Method for steering a vehicle

Patent metadata

Field	Value
Publication number	US-2016200359-A1
Application number	US-201414912560-A
Country	US
Kind code	A1
Filing date	Aug 14, 2014
Priority date	Aug 29, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

For steering a vehicle around obstacles, proceeding along a path from a starting position to an end position, the path including linear sub-paths which are defined by an increment η and a steering angle δ, a method includes: a) determining a maximum steering angle range and a maximum and a minimum increment range; b) determining the present distance e P from the end position, the target angle θ O , and the angle difference e θ between the present vehicle angle and the target angle; c) performing an optimization method for ascertaining a sub-path by minimizing the value of a cost function l O assigned to the sub-path; d) determining the new position by adding the ascertained sub-path to the present position; and e) repeating steps (b) through (d) until the end position is reached.

First claim

1 - 13 . (canceled)

14 . A method for steering a vehicle around at least one obstacle, the vehicle being steered along a path extending from a starting position to an end position, wherein the path includes multiple linear sub-paths which are each defined by an increment η and a steering angle δ, the method comprising:
a) determining a maximum steering angle range, a maximum increment range, and a minimum increment range;
b) determining a present distance e P from the end position, a target angle θ O , and an angle difference e θ between a present vehicle angle θ and the target angle θ O ;
c) carrying out an optimization method for ascertaining a linear sub-path by minimizing the value of a cost function l O assigned to the linear sub-path, wherein:
(i) the cost function includes the present distance e P from the end position and the present angle difference e θ to the target angle as optimization variables which are weighted independently of each other, and
(ii) the maximum steering angle range, the maximum increment range, the minimum increment range, and a collision test are provided as boundary conditions;

d) determining a new position by adding the ascertained linear sub-path to the present position; and
e) repeating steps (b) through (d) until the end position is reached.

15 . The method as recited in claim 14 , wherein the entire path to the end point is initially calculated, and subsequently the vehicle is steered along the path.

16 . The method as recited in claim 14 , wherein the vehicle is steered along the calculated linear sub-paths during the calculation of the overall path to the end point.

17 . The method as recited in claim 14 , wherein the method is divided into at least two phases as a function of the position of one corner of the vehicle relative to at least two obstacles, a target angle θ O =α which is essentially normal to a boundary line between the at least two obstacles being selected in a first phase.

18 . The method as recited in claim 14 , wherein the method is divided into at least two phases as a function of the position of one corner of the vehicle relative to at least two obstacles, a target angle θ O =α which is essentially parallel to the longitudinal extension of the at least two obstacles being selected in a first phase.

19 . The method as recited in claim 14 , wherein the method is divided into at least two phases as a function of the position of one corner of the vehicle relative to at least two obstacles, a target angle θ O =θ S which is essentially parallel to a boundary line between the at least two obstacles being selected in a second phase.

20 . The method as recited in claim 17 , wherein the at least two phases differ by weighting factors of the optimization variables.

21 . The method as recited in claim 20 , wherein the method is divided into two phases A and B, and wherein:
a) in phase A, the weighting of the present distance e P from the end position outweighs the weighting of the angle difference e θ to the target angle to quickly move the vehicle in the direction of the end position; b) in phase B, the weighting of the angle difference e θ to the target angle outweighs the weighting of the distance e P from the end position to bring the vehicle into the correct angular position; and c) a switch is carried out between phase A and phase B at a switching point as soon as the position of one corner of the vehicle passes through a boundary line between the at least two obstacles.

22 . The method as recited in claim 20 , wherein, during the optimization method, points of change in direction are determined at which the direction of the sub-path to be determined is changed, the points of change in direction being defined as points at which one of:
a) no sub-path is ascertainable whose associated cost function is improved compared to the previously ascertained sub-path; or b) no sub-path is ascertainable whose increment is within the allowed increment range.

23 . The method as recited in claim 21 , wherein, during the optimization method, points of change in direction are determined at which the direction of the sub-path to be determined is changed, the points of change in direction being defined as points at which one of:
a) in phase A, no sub-path is ascertainable whose associated cost function is improved compared to the previously ascertained sub-path; or b) in phase B, no sub-path is ascertainable which is within the allowed increment range.

24 . A non-transitory, computer-readable data storage medium storing a computer program having program codes which, when executed on a computer, perform a method for steering a vehicle around at least one obstacle, the vehicle being steered along a path extending from a starting position to an end position, wherein the path includes multiple linear sub-paths which are each defined by an increment η and a steering angle δ, the method comprising:
a) determining a maximum steering angle range, a maximum increment range, and a minimum increment range;
b) determining a present distance e P from the end position, a target angle θ O , and an angle difference e θ between a present vehicle angle θ and the target angle θ O ;
c) carrying out an optimization method for ascertaining a linear sub-path by minimizing the value of a cost function l O assigned to the linear sub-path, wherein:
(i) the cost function includes the present distance e P from the end position and the present angle difference e θ to the target angle as optimization variables which are weighted independently of each other, and
(ii) the maximum steering angle range, the maximum increment range, the minimum increment range, and a collision test are provided as boundary conditions;

d) determining a new position by adding the ascertained linear sub-path to the present position; and
e) repeating steps (b) through (d) until the end position is reached.

25 . A control system for steering a vehicle around at least one obstacle, the vehicle being steered along a path extending from a starting position to an end position, wherein the path includes multiple linear sub-paths which are each defined by an increment η and a steering angle δ, the control system comprising:
a detection system including sensors for ascertaining the starting position, the end position, the steering angle δ, the vehicle angle θ, and the coordinates of the at least one obstacle; and
a control unit including a processor configured to perform the following:
a) determining a maximum steering angle range, a maximum increment range, and a minimum increment range;
b) determining a present distance e P from the end position, a target angle θ O , and an angle difference e θ between a present vehicle angle θ and the target angle θ O ;
c) carrying out an optimization method for ascertaining a linear sub-path by minimizing the value of a cost function l O assigned to the linear sub-path, wherein:
(i) the cost function includes the present distance e P from the end position and the present angle difference e θ to the target angle as optimization variables which are weighted independently of each other, and
(ii) the maximum steering angle range, the maximum increment range, the minimum increment range, and a collision test are provided as boundary conditions;

d) determining a new position by adding the ascertained linear sub-path to the present position; and
e) repeating steps (b) through (d) until the end position is reached.

Assignees

• Bosch Gmbh Robert

Inventors

• Boeck Martin
• Kugi Andreas
• Zips Patrik

Classifications

• B62D15/025 Primary

  Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation (B62D1/28 takes precedence) · CPC title

• B62D15/027 Primary

  Parking aids, e.g. instruction means · CPC title

• B62D15/0285 Primary

  Parking performed automatically · CPC title