Vehicle lateral control method and device thereof, storage medium and electronic equipment

Abstract

The application relates to a vehicle lateral control method and device, a storage medium and an electronic device, which comprises the following steps: selecting a trajectory point from a planned trajectory as a preview point according to a current minimum turning radius; determining a first front wheel turning angle required for the vehicle to move from a current vehicle position to the preview point according to the current minimum turning radius; determining a second front wheel turning angle required for the vehicle to move from the current vehicle position to the preview point according to a current vehicle heading angle and a vehicle heading angle of the preview point; determining a current front wheel turning angle control amount according to the first front wheel turning angle, the second front wheel turning angle, a last output front wheel turning angle control amount, a current vehicle front wheel turning angle and a turning angle correction coefficient, and judging whether the current front wheel turning angle control amount meets the requirements; if yes, outputting the current front wheel turning angle control amount; and if no, adjusting the turning angle correction coefficient until a current front wheel turning angle control amount meeting the requirements is obtained and outputted. The application can balance control accuracy and calculation power consumption in vehicle lateral control.

Description

Technical Field

[0001] The present application relates to the field of automobile technology, and in particular to a vehicle lateral control method and device, storage medium, and electronic device. Background Art

[0002] Intelligence is a key development trend in the automotive industry, and a key manifestation of this intelligence is autonomous driving. Autonomous driving involves both lateral and longitudinal control. Lateral control is crucial for trajectory tracking and is categorized into two types: dynamic and kinematic models, depending on the vehicle modeling approach.

[0003] The main algorithms based on dynamic models include the MPC algorithm and the LQR algorithm. The MPC algorithm and the LQR algorithm can simultaneously consider position and orientation errors. Most of the LQR and MPC algorithms require optimization algorithms to find the optimal solution in the corresponding time domain while taking into account position and heading tracking. However, the iterative solution of the design state matrix requires more computing power.

[0004] The main algorithms based on kinematic models are the PurePursuit algorithm and the Stanley algorithm. The PurePursuit algorithm is a simple geometric tracking algorithm that consumes almost no computing power, but can only follow waypoints and does not follow heading, and its applicable scenarios are limited. The Stanley algorithm is based on the error of the front wheel for control and is highly dependent on the control gain. The control gain varies in different scenarios and is difficult to calibrate. Therefore, the PurePursuit algorithm and the Stanley algorithm have low computing power consumption, but the control accuracy is not as good as the MPC algorithm and the LQR algorithm.

[0005] Therefore, there is an urgent need to develop a technical solution that can balance control accuracy and computing power overhead to achieve lateral control of the vehicle. Summary of the Invention

[0006] The purpose of this application is to propose a vehicle lateral control method and its device, storage medium, and electronic device, which can take into account both control accuracy and computing power overhead during the vehicle lateral control process.

[0007] To achieve the above objectives, an embodiment of the present application provides a vehicle lateral control method, the method comprising:

[0008] Selecting a trajectory point as a preview point from a planned trajectory according to the current minimum turning radius; the planned trajectory includes a plurality of trajectory points and a position and vehicle heading angle corresponding to each trajectory point;

[0009] Determining a first front wheel turning angle required for the vehicle to move from a current vehicle position to the preview point according to the current minimum turning radius;

[0010] Determining a second front wheel turning angle required for the vehicle to move from the current vehicle position to the preview point based on the current vehicle heading angle and the vehicle heading angle of the preview point;

[0011] The current front wheel angle control amount is determined based on the first front wheel angle, the second front wheel angle, the front wheel angle control amount output last time, the current vehicle front wheel angle, and the angle correction coefficient. If the current front wheel angle control amount meets the preset lateral deviation control requirement, the current front wheel angle control amount is output.

[0012] In some embodiments, the method further comprises:

[0013] If the current front wheel steering angle control amount does not meet the preset lateral deviation control requirement, the steering angle correction coefficient is adjusted and the current front wheel steering angle control amount is re-determined until the current front wheel steering angle control amount that meets the preset lateral deviation control requirement is obtained and output.

[0014] In some embodiments, determining the current front wheel angle control amount based on the first front wheel angle, the second front wheel angle, the last output front wheel angle control amount, the current vehicle front wheel angle, and the angle correction coefficient specifically includes:

[0015] The first front wheel angle, the second front wheel angle, the front wheel angle control value output last time, and the current vehicle front wheel angle are weightedly summed, and the weighted summation result is corrected according to the angle correction coefficient to obtain the current front wheel angle control value.

[0016] In some embodiments, determining the current front wheel angle control amount based on the first front wheel angle, the second front wheel angle, the last output front wheel angle control amount, the current vehicle front wheel angle, and the angle correction coefficient specifically further includes:

[0017] The weight coefficients of the first front wheel steering angle and the second front wheel steering angle are determined based on the lateral deviation between the current vehicle position and the preview point; wherein the lateral deviation is positively correlated with the weight coefficient of the first front wheel steering angle, and the lateral deviation is negatively correlated with the weight coefficient of the second front wheel steering angle.

[0018] In some embodiments, whether the current front wheel steering angle control value meets the preset lateral deviation control requirement is determined in the following manner:

[0019] Assuming that the current front wheel steering angle control amount is valid, the predicted trajectory of the vehicle is predicted based on the current front wheel steering angle control amount, and whether an unexpected overshoot occurs is determined according to the lateral deviation between the predicted trajectory and the planned trajectory. If not, the current front wheel steering angle control amount meets the preset lateral deviation control requirement. If so, the current front wheel steering angle control amount does not meet the preset lateral deviation control requirement.

