintic polynomial and the target coefficient.

[0191] 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 separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of 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., via the Internet using an Internet service provider).

[0192] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the 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 square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square 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 square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0193] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0194] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned lane correction trajectory generation method, and can solve the technical problem that the lane correction trajectory generation method lacks optimized control of lateral position, acceleration, and jerk, and is difficult to achieve a smooth and accurate correction trajectory. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the lane correction trajectory generation method provided in the above-mentioned embodiment, and will not be repeated here.

[0195] The present application also provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the lane correction trajectory generation method as described above.

[0196] The computer program product provided by the present application can solve the technical problem that the lane deviation correction trajectory generation method lacks optimized control of lateral position, acceleration and jerk, and is difficult to achieve a smooth and accurate deviation correction trajectory. Compared with the prior art, the beneficial effects of the computer program product provided by the present application are the same as the beneficial effects of the lane deviation correction trajectory generation method provided by the above embodiment, and will not be repeated here.

[0197] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A lane correction trajectory generation method, characterized in that: The method comprises: When it is detected that the lane deviation correction function of the vehicle is activated, obtaining the longitudinal speed, current time and initial lateral speed of the vehicle; constructing a fifth-order polynomial according to the longitudinal velocity, the current time, and the initial lateral velocity; According to the quintic polynomial and the optimization objective function, obtaining the target coefficient of the quintic polynomial; A deviation correction trajectory is generated according to the quintic polynomial and the target coefficient.

2. The method according to claim 1, characterized in that The step of obtaining the target coefficient of the quintic polynomial according to the quintic polynomial and the optimization objective function comprises: Construct the optimization objective function based on the quintic polynomial; constraining the quintic polynomial according to the optimization objective function; The optimization objective function is converted into a quadratic programming problem, and the quadratic programming problem is solved to obtain the objective coefficients of the quintic polynomial.

3. The method according to claim 2, characterized in that The step of constructing an optimization objective function according to a quintic polynomial comprises: Obtaining a target lateral velocity, a target lateral acceleration, a target lateral jerk, and a weight coefficient of a quintic polynomial; constructing an optimization objective function according to the target lateral velocity, the target lateral acceleration, the target lateral jerk, and the weight coefficient; The step of constraining the quintic polynomial according to the optimization objective function comprises: Obtaining constraint conditions according to the optimization objective function; A constraint condition is obtained according to the optimization objective function, and the constraint condition is applied to a quintic polynomial.

4. The method according to claim 2, characterized in that The step of converting the optimization objective function into a quadratic programming problem and solving the quadratic programming problem to obtain the target coefficient of the quintic polynomial includes: Construct the matrix of the quadratic programming problem and obtain the Hessian matrix; The Hessian matrix and the optimization objective function constraint condition are combined to obtain the objective constraint condition; According to the target constraint condition and the Hessian matrix, the target coefficients of the quintic polynomial are obtained.

5. The method according to claim 1, characterized in that The step of constructing a quintic polynomial according to the longitudinal velocity, the current time and the initial lateral velocity comprises: Constructing a lateral displacement time function according to the polynomial coefficients and the current time; constructing a longitudinal displacement time function according to the initial lateral velocity and the current time; According to the lateral displacement time function, a target lateral velocity, a target lateral acceleration and a lateral jerk are obtained; A boundary condition is constructed according to the initial lateral velocity, and a quintic polynomial is constructed according to the boundary condition.

6. The method according to claim 5, characterized in that The step of constructing a boundary condition according to the initial lateral velocity and constructing a quintic polynomial according to the boundary condition comprises: Obtaining an initial lateral displacement, a target lateral displacement, a target lateral velocity, and a target lateral acceleration of the vehicle; constructing a boundary condition based on the initial lateral velocity, the initial lateral displacement, the target lateral displacement, the target lateral velocity, and the target lateral acceleration; generating a target set of equations according to the boundary conditions; The target coefficients of the quintic polynomial are solved according to the target equation group.

7. The method according to claim 6, characterized in that The step of constructing the boundary condition according to the initial lateral velocity, the initial lateral displacement, the target lateral displacement, the target lateral velocity and the target lateral acceleration comprises: constructing a starting condition based on the initial lateral displacement and the initial lateral velocity; Establishing a termination condition according to the target lateral displacement, the target lateral velocity, and the target lateral acceleration; The boundary conditions are constructed according to the starting conditions and the ending conditions.

8. A lane correction trajectory generation device, characterized in that: The device comprises: An acquisition module, for acquiring the longitudinal speed, current time and initial lateral speed of the vehicle when detecting that the lane deviation correction function of the vehicle is activated; A construction module, configured to construct a quintic polynomial according to the longitudinal velocity, the current time and the initial lateral velocity; An obtaining module, used for obtaining target coefficients of the quintic polynomial according to the quintic polynomial and an optimization target function; A generation module is used to generate a correction trajectory according to the quintic polynomial and the target coefficient.

9. A lane correction trajectory generation device, characterized in that: The device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the lane correction trajectory generation method according to any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the lane correction trajectory generation method according to any one of claims 1 to 7 are implemented.

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