Vehicle transverse control method and device, storage medium and electronic equipment

Abstract

The invention relates to a vehicle transverse control method and device, a storage medium and electronic equipment. The method comprises the steps that a track point is selected from a planned track according to the current minimum turning radius to serve as a preview point; according to the current minimum turning radius, a first front wheel turning angle needed by the vehicle to move from the current vehicle position to the preview point is determined; according to the current vehicle course angle and the vehicle course angle of the preview point, determining a second front wheel turning angle required by the vehicle to move from the current vehicle position to the preview point; according to the first front wheel rotation angle, the second front wheel rotation angle, the front wheel rotation angle control amount output last time, the current vehicle front wheel rotation angle and the rotation angle correction coefficient, the current front wheel rotation angle control amount is determined, and whether the current front wheel rotation angle control amount is legal or not is judged; if yes, outputting the current front wheel steering angle control quantity; and if not, adjusting the rotation angle correction coefficient until the legal current front wheel rotation angle control quantity is obtained, and outputting the legal current front wheel rotation angle control quantity. According to the invention, control precision and computing power overhead can be considered in vehicle transverse 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 an important development trend in the automotive industry, and an important manifestation of intelligence is autonomous driving. The autonomous driving of vehicles includes lateral control and longitudinal control, among which lateral control is an important task of trajectory tracking. According to the different modeling methods of vehicle models, it is divided into two types: dynamic model and kinematic model.

[0003] There are mainly MPC algorithm and LQR algorithm based on dynamic model. MPC algorithm and LQR algorithm can consider position and orientation errors at the same time. LQR algorithm and MPC algorithm mostly need optimization algorithm to find the optimal solution in the corresponding time domain while considering the position and heading following. 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 takes up almost no computing power, but can only follow waypoints and does not follow the heading, so 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 is different in different scenarios and is difficult to calibrate. Therefore, the PurePursuit algorithm and the Stanley algorithm have low computing power overhead, but their 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 take into account both 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 object, 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 the planned trajectory according to the current minimum turning radius; the planned trajectory includes a plurality of trajectory points and a position and a 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] Determine 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;

[0011] The current front wheel angle control amount is determined 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. 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 steering angle control amount according to the first front wheel steering angle, the second front wheel steering angle, the front wheel steering angle control amount output last time, the current vehicle front wheel steering angle, and the steering angle correction coefficient specifically includes:

[0015] The first front wheel steering angle, the second front wheel steering angle, the front wheel steering angle control value output 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.

[0016] In some embodiments, determining the current front wheel steering angle control amount according to the first front wheel steering angle, the second front wheel steering angle, the front wheel steering angle control amount output last time, the current vehicle front wheel steering angle, and the steering angle correction coefficient specifically includes:

[0017] The lateral deviation between the current vehicle position and the preview point is used to determine the weight coefficients of the first front wheel turning angle and the second front wheel turning angle according to the lateral deviation; wherein the lateral deviation is positively correlated with the weight coefficient of the first front wheel turning angle, and the lateral deviation is negatively correlated with the weight coefficient of the second front wheel turning angle.

[0018] In some solutions, whether the current front wheel steering angle control amount 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 according to 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 have an overshoot exceeding the expected amount, 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 in the following manner: according to the current front wheel steering angle control amount, the current position of the vehicle, and the position of the preview point, the next position point to be reached by the vehicle and the vehicle heading angle are predicted, and the position point is the first predicted point of the predicted trajectory;

[0025] The predicted points except the first predicted point in the predicted trajectory are obtained in the following manner: the front wheel steering angle control amount corresponding to the current predicted point and the trajectory point corresponding to the current predicted point in the planned trajectory are obtained, and the next arrival position and vehicle heading angle of the vehicle are predicted according to the front wheel steering angle control amount 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, and the position point is the next predicted point of 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 according to 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, the 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 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 front wheel turning angle and the fourth front wheel turning angle according to 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 according to 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 according to the maximum front wheel turning angle;