[0020] In some embodiments, predicting a predicted trajectory of the vehicle based on the current front wheel steering angle control amount, and determining whether an unexpected overshoot occurs based on a lateral deviation between the predicted trajectory and the planned trajectory, specifically includes:

[0021] The predicted trajectory includes a plurality of predicted points;

[0022] If the lateral deviations between the plurality of prediction points and the plurality of trajectory points corresponding thereto do not exceed the expected overshoot, then the current front wheel steering angle control amount meets the preset lateral deviation control requirement;

[0023] If a lateral deviation between at least one of the plurality of prediction points and a corresponding trajectory point exceeds an expected overshoot, the current front wheel steering angle control amount does not meet a preset lateral deviation control requirement.

[0024] In some embodiments, the first predicted point of the predicted trajectory is obtained by predicting the next arrival position and vehicle heading angle of the vehicle based on the current front wheel steering angle control value, the current position of the vehicle, and the position of the preview point, and the position is the first predicted point of the predicted trajectory;

[0025] All predicted points except the first predicted point in the predicted trajectory are obtained in the following manner: obtaining the front wheel steering angle control value corresponding to the current predicted point and the trajectory point corresponding to the current predicted point in the planned trajectory, and predicting the next arrival position and vehicle heading angle of the vehicle based on the front wheel steering angle control value corresponding to the current predicted point, the position of the current predicted point, and the position of the trajectory point corresponding to the current predicted point, with the position point being the next predicted point in the predicted trajectory;

[0026] The front wheel steering angle control amount corresponding to the current prediction point is obtained according to the following method: determining the third front wheel steering angle required for the vehicle to move from the current prediction point to the trajectory point corresponding to the current prediction point according to the current minimum turning radius, determining the fourth front wheel steering angle required for the vehicle to move from the current prediction point to the trajectory point corresponding to the current prediction point according to the vehicle heading angle of the current prediction point and the vehicle heading angle of the trajectory point corresponding to the current prediction point, and determining the front wheel steering angle control amount corresponding to the current prediction point according to the third front wheel steering angle and the fourth front wheel steering angle.

[0027] In some embodiments, determining the front wheel steering angle control amount corresponding to the current prediction point based on the third front wheel steering angle and the fourth front wheel steering angle specifically includes:

[0028] The third front wheel steering angle and the fourth front wheel steering angle are weightedly summed, and the weighted summation result is corrected according to the steering angle correction coefficient to obtain the front wheel steering angle control amount corresponding to the current prediction point.

[0029] In some embodiments, determining the front wheel steering angle control amount corresponding to the current prediction point based on the third front wheel steering angle and the fourth front wheel steering angle specifically further includes:

[0030] Obtain a lateral deviation between a current prediction point and a trajectory point corresponding to the current prediction point, and determine weight coefficients of the third and fourth front wheel turning angles based on the lateral deviation; wherein the lateral deviation is positively correlated with the weight coefficient of the third front wheel turning angle, and the lateral deviation is negatively correlated with the weight coefficient of the fourth front wheel turning angle.

[0031] In some embodiments, selecting a trajectory point from the planned trajectory as a preview point based on the current minimum turning radius specifically includes:

[0032] Obtaining a current vehicle speed, looking up a table to obtain a maximum front wheel turning angle corresponding to the current vehicle speed, and obtaining a minimum turning radius based on the maximum front wheel turning angle;

[0033] With the minimum turning radius as a constraint condition, a trajectory point closest to the current vehicle position among the multiple trajectory points is selected as a preview point.

[0034] In some embodiments, the method further comprises:

[0035] A steering wheel angle is obtained based on the current front wheel angle control amount that meets the preset lateral deviation control requirements, and the steering wheel angle is low-pass filtered and output to a downstream module; the downstream module is used to control the lateral movement of the vehicle based on the steering wheel angle.

[0036] An embodiment of the present application further provides a vehicle lateral control device, comprising a module for executing the vehicle lateral control method as described above.

[0037] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the vehicle lateral control method as described above is implemented.

[0038] An embodiment of the present application also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the vehicle lateral control method as described above when executing the computer program.

[0039] The embodiment of the present application provides a vehicle lateral control method and device, a storage medium and an electronic device. A pre-look point is determined according to a current minimum turning radius and a plurality of track points provided by a planning track, and a first front wheel steering angle required for a vehicle to move from a current vehicle position to the pre-look point is determined according to the current minimum turning radius. The first front wheel steering angle can effectively make the vehicle close to the pre-look point as soon as possible, but the first front wheel steering angle is prone to overshoot caused by a short pre-look distance. Therefore, a second front wheel steering angle required for the vehicle to move from the current vehicle position to the pre-look point is determined according to a current vehicle heading angle and a vehicle heading angle of the pre-look point. A current front wheel steering angle control quantity is determined according to the first front wheel steering angle, the second front wheel steering angle, a last output front wheel steering angle control quantity, a current vehicle front wheel steering angle and a steering angle correction coefficient. The second front wheel steering angle can simultaneously consider tracking of the vehicle heading and ensure that the vehicle can follow a road point according to a heading of the planning track, and can effectively alleviate the overshoot caused by the short pre-look distance. Finally, it is determined whether the current front wheel steering angle control quantity meets a preset lateral deviation control requirement. If yes, the current front wheel steering angle control quantity is output. Compared with an iterative method of an MPC algorithm and an LQR algorithm, the embodiment of the present application only performs numerical judgment, can greatly reduce the occupation of computing power, balances the computing power and improves the control effect, realizes the prediction function, reduces the computing power cost caused by the linear solving algorithm, finally achieves an ideal control effect, reduces the computing power cost, and greatly reduces the computing power requirement of the controller, which is more suitable for mass production. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any inventive labor.

