Method and control unit for a system for controlling a motor vehicle

Abstract

A method for controlling a motor vehicle (10) traveling on a roadway (12) in a current lane (14) is described, wherein the roadway (12) has at least one additional lane (16) that is adjacent to the current lane (14) of the motor vehicle (10). The method has the following steps: Multiple different driving maneuvers are generated and/or received. At least two driving maneuver classes that are defined based on at least one characteristic variable of the driving maneuvers are determined, wherein the driving maneuvers of various driving maneuver classes differ by at least one characteristic variable. The driving maneuvers are classified in one of the at least two driving maneuver classes. In addition, a control unit (30) for controlling a motor vehicle (10) is described.

Claims

1. A method for controlling a motor vehicle (10) traveling on a roadway (12) in a current lane (14), wherein the roadway (12) has at least one additional lane (16) that is adjacent to the current lane (14) of the motor vehicle (10), having the following steps: generating and/or receiving multiple different driving maneuvers each joining common points (A, B) together; determining at least two driving maneuver classes that are defined based on at least one characteristic variable of the driving maneuvers, wherein the driving maneuvers of various driving maneuver classes differ by at least one characteristic variable; classifying the driving maneuvers joining the common points (A, B) together in one of the at least two driving maneuver classes, wherein a homotopy analysis of the multiple driving maneuvers is carried out in order to assign the multiple driving maneuvers to a driving maneuver class and/or to determine a driving maneuver parameter of the at least one characteristic variable, wherein the driving maneuvers that can be transformed into one another without crossing an obstacle are classified in the same driving maneuver class; selecting one of the possible driving maneuvers based on the classification; and controlling the motor vehicle (10) according to the selected driving maneuver.

2. The method according to claim 1, wherein at least one characteristic variable includes at least one traffic sequence that indicates the time sequence of traveling past and/or overtaking by other road users.

3. The method according to claim 2, wherein the at least one traffic sequence includes an overtaking sequence, wherein the overtaking sequence includes at least one point in time at which the motor vehicle (10) is overtaking a further road user (18, 20).

4. The method according to claim 3, wherein the overtaking sequence includes multiple time-ordered points in time at which the motor vehicle (10) is in each case overtaking a further road user (18, 20).

5. The method according to claim 2, wherein the at least one traffic sequence includes a passing-by sequence, wherein the passing-by sequence includes at least one point in time at which a further road user (22) is traveling past the motor vehicle in the opposite direction or in the travel direction.

6. The method according to claim 5, wherein the passing-by sequence (22) includes multiple time-ordered points in time at which a further road user (22) is in each case traveling past the motor vehicle (10) in the opposite direction or in the travel direction.

7. The method according to claim 1, wherein the at least one characteristic variable includes information concerning a lane in which the motor vehicle (10) is situated after completion of the driving maneuver.

8. The method according to claim 1, wherein the driving maneuver parameter contains information at least concerning whether the motor vehicle (10) is overtaking the at least one further road user (18, 20, 22) on the left, is overtaking the at least one further road user (18, 20, 22) on the right, is traveling behind the at least one further road user (18, 20, 22), is traveling in front of the at least one further road user (18, 20, 22), or whether the at least one further road user (18, 20, 22) is traveling past the motor vehicle (10).

9. The method according to claim 1, wherein the multiple different driving maneuvers are generated randomly, pseudorandomly, and/or based on a predefined probability distribution.

10. The method according to claim 1, wherein at least the current lane (14) and/or the at least one additional lane (16) are/is transformed into a Frenet-Serret coordinate system.

11. The method according to claim 1, wherein the multiple different driving maneuvers and/or the driving maneuver classes are filtered based on at least one feasibility criterion, at least one comfort criterion, and/or at least one safety criterion.

12. The method according to claim 1, wherein driving maneuvers that belong to the same homotopy class are grouped in the same driving maneuver class and driving maneuvers that are not in the same homotopy class are grouped in a different driving maneuver class.