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

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

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

[0036] An embodiment of the present application also 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, and 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 its device, storage medium, and electronic device, which determines a preview point according to a current minimum turning radius and multiple trajectory points provided by a planned trajectory, and determines 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. The first front wheel turning angle can effectively make the vehicle approach the preview point as quickly as possible, but the first front wheel turning angle is prone to overshoot due to a short preview distance. Therefore, the embodiment of the present application also determines 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, and determines the current front wheel turning angle control amount according to the first front wheel turning angle, the second front wheel turning angle, the front wheel turning angle control amount output last time, the current vehicle front wheel turning angle, and the turning angle correction coefficient. The second front wheel turning angle can simultaneously take into account the tracking of the vehicle heading, ensure that the vehicle can follow the waypoint according to the heading of the planned trajectory, and can effectively alleviate the overshoot caused by the short preview distance. Finally, it is determined whether the current front wheel turning angle control amount meets the preset lateral deviation control requirement; if so, the current front wheel turning angle control amount is output. Compared with the MPC algorithm and the LQR algorithm, which must use an iterative approach to optimize the state matrix solution method, the embodiment of the present application only performs numerical judgment, which can greatly reduce the computing power occupied, and achieves a balance between balancing computing power and improving control effect. It can not only realize the prediction function, but also reduce the computing power overhead caused by the use of a linear solution algorithm, and ultimately achieve an ideal control effect. By reducing computing power expenses, the computing power requirements for the controller are greatly reduced, and it is more suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 The present invention is a flow chart of a vehicle lateral control method in one embodiment of the present application.

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

[0043] Figure 3 A schematic diagram of a planned trajectory and a predicted trajectory in one embodiment of the present application.

[0044] Figure 4 This is a schematic diagram of the correspondence between the front wheel angle and the steering wheel angle in an embodiment of the present application. DETAILED DESCRIPTION

[0045] The detailed description of the drawings is intended 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, referring to 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 need to be tracked by the vehicle 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, the Ackerman turning angle is ignored and a single-vehicle model is adopted. The wheelbase of the vehicle is L, the front wheel turning angle is δ, O is the starting point, the speed of the vehicle at the starting point is v0, R is the turning radius, and O′ is a time d t The position of the rear vehicle, where t Assuming that the vehicle speed remains unchanged and the vehicle moves forward in the original speed direction, 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 can obtain the vehicle's position (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 preview point position. 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 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 according to the current minimum turning radius, and controlling the lateral movement of the vehicle according to 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 according to step S20 alone to control the lateral movement of the vehicle, the heading of the vehicle often does not match the planned direction of the trajectory point, so it is necessary to consider the heading correction simultaneously, that is, 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 according to 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, there is no unexpected overshoot, 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 this embodiment determines the preview point according to the current minimum turning radius and multiple trajectory points provided by the planned trajectory, and determines the 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. The first front wheel turning angle can effectively make the vehicle approach the preview point as quickly as possible, but the first front wheel turning angle is prone to overshoot due to the short preview distance; therefore, the method of this embodiment also determines the 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, and determines the second front wheel turning angle required for the vehicle to move from the current vehicle position to the preview point according to the first front wheel turning angle, the second front wheel turning angle, and the last input The current front wheel steering angle control amount is determined by the output front wheel steering angle, the current vehicle front wheel steering angle, and the steering angle correction coefficient. The second front wheel steering angle can take into account the tracking of the vehicle heading at the same time, ensuring that the vehicle can follow the waypoint in the heading of the planned trajectory, and can effectively alleviate the overshoot caused by the short preview distance; finally, determine whether the current front wheel steering angle control amount meets the preset lateral deviation control requirements; if so, output the current front wheel steering angle control amount; if not, adjust the steering angle correction coefficient and re-determine the current front wheel steering angle control amount until the current front wheel steering angle control amount that meets the preset lateral deviation control requirements is obtained and output. Compared with the MPC algorithm and the LQR algorithm, which must use an iterative method to optimize the state matrix, the method of this embodiment only performs numerical judgment, which can greatly reduce the computing power occupied. The method of this embodiment achieves a balance between balancing computing power and improving control effect. It can not only realize the prediction function, but also reduce the computing power overhead caused by the use of a linear solution algorithm, ultimately achieving an ideal control effect and reducing computing power expenses. The computing power requirements for the controller are greatly reduced, making it more suitable for mass production.

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

[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 re-determined until the current front wheel steering angle control amount that meets 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 front wheel steering angle control amount is corrected again 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 output to the downstream module for controlling the lateral movement of the vehicle.

[0074] In some embodiments, the step S40 determines 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 including:

[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 turning 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 steering angle.