[0041] Figure 1 A flowchart of a vehicle lateral control method in an embodiment of the present application.

[0042] Figure 2 A vehicle motion model schematic diagram in an embodiment of the present application.

[0043] Figure 3 A schematic diagram of a planning track and a prediction track in an embodiment of the present application.

[0044] Figure 4 A schematic diagram of a front wheel steering angle and a steering wheel steering angle corresponding relationship in an embodiment of the present application. DETAILED DESCRIPTION

[0045] The detailed description of the accompanying drawings is intended to serve as an illustration of the current embodiment of the present application and is not intended to represent the only form in which the present application can be implemented. It should be understood that the same or equivalent functions can be accomplished by different embodiments intended to be included in the spirit and scope of the present application.

[0046] An embodiment of the present application provides a vehicle lateral control method, see Figure 1 The method of this embodiment includes the following steps:

[0047] Step S10: selecting a trajectory point from the planned trajectory as a preview point according to the current minimum turning radius; the planned trajectory includes multiple trajectory points and the position and vehicle heading angle corresponding to each trajectory point.

[0048] Specifically, the planned trajectory in step S10 refers to a predicted trajectory from the starting point to the end point or key points along the way, calculated by the vehicle according to a certain path planning algorithm. The planned trajectory can be obtained in a variety of ways, such as planning based on map information, sensor data, and prior knowledge. The planning of the planned trajectory is implemented by the vehicle's planning module. The planned trajectory includes multiple discrete trajectory points, which the vehicle needs to track during driving to ensure that the vehicle can travel along the planned trajectory; the preview point is a trajectory point in the planned trajectory that is closest to the vehicle and can be reached by the vehicle in the current state; the vehicle mentioned in this embodiment refers to this vehicle.

[0049] Step S20: determining a first front wheel turning angle required for the vehicle to move from the current vehicle position to the preview point according to the current minimum turning radius.

[0050] Specifically, if Figure 2 As shown, ignoring the Ackerman angle, using a single-vehicle model, let the vehicle's wheelbase be L, the front wheel angle be δ, O be the starting point, the vehicle's speed at the starting point be v0, R be the turning radius, O' be a moment d t The position of the rear vehicle, where t Assuming that the vehicle speed remains unchanged and the vehicle moves in the direction of the original speed, the following geometric relationship exists:

[0051] l d =v0d t (1)

[0052] sinα=l d / 2R (2)

[0053] tanδ=L / R (3)

[0054] x O′ =l d cosα (4)

[0055] y O′ =l d sinα (5)

[0056] ψ O′ =2α (6)

[0057] In the above formula, l d is the Euclidean distance from the starting point to the preview point, α is the angle between the vehicle's current heading and the line connecting the vehicle's current position and the preview point, and solving the above equations, we can get the vehicle's posture (x o′→o ,y o′→o ,ψ o′→o ):

[0058]

[0059]

[0060]

[0061] In a shorter time v0d t With l d0 Can be regarded as equal, based on the above formula, the first front wheel turning angle δ can be derived e_lat0 for:

[0062]

[0063] The Euclidean distance l between the current vehicle position and the preview point can be calculated according to the current vehicle position and the position of the preview point. d0 According to formula (2), we can get: sinα=l d0 / 2R, further, the vehicle wheelbase is a known parameter, therefore, according to the Euclidean distance l d0 Formula (10) can be used to calculate the first front wheel turning angle δ e_lat0 .

[0064] It should be noted that in this embodiment, the first front wheel turning angle required for the vehicle to move from the current vehicle position to the preview point is determined based on the current minimum turning radius. Controlling the lateral movement of the vehicle based on the first front wheel turning angle can effectively make the vehicle approach the preview point as quickly as possible.

[0065] Step S30 , determining a second front wheel turning angle required for the vehicle to move from the current vehicle position to the preview point according to the current vehicle heading angle and the vehicle heading angle of the preview point.

[0066] Specifically, if the first front wheel steering angle is obtained in step S20 alone to control the lateral movement of the vehicle, the vehicle heading often does not match the planned direction of the trajectory point. Therefore, it is necessary to consider the heading correction simultaneously, that is, in step S30, first calculate the heading angle deviation value Δ of the current vehicle heading angle and the vehicle heading angle of the preview point. ψ0 , further, the second front wheel turning angle δ can be calculated according to the following formula (11): e_head0 ;

[0067]

[0068] Step S40, determining the current front wheel angle control amount based on the first front wheel angle, the second front wheel angle, the front wheel angle control amount output last time, the current vehicle front wheel angle, and the angle correction coefficient; if the current front wheel angle control amount meets the preset lateral deviation control requirement, output the current front wheel angle control amount.

