CN-116353634-B - Method for compensating automatic driving transverse deviation caused by tire pressure problem

CN116353634BCN 116353634 BCN116353634 BCN 116353634BCN-116353634-B

Abstract

The invention provides a method for compensating automatic driving transverse deviation caused by tire pressure, which comprises the following steps of S1, collecting motion information of a tire in a vehicle running process in real time, S2, calculating the rolling radius of the tire according to the motion information of the tire, judging whether the tire pressure is abnormal or not through a radius iteration method, wherein the radius iteration method is to represent the difference of the rolling radius of the tire through preset characteristic parameters gamma so as to judge whether the tire pressure is abnormal or not, S3, judging the relationship between the tire pressure and the tire radius according to the rolling radius of the tire and the characteristic parameters gamma, and determining the abnormal tire position of the tire pressure, and S4, calculating a compensation value of a steering wheel angle according to the characteristic parameters gamma.

Inventors

Zhou Fangrui
PENG YIFAN
YAO MINGJIE
LU YISHEN

Assignees

上汽大众汽车有限公司

Dates

Publication Date: 20260505
Application Date: 20230414

Claims (9)

1. A method for compensating for lateral deviation of automatic driving caused by tire pressure problem, comprising the steps of: step S1, acquiring the movement information of a tire in the running process of a vehicle in real time, wherein the movement information of the tire comprises the linear speed and the angular speed of the tire rolling; step S2, calculating the rolling radius of the tire according to the motion information of the tire, and judging whether the tire pressure of the tire is abnormal or not through a radius iteration method, wherein the radius iteration method is to judge whether the tire pressure of the tire is abnormal or not by representing the difference of the rolling radius of the tire through a preset characteristic parameter gamma; Step S3, judging the relation between the tire pressure and the tire radius according to the rolling radius and the characteristic parameter gamma of the tire, and determining the abnormal tire position of the tire pressure, and Step S4, calculating a compensation value of the steering wheel angle according to the characteristic parameter gamma; in step S2, when the characteristic parameter γ remains in a state other than 0, the tire pressure is abnormal, and the preset calculation formula of the characteristic parameter γ is as follows: (1) Where R FL represents the roll radius of the left front wheel, R FR represents the roll radius of the right front wheel, R RL represents the roll radius of the left rear wheel, and R RR represents the roll radius of the right rear wheel.
2. The method for compensating for the lateral deviation of automatic driving caused by the tire pressure problem according to claim 1, wherein the rolling radius of the tire during the running of the vehicle is calculated as follows: (2) Where R represents the rolling radius of the tire, V R represents the linear speed of the tire rolling, and ω R represents the angular speed of the tire rolling.
3. The method for compensating for the lateral deviation of automatic driving caused by the tire pressure problem according to claim 2, wherein in the step S2, when the rolling radius R is a constant value, the calculation formula of the characteristic parameter γ is as follows: (3) Wherein V FL represents the linear velocity of the left front wheel, V FR represents the linear velocity of the right front wheel, V RL represents the linear velocity of the left rear wheel, V RR represents the linear velocity of the right rear wheel, ω FL represents the angular velocity of the left front wheel, ω FR represents the angular velocity of the right front wheel, ω RL represents the angular velocity of the left rear wheel, ω RR represents the angular velocity of the right rear wheel.
4. A method for compensating for the lateral deviation of automatic driving caused by the tire pressure problem according to claim 3, wherein the step S2 further comprises the step of iteratively solving the characteristic parameter γ in the formula (3) by using a recursive least square method, and the specific steps are as follows: (4) Wherein a=1; ; ; (5) (6) (7) (8) wherein, p and A satisfy the relation: (9) The termination conditions for the iteration are: (10) Wherein, the In order to terminate the limit value, Is the value at the time of iteration convergence 。
5. The method for compensating for the lateral deviation of automatic driving caused by the tire pressure problem according to claim 2, wherein the step S3 is specifically: Calculating the rolling radius of each tire by the formula (2), calibrating according to the tire radius and the characteristic parameter gamma, and judging the relation between the tire pressure and the tire radius; the rolling radii of the respective tires are compared, and the tire position where the tire pressure abnormality occurs is determined.
6. The method for compensating for the lateral deviation of the automatic driving caused by the tire pressure problem according to claim 1, wherein in the step S4, when the tire pressure of the single side in the coaxial tire is insufficient, the compensation value of the steering wheel angle is calculated according to the characteristic parameter γ.
7. The method for compensating for the lateral deviation of the automatic driving caused by the tire pressure problem according to claim 6, wherein the step S4 is specifically: when the tire pressure difference of the coaxial tire exceeds 0.1kpa, calculating a compensation value of the steering wheel angle according to the characteristic parameter gamma, otherwise, not compensating.
8. The method for compensating for the lateral deviation of automatic driving caused by the tire pressure problem according to claim 6 or 7, wherein the formula for calculating the compensation value of the steering wheel angle in the step S4 is as follows: (11) Wherein, the Gamma is the characteristic parameter calculated in the step S2, and under different tire movement information, gamma is a dynamic value; As a differential pressure coefficient, carrying out dynamic calibration according to the tire pressure conditions under different conditions; for the calibration factor, the expected value is reached by adjustment, and lat_error is the lateral error.
9. The method for compensating for the lateral deviation of automatic driving caused by the tire pressure problem according to claim 8, wherein the differential pressure coefficient in the formula (11) is dynamically calibrated when the tire pressure abnormality occurs simultaneously in the tires on the same side And the calculation formula of the characteristic parameter gamma is as follows: (12) Wherein omega FL represents the angular velocity of the left front wheel, omega FR represents the angular velocity of the right front wheel, and the transverse error lat_error is continuously converged to 0 according to the compensation value of the steering wheel angle so as to calibrate the error.