13. The method according to claim 1, wherein the driving maneuvers that cannot be transformed into one another without crossing the obstacle are classified in a separate driving maneuver class than the driving maneuvers that can be transformed into one another without crossing the obstacle.

14. A control unit (30) for a system (26) for controlling a motor vehicle (10) or for a motor vehicle (10), wherein the control unit (30) is designed to carry out a method according to claim 1.

15. A motor vehicle (10) having a control unit (30) according to claim 14.

16. A computer program having program code means for carrying out the steps of a method according to claim 1 when the computer program is executed on a computer or a processing unit (34) of a control unit (30) designed to carry out the method according to claim 1 .

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and characteristics of the invention result from the following description and the appended drawings, to which reference is made. In the drawings:

(2) FIG. 1a schematically shows a traffic situation;

(3) FIGS. 1b through 1d show various possible driving maneuvers of a motor vehicle;

(4) FIG. 2 shows a schematic block diagram of a motor vehicle according to the invention, having a system for controlling the motor vehicle;

(5) FIG. 3 shows a flow chart of the steps of a method according to the invention;

(6) FIGS. 4a and 4b schematically show a roadway prior to a transformation into a Frenet-Serret coordinate system, and after a transformation into a Frenet-Serret coordinate system, respectively;

(7) FIGS. 5a and 5b each show a diagram of possible space-time trajectories which in each case correspond to a driving maneuver of the motor vehicle;

(8) FIG. 6 schematically shows a decision tree representation of a driving maneuver parameter; and

(9) FIG. 7 shows an illustration of a homotopy analysis according to the method according to the invention.

DESCRIPTION

(10) FIG. 1 schematically shows a traffic situation in which a motor vehicle 10 is traveling on a roadway 12 in a current lane 14. Next to the current lane 14 is an additional lane 16.

(11) In the example shown in FIG. 1, the additional lane 16 is a lane for oncoming traffic. However, the additional lane may also be a further lane in the travel direction of the motor vehicle 10, for example if the roadway 12 is designed as an expressway.

(12) Also traveling on the roadway 12 in addition to the motor vehicle 10 are a first further road user 18 and a second further road user 20 in the current lane 14, and a third further road user 22 in the additional lane 16. In the example shown, the further road users 18, 20, 22 are passenger vehicles, although they could also be trucks, motorcycles, or any other given road users.

(13) The first further road user 18 and the second further road user 20 are traveling in the same lane as the motor vehicle 10 and in the same direction as the motor vehicle. The third further road user 22 is traveling toward the motor vehicle 10 in the additional lane 16.

(14) FIG. 1 also shows a coordinate system having a longitudinal axis and a perpendicular axis, the longitudinal axis defining a longitudinal direction L and the perpendicular axis defining a transverse direction N. The origin of the coordinate system lies in the longitudinal direction L at the current position of the very front of the motor vehicle 10, and on the right edge of the road, viewed in the longitudinal direction L.

(15) This particular coordinate system, which is also used for the following discussion, is a coordinate system which is fixed to the roadway, and which therefore does not move with the motor vehicle 10. Of course, any other given coordinate system may also be used.

(16) The dashed line 24 indicates that the motor vehicle 10 in the near future is planning to overtake the first further road user 18 and the second further road user 20. As shown in FIGS. 1(b) through 1(d), there are multiple different options for this driving maneuver.

(17) Thus, as shown in FIG. 1(b), the motor vehicle 10 may initially allow the third further road user to travel past before overtaking the first and the second further road user 18, 20.

(18) FIG. 1(c) shows a variant of the driving maneuver according to which the motor vehicle 10 initially overtakes the first further road user 18, then allows the third further road user to travel past, and then overtakes the second further road user 20.

(19) In contrast, FIG. 1(d) shows a variant of the driving maneuver in which the motor vehicle 10 overtakes the first and the second further road user 18, 20 before the third further road user 22 travels past the motor vehicle 10.