[0069] Specifically, in step S40, a front wheel angle control quantity is obtained based on the first front wheel angle, the second front wheel angle, the front wheel angle control quantity output last time, and the current vehicle front wheel angle, and the front wheel angle control quantity is corrected according to the angle correction coefficient to obtain the current front wheel angle control quantity. If the current front wheel angle control quantity meets the preset lateral deviation control requirement, that is, no unexpected overshoot occurs, the current front wheel angle control quantity is directly output to the downstream module for controlling the lateral movement of the vehicle.

[0070] The method of the embodiment determines a preview point according to the current minimum turning radius and a plurality of trajectory points provided by the planned trajectory, and determines a first front wheel steering angle required for the vehicle to move from the current vehicle position to the preview point according to the current minimum turning radius, which can effectively make the vehicle approach the preview point as soon as possible, but the first front wheel steering angle is prone to overshoot caused by a short preview distance. Therefore, the method of the embodiment further determines a second front wheel steering angle required for the vehicle to move from the current vehicle position to the preview point according to the current vehicle heading angle and the vehicle heading angle of the preview point, determines a current front wheel steering angle control amount according to the first front wheel steering angle, the second front wheel steering angle, a last output front wheel steering angle control amount, a current vehicle front wheel steering angle and a steering angle correction coefficient, the second front wheel steering angle can take into account the tracking of the vehicle heading at the same time, ensure that the vehicle can follow the waypoints according to the heading of the planned trajectory, and effectively alleviate the overshoot caused by the short preview distance. Finally, it is judged whether the current front wheel steering angle control amount meets the preset lateral deviation control requirement. If yes, the current front wheel steering angle control amount is output. If not, the steering angle correction coefficient is adjusted and the current front wheel steering angle control amount is determined again until the current front wheel steering angle control amount meeting the preset lateral deviation control requirement is obtained and output. Compared with the MPC algorithm and the LQR algorithm which must use an iterative method to optimize and solve the state matrix, the method of the embodiment only performs numerical judgment, which can greatly reduce the occupation of computing power. The method of the embodiment balances the computing power and improves the control effect, realizes the prediction function, reduces the computing power expenditure caused by the linear solving algorithm, and finally achieves an ideal control effect. Reducing the computing power expenditure greatly reduces the computing power requirement of the controller and is more suitable for mass production.

[0071] In some embodiments, the step S40 further comprises:

[0072] If the current front wheel steering angle control amount does not meet the preset lateral deviation control requirement, the steering angle correction coefficient is adjusted and the current front wheel steering angle control amount is determined again until the current front wheel steering angle control amount meeting the preset lateral deviation control requirement is obtained and output.

[0073] Specifically, if the current front wheel steering angle control amount obtained in step S40 does not meet the preset lateral deviation control requirement, that is, an unexpected overshoot occurs, the steering angle correction coefficient is adjusted, and the one front wheel steering angle control amount is corrected to obtain the current front wheel steering angle control amount, until a current front wheel steering angle control amount meeting the preset lateral deviation control requirement is obtained and output to a downstream module for controlling the lateral motion of the vehicle.

[0074] In some embodiments, determining the current front wheel angle control amount according to the first front wheel angle, the second front wheel angle, the last output front wheel angle control amount, the current vehicle front wheel angle, and the angle correction coefficient in step S40 specifically includes:

[0075] The first front wheel steering angle, the second front wheel steering angle, the front wheel steering angle control value outputted last time, and the current vehicle front wheel steering angle are weightedly summed, and the weighted summation result is corrected according to the steering angle correction coefficient to obtain the current front wheel steering angle control value, as shown in the following formula (12);

[0076] δ0=k fb (W lat0 ·δ elat0 +W ead0 ·δ eead0 +W istory ·δ istpry +W act ·δ act ) (12)

[0077] In formula (12), k fb is the steering angle correction coefficient, δ0 is the current front wheel steering angle control value, δ elat0 is the first front wheel turning angle, δ eead0 is the second front wheel turning angle, δ istory is the front wheel steering angle control value output last time, δ act is the current vehicle front wheel angle, W lat0 is the weight coefficient of the first front wheel turning angle, W ead0 is the weight coefficient of the second front wheel turning angle, W istory is the weight coefficient of the front wheel steering angle control value output last time, W act is the weight coefficient of the current vehicle's front wheel angle.

[0078] In some embodiments, determining the current front wheel angle control amount according to the first front wheel angle, the second front wheel angle, the last output front wheel angle control amount, the current vehicle front wheel angle, and the angle correction coefficient in step S40 specifically further includes:

[0079] The weight coefficients of the first front wheel steering angle and the second front wheel steering angle are determined based on the lateral deviation between the current vehicle position and the preview point; wherein the lateral deviation is positively correlated with the weight coefficient of the first front wheel steering angle, and the lateral deviation is negatively correlated with the weight coefficient of the second front wheel steering angle.

[0080] Specifically, W lat0 is a lateral deviation e lat0 The function can be expressed as W lat0 =f1(e lat0, the greater the lateral error e, the greater the coefficient W, and vice versa. head0 and e lat0 are positively correlated.

[0081] W head0 is also a function of the lateral error e lat0 , which can be expressed as W head0 = f2(e lat0 ), but the trend is the opposite, that is, the greater the lateral error e, the smaller the coefficient W, and vice versa. head0 and e lat0 are negatively correlated.