Description

Method for compensating automatic driving transverse deviation caused by tire pressure problem Technical Field The invention relates to the field of automatic driving vehicles, in particular to a method for compensating automatic driving transverse deviation caused by tire pressure. Background Along with development and continuous development of unmanned, in the process of unmanned control algorithm development and real vehicle test, the situation that the unmanned vehicle has insufficient steering of a curve caused by insufficient tire pressure is encountered. This occurrence is very dangerous for an unmanned vehicle. Due to long-term testing and use of vehicles, it is very common for phenomena such as tire pressure reduction, tire wear, etc. to occur. Therefore, a method for solving the above problems is needed. There are two solutions to the above problems in the art. The first is to prevent the problem of flat tire or other tire conditions by remotely monitoring the tire pressure of the L4 level unmanned vehicle, so as to avoid threatening the safety of the autonomous vehicle. And secondly, the vehicle is allowed to run for a period of time, the cornering stiffness after the tire pressure change is calculated through related parameters, and then a certain amount of deviation is repaired through the parameter cornering stiffness according to the unmanned vehicle under the two-degree-of-freedom modeling. However, both of the above methods have several drawbacks. The first method is only to make a function of preventing the tire pressure problem in advance, and still requires manual tire pressure supplement to ensure the running of the vehicle. In the second method, since the unmanned automobile algorithm mostly builds an automobile kinematic model (bicycle model) through a two-degree-of-freedom model, when one of the tire pressures is too low in the coaxial direction, the radii of the coaxial tires are not equal any more, so that the two-degree-of-freedom model is broken at a certain critical point. Therefore, it may not be sufficient to compensate the output of the steering wheel angle in the algorithm by only the parameter of cornering stiffness. Furthermore, autonomous vehicles may experience deviations due to differences in vehicle tire radius. And this method is not applied to the field of L4 class unmanned driving. In summary, in the testing and developing process, the method for solving the above problem by only reminding the driver to timely inflate the tire with lower tire pressure or replace the tire with serious wear may be suitable for low-level unmanned (L2 and below), and does not need to consider various complex scenes and dangerous situations. The method cannot ensure that the unmanned vehicle can accurately run according to the planned track, and potential safety hazards exist in the running process. For high-level unmanned, in particular L4 level unmanned, extreme cases in special scenarios must also be taken into account. Disclosure of Invention The invention aims to provide a method for compensating the automatic driving transverse deviation caused by the tire pressure problem so as to avoid the problem of paranoid caused by breaking a two-degree-of-freedom model when the single tire pressure is too low. The method obtains characteristic parameters according to the movement information of the tires under different tire pressures and the rolling radius of each tire, the characteristic parameters can be changed along with tire pressure change, the change condition of the rolling radius of each tire is judged according to the characteristic parameters and the movement information of tire rolling so as to position the low-pressure tire, and meanwhile, the problem of steering wheel understeer is solved by continuously testing steering wheel steering errors under different parameters according to the change condition of tire pressure, tire angular speed, vehicle speed, tire radius and the like. In order to achieve the above object, the present invention provides a method for compensating for a lateral deviation of an automatic driving caused by a tire pressure problem, comprising the steps of: step S1, acquiring the movement information of a tire in the running process of a vehicle in real time, wherein the movement information of the tire comprises the linear speed and the angular speed of the tire rolling; step S2, calculating the rolling radius of the tire according to the motion information of the tire, and judging whether the tire pressure of the tire is abnormal or not through a radius iteration method, wherein the radius iteration method is to judge whether the tire pressure of the tire is abnormal or not by representing the difference of the rolling radius of the tire through a preset characteristic parameter gamma; Step S3, judging the relation between the tire pressure and the tire radius according to the rolling radius and the characteristic parameter gamma of the tire, and determ