(20) The motor vehicle 10 is designed to automatically determine possible driving maneuvers in a given traffic situation, select one of the possible driving maneuvers, and automatically carry out the selected driving maneuver. The driving maneuver variants described above with reference to FIG. 1 are used in the following discussion strictly as an illustrative example.

(21) As shown in FIG. 2, the motor vehicle 10 has a system 26 for controlling the motor vehicle 10. The system 26 includes multiple sensors 28 and at least one control unit 30.

(22) The sensors 28 are situated at the front, rear and/or sides of the motor vehicle 10, and are designed to detect the surroundings of the motor vehicle 10, generate corresponding surroundings data, and relay the data to the control unit 30. More precisely, the sensors 28 detect information at least concerning the current lane 14, the additional lane 16, and the further road users 18, 20, 22.

(23) The sensors 28 are in each case a camera, a radar sensor, a distance sensor, a lidar sensor, and/or another type of sensor that is suitable for detecting the surroundings of the motor vehicle 10.

(24) Alternatively or additionally, at least one of the sensors 28 may be designed as an interface with a guidance system that is associated at least with the section of the roadway 12 that is shown, and that is designed to transmit surroundings data to the motor vehicle 10 and/or to the further road users 18, 20, 22 via the roadway 12 and/or via the further road users. The one sensor 28 in this case may be designed as a mobile radio communication module, for example for communication according to the 5G standard.

(25) In general, the control unit 30 processes the surroundings data received from the sensors 28 and controls the motor vehicle 10 based on the processed surroundings data, in an at least partially automatic manner, in particular completely automatically. Thus, a driving assistance system is implemented on the control unit 30 which is able to control a transverse motion and/or a longitudinal motion of the motor vehicle 10 in an at least partially automatic manner, in particular completely automatically.

(26) For this purpose, the control unit 30 is designed to carry out the method steps explained below with reference to FIGS. 3 through 7. More precisely, the control unit 30 includes a data medium 32 and a processing unit 34, a computer program being stored on the data medium 32 and being executed on the processing unit 34, and the program code including means for carrying out the steps of the method explained below.

(27) To allow all driving situations to be treated equally regardless of the current traffic conditions, the roadway 12, more precisely, a representation of the current lane 14 and of the additional lane 16, based on surroundings data obtained from the sensors 28, is transformed into a Frenet-Serret coordinate system (step S1).

(28) Step S1 is illustrated in FIG. 4. FIG. 4(a) shows the roadway 12 as it actually runs. In the example shown, the roadway, viewed in the longitudinal direction L, curves to the left. As the result of a local coordinate transformation the roadway 12 is transformed into the Frenet-Serret coordinate system, in which the roadway 12 is no longer curved, the result of this transformation being shown in FIG. 4(b). As is clearly apparent, in this coordinate system the roadway 12 runs straight, without a curve, along the longitudinal direction L.

(29) Multiple different driving maneuvers are now generated and/or received by the control unit 30 (step S2).

(30) As illustrated in FIG. 5, the driving maneuvers are space-time trajectories of the motor vehicle 10, more precisely, space-time trajectories in an X-Y-t coordinate system, where X corresponds to the longitudinal direction L and Y corresponds to the transverse direction N. In particular, these are thus space-time trajectories of the motor vehicle 10 in an L-N-t coordinate system.

(31) The various driving maneuvers are generated randomly, pseudorandomly, or based on a predefined probability distribution. The motor vehicle 10 is represented as a point mass, and accelerations of this point mass are simulated.

(32) Obstacles such as the further road users 18, 20, 22 are taken into account in generating the possible driving maneuvers, and are illustrated by dashed lines in FIG. 5. In particular, the obstacles are taken into account at least insofar as the space-time trajectories of the motor vehicle 10 and the space-time trajectories of the obstacles must not intersect or touch.