[0082] In some embodiments, whether the current front wheel steering angle control quantity meets the preset lateral deviation control requirement is determined according to the following manner:

[0083] Assuming that the current front wheel steering angle control quantity is valid, a predicted trajectory of the vehicle is predicted based on the current front wheel steering angle control quantity, and whether an unexpected overshoot amount ε k occurs is determined according to the lateral deviation between the predicted trajectory and the planned trajectory, if not, the current front wheel steering angle control quantity meets the preset lateral deviation control requirement, and if yes, the current front wheel steering angle control quantity does not meet the preset lateral deviation control requirement.

[0084] Specifically, assuming that the current front wheel steering angle control quantity is valid, the future trajectory of the vehicle under the control of the current front wheel steering angle control quantity can be predicted according to the current state of the vehicle, and the trajectory points corresponding to the predicted trajectory and the planned trajectory, Figure 3 two trajectories are shown, Figure 3 the left trajectory is the planned trajectory (solid line) output by the vehicle planning module, Figure 3 and the right trajectory is the predicted trajectory (dashed line), which has 9 predicted points, i.e., the k+1~k+9 points on the predicted trajectory, the kth point on the predicted trajectory is the point where the current position of the vehicle is located, the planned trajectory also has 9 trajectory points, i.e., the k+1~k+9 points on the planned trajectory, and the planned trajectory also has a preview point, the k+1~k+9 points on the predicted trajectory and the k+1~k+9 points on the planned trajectory have a one-to-one correspondence; in this embodiment, the lateral deviation between the predicted trajectory and the planned trajectory refers to the lateral deviation between two points, i.e., the lateral deviation between the predicted point on the predicted trajectory and the corresponding trajectory point on the planned trajectory; the unexpected overshoot amount ε k is the maximum deviation reached by the control system in the actual operation during the unexpected overshoot process, and the overshoot amount ε k is usually expressed in percentage or absolute value, which reflects the degree of oscillation generated in the system response process; wherein ε kIt is related to the step size. The smaller the step size, the smaller ε k The smaller the step size, the larger the step size. The step size refers to the number of points that need to be predicted.

[0085] In some embodiments, step S40 predicts a predicted trajectory of the vehicle based on the current front wheel steering angle control amount, and determines whether an unexpected overshoot occurs based on a lateral deviation between the predicted trajectory and the planned trajectory, specifically including:

[0086] The predicted trajectory includes multiple predicted points; for example Figure 3 As shown, the predicted trajectory includes 9 points;

[0087] If the lateral deviations between the multiple predicted points and the corresponding multiple trajectory points do not exceed the expected overshoot, the current front wheel steering angle control amount satisfies the preset lateral deviation control requirement, and the current front wheel steering angle control amount is output to a downstream module for controlling the lateral movement of the vehicle;

[0088] If the lateral deviation between at least one of the multiple prediction points and a corresponding trajectory point exceeds the expected overshoot, the current front wheel steering angle control amount does not meet the preset lateral deviation control requirement; therefore, in the actual control process, each time a prediction point is obtained, it is judged whether the lateral deviation between the prediction point and a corresponding trajectory point exceeds the expected overshoot. If so, the steering angle correction coefficient is adjusted, and the front wheel steering angle control amount is re-corrected to obtain the current front wheel steering angle control amount, until a current front wheel steering angle control amount that can meet the preset lateral deviation control requirement is obtained, and is output to the downstream module for controlling the lateral movement of the vehicle. If not, the next prediction point is predicted, and the lateral deviation between the next prediction point and a corresponding trajectory point is judged to exceed the expected overshoot, until the last prediction point.

[0089] In some embodiments, the first predicted point of the predicted trajectory is obtained according to the following method:

[0090] Predicting the next arrival position and heading angle of the vehicle based on the current front wheel steering angle control value, the current position of the vehicle, and the position of the preview point, where the position is the first prediction point of the predicted trajectory;

[0091] Specifically, according to formulas (7) to (9), we can obtain:

[0092]

[0093]

[0094]

[0095] In the formulas (14)-(16), l d0 is the Euclidean distance between the current position of the vehicle and the position of the preview point, δ0is the current front wheel steering control amount, L is the wheelbase of the vehicle, x ()→k is the horizontal coordinate of the first prediction point, y ()→k is the vertical coordinate of the first prediction point, ψ ()→k is the vehicle heading angle of the first prediction point.

[0096] As can be seen from the formulas (14)-(16), in the case where the vehicle speed is not considered to change, the pose of the first prediction point is only related to the current front wheel steering control amount.

[0097] The other prediction points in the prediction trajectory, except the first prediction point, are obtained according to the following manner:

[0098] The current front wheel steering control amount corresponding to the current prediction point and the trajectory point corresponding to the current prediction point in the planned trajectory are obtained, and the next position point reached by the vehicle and the vehicle heading angle are predicted according to the current front wheel steering control amount corresponding to the current prediction point, the position of the current prediction point and the position of the trajectory point corresponding to the current prediction point, the position point being the next prediction point of the prediction trajectory.