[0078] In some embodiments, the step S40 determines 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, and specifically includes:

[0079] The lateral deviation between the current vehicle position and the preview point is used to determine the weight coefficients of the first front wheel turning angle and the second front wheel turning angle according to the lateral deviation; wherein the lateral deviation is positively correlated with the weight coefficient of the first front wheel turning angle, and the lateral deviation is negatively correlated with the weight coefficient of the second front wheel turning angle.

[0080] Specifically, W lat0 is a lateral deviation e lat0 The function can be expressed as W lat0 =f1(e lat0), the larger the lateral error, the larger the coefficient, and vice versa, the smaller the coefficient, W head0 and e lat0 There is a positive correlation;

[0081] W head0 It is also the lateral error e lat0 The function can be expressed as W head0 =f2(e lat0 ), but the trend is opposite, that is, the larger the lateral error, the smaller the coefficient, and vice versa. head0 and e lat0 There is a negative correlation.

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

[0083] 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 ε occurs according to the lateral deviation between the predicted trajectory and the planned trajectory k 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.

[0084] Specifically, assuming that the current front wheel steering angle control amount is effective, the future trajectory of the vehicle under the control of the current front wheel steering angle control amount can be predicted according to the current state of the vehicle, and the trajectory points corresponding to the predicted trajectory and the planned trajectory are, Figure 3 Two trajectories are shown, Figure 3 The left track is the planned track output by the vehicle planning module (solid line). Figure 3 The trajectory on the right is the predicted trajectory (dashed line), which has 9 predicted points, namely the k+1~k+9th points on the predicted trajectory, the kth point on the predicted trajectory is the point where the vehicle is currently located, and the planned trajectory also has 9 trajectory points, namely the k+1~k+9th points on the planned trajectory, and there is also a preview point on the planned trajectory, and the k+1~k+9th points on the predicted trajectory are in one-to-one correspondence with the k+1~k+9th points on the planned trajectory; in this embodiment, the lateral deviation between the predicted trajectory and the planned trajectory refers to the lateral deviation between the two points, that is, the lateral deviation between the predicted point on the predicted trajectory and the corresponding trajectory point on the planned trajectory; the expected overshoot ε k It refers to the maximum deviation of the control system in the actual operation that exceeds the expected transition process, the overshoot ε k It is usually expressed as a percentage or absolute value, which reflects the degree of oscillation generated during the system response process; 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, the 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 according to 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 multiple trajectory points corresponding thereto 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 determined 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 a judgment is made as to whether the lateral deviation between the next prediction point and a corresponding trajectory point exceeds 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] According to the current front wheel steering angle control amount, the current position of the vehicle, and the position of the preview point, predict the next position point to be reached by the vehicle and the vehicle heading angle, and the position point 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 formulas (14) to (16), l d0 is the Euclidean distance between the current position of the vehicle and the position of the preview point, δ0 is the current front wheel steering angle control value, L is the vehicle wheelbase, x ()→k is the horizontal coordinate of the first prediction point, y ()→k is the ordinate of the first predicted point, ψ ()→k is the vehicle heading angle of the first prediction point;

[0096] It can be seen from formulas (14) to (16) that, without considering the change in vehicle speed, the position of the first prediction point is only related to the current front wheel steering angle control value.

[0097] Among them, the predicted points except the first predicted point in the predicted trajectory are obtained according to the following method:

[0098] Obtain the front wheel steering angle control amount corresponding to the current prediction point and the trajectory point corresponding to the current prediction point in the planned trajectory, and predict the next arrival position point and vehicle heading angle of the vehicle according to the front wheel steering angle 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, and the position point is the next prediction point of the predicted trajectory;

[0099] Specifically, according to formulas (7) to (9), we can obtain:

[0100]

[0101]

[0102]

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

[0104] It can be seen from formulas (17) to (19) that, without considering the change in vehicle speed, the position of the first prediction point is only related to the front wheel steering angle control value corresponding to the current prediction point.

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

[0106] Determine 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 according to the current minimum turning radius, determine 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 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 determine a front wheel turning angle control amount corresponding to the current prediction point according to the third front wheel turning angle and the fourth front wheel turning angle;

[0107] The step of 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 "trajectory point corresponding to the current prediction point", the Euclidean distance l between the current prediction point and the "trajectory 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 according to the current minimum turning radius R, and controlling the lateral movement of the vehicle according to the third front wheel turning angle can effectively make the vehicle approach the corresponding trajectory point as quickly as possible.