[0099] Specifically, according to the formulas (7)-(9), the following can be obtained:

[0100]

[0101]

[0102]

[0103] In the formulas (14)-(16), the current point of the vehicle is the i-th point on the prediction trajectory, l di is the Euclidean distance between the current prediction point of the vehicle and the trajectory point corresponding to the current prediction point, δ i is the current front wheel steering control amount corresponding to the current prediction point, L is the wheelbase of the vehicle, x ()→() is the horizontal coordinate of the next prediction point (i+1-th point), y ()→() is the vertical coordinate of the next prediction point (i+1-th point), ψ ()→() is the vehicle heading angle of the next prediction point (i+1-th point).

[0104] As can be seen from the formulas (17)-(19), in the case where the vehicle speed is not considered to change, the pose of the first prediction point is only related to the current front wheel steering control amount corresponding to the current prediction point.

[0105] The current front wheel steering control amount corresponding to the current prediction point is obtained according to the following manner:

[0106] determining a third front wheel turning angle required for the vehicle to move from the current prediction point to a trajectory point corresponding to the current prediction point based on the current minimum turning radius, determining a fourth front wheel turning angle required for the vehicle to move from the current prediction point to the trajectory point corresponding to the current prediction point based on the vehicle heading angle at the current prediction point and the vehicle heading angle at the trajectory point corresponding to the current prediction point, and determining a front wheel turning angle control amount corresponding to the current prediction point based on the third and fourth front wheel turning angles;

[0107] Determining the third front wheel turning angle required for the vehicle to move from the current prediction point to a trajectory point corresponding to the current prediction point according to the current minimum turning radius specifically includes:

[0108] According to formula (10), we can get:

[0109] According to the position of the current prediction point and the "track point corresponding to the current prediction point", the Euclidean distance l between the current prediction point and the "track point corresponding to the current prediction point" can be calculated. di According to formula (2), we can get: sinα=l di / 2R, further, the vehicle wheelbase is a known parameter, therefore, according to the Euclidean distance l di 、 The third front wheel turning angle δ can be calculated e_lati It should be noted that in this embodiment, the third front wheel turning angle required for the vehicle to move from the current prediction point to the corresponding trajectory point is determined based on the current minimum turning radius R. Controlling the lateral movement of the vehicle based on the third front wheel turning angle can effectively enable the vehicle to approach the corresponding trajectory point as quickly as possible.

[0110] The determining, based on the vehicle heading angle of the current prediction point and the vehicle heading angle of the trajectory point corresponding to the current prediction point, a fourth front wheel turning angle required for the vehicle to move from the current prediction point to the trajectory point corresponding to the current prediction point specifically includes:

[0111] Specifically, if the lateral motion of the vehicle is controlled solely based on the third front wheel steering angle, the vehicle's heading often does not match the planned direction of the trajectory point. Therefore, it is necessary to consider the heading correction simultaneously. First, the deviation value Δ between the vehicle heading angle of the current prediction point and the vehicle heading angle of the trajectory point corresponding to the current prediction point is calculated. ψi , further, the second front wheel turning angle δ can be calculated according to the following formula (20): e_headi ;

[0112]

[0113] In some embodiments, determining the front wheel angle control amount corresponding to the current prediction point based on the third front wheel angle and the fourth front wheel angle specifically includes:

[0114] The third front wheel steering angle and the fourth front wheel steering angle are weightedly summed, and the weighted summation result is corrected according to the steering angle correction coefficient to obtain the front wheel steering angle control amount corresponding to the current prediction point, as shown in the following formula (21);

[0115]

[0116] In formula (12), δ t is the current front wheel steering angle control value, is the third front wheel turning angle, is the fourth front wheel turning angle, W lati is the weight coefficient of the third front wheel turning angle, W eadi is the weight coefficient of the fourth front wheel turning angle.

[0117] In some embodiments, determining the front wheel angle control amount corresponding to the current prediction point based on the third front wheel angle and the fourth front wheel angle specifically further includes:

[0118] Obtain a lateral deviation between a current prediction point and a trajectory point corresponding to the current prediction point, and determine weight coefficients of the third and fourth front wheel turning angles based on the lateral deviation; wherein the lateral deviation is positively correlated with the weight coefficient of the third front wheel turning angle, and the lateral deviation is negatively correlated with the weight coefficient of the fourth front wheel turning angle.

[0119] Specifically, the lateral deviation between the current prediction point and the trajectory point corresponding to the current prediction point is e lati , W lati is a lateral deviation e lati The function can be expressed as W lati =f1(e lati ), the larger the lateral error, the larger the coefficient, and vice versa, the smaller the coefficient, W headi and e lati There is a positive correlation;

[0120] W headi It is also the lateral error e lati The function can be expressed as W headi =f2(e lati ), but the trend is opposite, that is, the larger the lateral error, the smaller the coefficient, and vice versa. headi and e lati There is a negative correlation.

[0121] In some embodiments, selecting a trajectory point from the planned trajectory as a preview point based on the current minimum turning radius specifically includes:

[0122] Obtaining a current vehicle speed, looking up a table to obtain a maximum front wheel turning angle corresponding to the current vehicle speed, and obtaining a minimum turning radius based on the maximum front wheel turning angle;

[0123] With the minimum turning radius as a constraint condition, a trajectory point closest to the current vehicle position among the multiple trajectory points is selected as a preview point.

[0124] Specifically, this embodiment preliminarily uses a real vehicle test method to draw a circle in place with the steering wheel fixed to obtain the turning radius of the trajectory. The corresponding wheel angle is calculated based on the geometric relationship of the turning radius. Through a series of different angles, a corresponding table of vehicle speed, maximum lateral acceleration, maximum front wheel angle, and steering wheel angle is obtained, resulting in the following MAP table:

[0125]

[0126] The maximum front wheel turning angle corresponding to the current vehicle speed can be obtained by querying the above MAP table;

[0127] Furthermore, with the minimum turning radius as a constraint condition, a circle is drawn with the turning radius as the radius. The point on the planned trajectory within the circle cannot be reached under the maximum allowable turning angle corresponding to the current vehicle speed. The nearest point on the planned trajectory that falls outside the circle should be selected as the preview point.

[0128] In some embodiments, the method further comprises:

[0129] A steering wheel angle is obtained based on the current front wheel angle control amount that meets the preset lateral deviation control requirements, and the steering wheel angle is low-pass filtered and output to a downstream module; the downstream module is used to control the lateral movement of the vehicle based on the steering wheel angle.

[0130] Specifically, this embodiment is calibrated based on real vehicle data. The steering wheel starts from the left limit and draws a circle in place. The trajectory radius is measured in increments of 10° each time until the right limit of the steering wheel is reached. The corresponding front wheel turning angle is calculated based on the geometric relationship of the turning radius: tanδ = L / R, and the corresponding relationship between the front wheel turning angle δ and the steering wheel angle ω is obtained as follows: Figure 4 , the fitted wheel ratio conversion formula is:

[0131] ω=k1δ 3 +k2δ 2 +k3δ+k4 (22)

[0132] In formula (22), k1, k2, k3, and k4 are all parameters calibrated according to actual vehicle data. According to formula (22), the front wheel angle δ can be converted into the corresponding steering wheel angle ω. Furthermore, the present application also provides a low-pass filter for low-pass filtering the converted steering wheel angle ω to prevent steering wheel shaking and abnormal control quantity. At this point, the single algorithm process ends, and the steps of the method of this embodiment can be repeated to achieve adaptive vehicle lateral control.

[0133] Another embodiment of the present application further provides a vehicle lateral control device, comprising a module for executing the vehicle lateral control method as described above.

[0134] It should be noted that the vehicle lateral control device of the above-mentioned embodiment corresponds to the vehicle lateral control method of the above-mentioned embodiment. Therefore, the parts of the vehicle lateral control device of the above-mentioned embodiment that are not described in detail can be obtained by referring to the contents of the vehicle lateral control method of the above-mentioned embodiment. That is, the specific steps recorded in the vehicle lateral control method of the above-mentioned embodiment can be understood as the functions that can be realized by the data packaging module and the data acquisition module of the above-mentioned embodiment, and will not be repeated here.

[0135] Furthermore, if the vehicle lateral control device of the above embodiment is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0136] Another embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the vehicle lateral control method as described in the above embodiment is implemented.

[0137] Specifically, the computer-readable storage medium may include: any entity or recording medium that can carry the computer program instructions, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0138] Another embodiment of the present application provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the vehicle lateral control method described in the above embodiment when executing the program.

[0139] Wherein, electronic equipment can also include the bus connecting different components (including memory and processor).Memory can include computer-readable medium in the form of volatile memory, such as random access memory (RAM) and / or cache memory.Memory can also include at least one program product, and this program product has one group (such as at least one) program module, and these program modules are configured to perform the function of each embodiment of the present application.Electronic equipment can also communicate with one or more external devices (such as keyboard, pointing device, display etc.), can also communicate with one or more devices that enable users to interact with this electronic equipment, and / or communicate with any device (such as network card) that enables this electronic equipment to communicate with one or more other computing devices, this communication can be carried out through input / output (I / O) interface, and electronic equipment can also communicate with one or more networks (such as local area network (LAN), wide area network (WAN) and / or public network, such as the Internet) through network adapter.

[0140] While various embodiments of the present application have been described above, the above descriptions are illustrative, non-exhaustive, and not intended to be limiting of the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A vehicle lateral control method, characterized in that: The method comprises: Selecting a trajectory point as a preview point from a planned trajectory according to the current minimum turning radius; the planned trajectory includes a plurality of trajectory points and a position and vehicle heading angle corresponding to each trajectory point; Determining a first front wheel turning angle required for the vehicle to move from a current vehicle position to the preview point according to the current minimum turning radius; Determining a second front wheel turning angle required for the vehicle to move from the current vehicle position to the preview point based on the current vehicle heading angle and the vehicle heading angle of the preview point; The current front wheel angle control amount is determined based on the first front wheel angle, the second front wheel angle, the front wheel angle control amount output last time, the current vehicle front wheel angle, and the angle correction coefficient. If the current front wheel angle control amount meets the preset lateral deviation control requirement, the current front wheel angle control amount is output.

2. The method according to claim 1, characterized in that The method further comprises: If the current front wheel steering angle control amount does not meet the preset lateral deviation control requirement, the steering angle correction coefficient is adjusted and the current front wheel steering angle control amount is re-determined until the current front wheel steering angle control amount that meets the preset lateral deviation control requirement is obtained and output.

3. The method according to claim 1, characterized in that The determining of the current front wheel angle control amount according to the first front wheel angle, the second front wheel angle, the front wheel angle control amount output last time, the current vehicle front wheel angle, and the angle correction coefficient specifically includes: The first front wheel angle, the second front wheel angle, the front wheel angle control value output last time, and the current vehicle front wheel angle are weightedly summed, and the weighted summation result is corrected according to the angle correction coefficient to obtain the current front wheel angle control value.