[0110] The determining, 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, the 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 movement of the vehicle is controlled based on the third front wheel steering angle alone, 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 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:

[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, the 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 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 front wheel turning angle and the fourth front wheel turning angle according to 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 according to 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 according to the maximum front wheel turning angle;

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

[0124] Specifically, this embodiment preliminarily uses a real vehicle test method to fix the steering wheel and draw a circle in place to obtain the turning radius of the trajectory, and calculates the corresponding wheel angle through 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 to obtain 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, taking 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 according to a current front wheel steering angle control amount that meets a preset lateral deviation control requirement, and the steering wheel angle is low-pass filtered and then output to a downstream module; the downstream module is used to control the lateral movement of the vehicle according to the steering wheel angle.

[0130] Specifically, this embodiment is calibrated according to the actual vehicle data. The steering wheel starts from the left limit and draws a circle in place. The trajectory radius is measured with an increment of 10° each time until the right limit of the steering wheel. The corresponding front wheel turning angle is calculated by the geometric relationship of the turning radius: tanδ=L / R, and then 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; further, 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 are continuously 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 embodiment corresponds to the vehicle lateral control method of the above embodiment. Therefore, the part of the vehicle lateral control device of the above embodiment that is not described in detail can be obtained by referring to the content of the vehicle lateral control method of the above embodiment, that is, the specific steps recorded in the vehicle lateral control method of the above embodiment can be understood as the functions that can be realized by the data packaging module and the data acquisition module of the above embodiment, which 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, and 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, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0138] Another embodiment of the present application 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 described in the above embodiment when executing the program.

[0139] Wherein, the electronic device may also include a bus connecting different components (including memory and processor). The memory may include a computer-readable medium in the form of a volatile memory, such as a random access memory (RAM) and / or a cache memory. The memory may also include at least one program product, which has a set of (e.g., at least one) program modules, which are configured to perform the functions of the various embodiments of the present application. The electronic device may also communicate with one or more external devices (e.g., keyboards, pointing devices, displays, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device, and / or communicate with any device (e.g., a network card) that enables the electronic device to communicate with one or more other computing devices, such communication may be performed through an input / output (I / O) interface, and the electronic device may also communicate with one or more networks (e.g., local area networks (LANs), wide area networks (WANs) and / or public networks, such as the Internet) through a network adapter.

[0140] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill 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 the planned trajectory according to the current minimum turning radius; the planned trajectory includes a plurality of trajectory points and a position and a 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; Determine 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; The current front wheel angle control amount is determined 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. 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 method of determining the current front wheel steering angle control amount according to the first front wheel steering angle, the second front wheel steering angle, the front wheel steering angle control amount output last time, the current vehicle front wheel steering angle, and the steering angle correction coefficient specifically includes: The first front wheel steering angle, the second front wheel steering angle, the front wheel steering angle control value output 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.

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

5. The method according to claim 1, characterized in that Whether the current front wheel steering angle control amount 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's predicted 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 have an overshoot exceeding the expected amount, 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 in the following manner: according to the current front wheel steering angle control amount, the current position of the vehicle, and the position of the preview point, the next position point to be reached by the vehicle and the vehicle heading angle are predicted, and the position point is the first predicted point of the predicted trajectory; The predicted points except the first predicted point in the predicted trajectory are obtained in the following manner: the front wheel steering angle control amount corresponding to the current predicted point and the trajectory point corresponding to the current predicted point in the planned trajectory are obtained, and the next arrival position and vehicle heading angle of the vehicle are predicted according to the front wheel steering angle control amount 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, and the position point is the next predicted point of 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 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 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: 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 front wheel turning angle and the fourth front wheel turning angle according to 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 from the planned trajectory as a preview point 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 according to the maximum front wheel turning angle; Taking the minimum turning radius as a constraint condition, a trajectory point among the multiple trajectory points that is closest to the current vehicle position 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 according to a current front wheel steering angle control amount that meets a preset lateral deviation control requirement, and the steering wheel angle is low-pass filtered and then output to a downstream module; the downstream module is used to control the lateral movement of the vehicle according to 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, characterized in that: 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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