4. The method according to claim 3, characterized in that The determining of the current front wheel angle control amount according to the first front wheel angle, the second front wheel angle, the front wheel angle control amount output last time, the current vehicle front wheel angle, and the angle correction coefficient specifically includes: The weight coefficients of the first front wheel steering angle and the second front wheel steering angle are determined based on the lateral deviation between the current vehicle position and the preview point; wherein the lateral deviation is positively correlated with the weight coefficient of the first front wheel steering angle, and the lateral deviation is negatively correlated with the weight coefficient of the second front wheel steering angle.

5. The method according to claim 1, wherein Whether the current front wheel steering angle control value meets the preset lateral deviation control requirement is determined in the following manner: Assuming that the current front wheel steering angle control amount is valid, the predicted trajectory of the vehicle is predicted based on the current front wheel steering angle control amount, and whether an unexpected overshoot occurs is determined according to the lateral deviation between the predicted trajectory and the planned trajectory. If not, the current front wheel steering angle control amount meets the preset lateral deviation control requirement. If so, the current front wheel steering angle control amount does not meet the preset lateral deviation control requirement.

6. The method according to claim 5, characterized in that The predicting of the vehicle trajectory based on the current front wheel steering angle control amount, and determining whether an unexpected overshoot occurs according to a lateral deviation between the predicted trajectory and the planned trajectory, specifically includes: The predicted trajectory includes a plurality of predicted points; If the lateral deviations between the plurality of prediction points and the plurality of trajectory points corresponding thereto do not exceed the expected overshoot, then the current front wheel steering angle control amount meets the preset lateral deviation control requirement; If a lateral deviation between at least one of the plurality of prediction points and a corresponding trajectory point exceeds an expected overshoot, the current front wheel steering angle control amount does not meet a preset lateral deviation control requirement.

7. The method according to claim 6, characterized in that The first predicted point of the predicted trajectory is obtained by predicting the next position point and vehicle heading angle to be reached by the vehicle based on the current front wheel steering angle control value, the current position of the vehicle, and the position of the preview point, and the position point is the first predicted point of the predicted trajectory; All predicted points except the first predicted point in the predicted trajectory are obtained in the following manner: obtaining the front wheel steering angle control value corresponding to the current predicted point and the trajectory point corresponding to the current predicted point in the planned trajectory, and predicting the next arrival position and vehicle heading angle of the vehicle based on the front wheel steering angle control value corresponding to the current predicted point, the position of the current predicted point, and the position of the trajectory point corresponding to the current predicted point, with the position point being the next predicted point in the predicted trajectory; The front wheel steering angle control amount corresponding to the current prediction point is obtained according to the following method: determining the third front wheel steering angle required for the vehicle to move from the current prediction point to the trajectory point corresponding to the current prediction point according to the current minimum turning radius, determining the fourth front wheel steering angle required for the vehicle to move from the current prediction point to the trajectory point corresponding to the current prediction point according to the vehicle heading angle of the current prediction point and the vehicle heading angle of the trajectory point corresponding to the current prediction point, and determining the front wheel steering angle control amount corresponding to the current prediction point according to the third front wheel steering angle and the fourth front wheel steering angle.

8. The method according to claim 7, characterized in that The determining of the front wheel steering angle control amount corresponding to the current prediction point according to the third front wheel steering angle and the fourth front wheel steering angle specifically includes: The third front wheel steering angle and the fourth front wheel steering angle are weightedly summed, and the weighted summation result is corrected according to the steering angle correction coefficient to obtain the front wheel steering angle control amount corresponding to the current prediction point.

9. The method according to claim 8, characterized in that The determining of the front wheel steering angle control amount corresponding to the current prediction point according to the third front wheel steering angle and the fourth front wheel steering angle specifically further includes: Obtain a lateral deviation between a current prediction point and a trajectory point corresponding to the current prediction point, and determine weight coefficients of the third and fourth front wheel turning angles based on the lateral deviation; wherein the lateral deviation is positively correlated with the weight coefficient of the third front wheel turning angle, and the lateral deviation is negatively correlated with the weight coefficient of the fourth front wheel turning angle.

10. The method according to claim 1, characterized in that The step of selecting a trajectory point as a preview point from the planned trajectory according to the current minimum turning radius specifically includes: Obtaining a current vehicle speed, looking up a table to obtain a maximum front wheel turning angle corresponding to the current vehicle speed, and obtaining a minimum turning radius based on the maximum front wheel turning angle; With the minimum turning radius as a constraint condition, a trajectory point closest to the current vehicle position among the multiple trajectory points is selected as a preview point.

11. The method according to any one of claims 1 to 10, characterized in that The method further comprises: A steering wheel angle is obtained based on the current front wheel angle control amount that meets the preset lateral deviation control requirements, and the steering wheel angle is low-pass filtered and output to a downstream module; the downstream module is used to control the lateral movement of the vehicle based on the steering wheel angle.

12. A vehicle lateral control device, characterized in that: The invention comprises a module for executing the vehicle lateral control method according to any one of claims 1 to 11.

13. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the vehicle lateral control method according to any one of claims 1 to 11 is implemented.

14. An electronic device comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the vehicle lateral control method according to any one of claims 1 to 11 is implemented.

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