(33) In particular, a diffusion strategy is used in step S2 in order to obtain a greater diversity of the driving maneuvers. When the driving maneuvers are generated, those space-time trajectories already having a large number of other space-time trajectories in their vicinity are suppressed. In other words, this diffusion strategy also generates space-time trajectories, and thus, driving maneuvers, in areas in the X-Y-t coordinate system that are less densely populated by driving maneuvers. In this way, a plurality of different possible driving maneuvers are thus obtained in step S2. The result from step S2 is illustrated in FIG. 5(a).

(34) Next, the multiple various driving maneuvers are each classified in one of at least two different driving maneuver classes (step S3).

(35) The driving maneuver classes are defined in each case by a set of characteristic variables. The characteristic variables are variables that describe the essential features of the particular driving maneuver.

(36) The driving maneuver classes are disjunct; i.e., each driving maneuver is associated with only one driving maneuver class. Accordingly, driving maneuvers from two various different maneuver classes differ by at least one characteristic variable, or even by all characteristic variables. Driving maneuvers within a driving maneuver class may differ in one characteristic variable, but not in all characteristic variables.

(37) Conversely, the characteristic variables of the individual possible driving maneuvers that are obtained may be determined in order to classify the driving maneuvers in the various driving maneuver classes

(38) The characteristic variables include one or more of the following variables: a traffic sequence, an overtaking sequence, a passing-by sequence, a driving maneuver parameter, and/or information concerning the lane in which the motor vehicle 10 is situated after completion of the driving maneuver in question.

(39) The traffic sequence indicates the time sequence in which the other road users 18, 20, 22 are traveling past the motor vehicle 10.

(40) More precisely, the traffic sequence includes the overtaking sequence, which includes one or more time-ordered points in time at which the motor vehicle 10 is in each case overtaking a further road user (the first and the second further road user 18, 20 in the example in FIG. 1).

(41) In addition, the traffic sequence includes the passing-by sequence, which includes one or more time-ordered points in time at which other road users (the third further road user 22 in the example in FIG. 1) are traveling past the motor vehicle 10.

(42) Furthermore, the passing-by sequence also includes the information concerning whether the further road users are traveling past the motor vehicle 10 in the opposite direction or in the travel direction of the motor vehicle 10.

(43) In the example shown in FIG. 1, the information concerning the lane in which the motor vehicle 10 is situated after completion of the driving maneuver in question indicates whether the motor vehicle 10 is once again situated in the current lane 14, or instead in the additional lane 16, after completion of the driving maneuver.

(44) The driving maneuver parameter includes information concerning whether the motor vehicle 10 is overtaking the particular further road user on the left, is overtaking the particular further road user on the right, is traveling behind the particular further road user, is traveling in front of the particular further road user, or whether the at least one further road user is traveling past the motor vehicle 10 in the opposite direction or in the travel direction of the motor vehicle 10.

(45) FIG. 6 illustrates the driving maneuver parameter for the example from FIG. 1. The driving maneuver parameter is represented here as a decision tree, which for the three further road users 18, 20, 22 indicates in each case whether the motor vehicle 10 is overtaking them on fhe left (OL), overtaking them on fhe right (OR), traveling behind them (F), traveling in front of them (L), or whether they are traveling past the motor vehicle in the opposite direction or in the travel direction of the motor vehicle 10 (P).

(46) In order to determine one or more of the characteristic variables and to classify the driving maneuvers, a homotopy analysis of the multiple driving maneuvers, more precisely, of the space-time trajectories corresponding to the multiple driving maneuvers, is preferably carried out.

(47) In other words, those driving maneuvers whose associated space-time trajectories are homotopic relative to one another are classified in the same driving maneuver classes.

(48) In contrast, driving maneuvers whose associated space-time trajectories are not homotopic relative to one another are classified in different driving maneuver classes.

(49) FIG. 7 shows an illustration of the homotopy analysis that is simplified to two dimensions. In the figure, τ.sub.1, τ.sub.2, and τ.sub.3 denote three space-time trajectories, each of which joins points A and B together. In addition, an obstacle H is present through which the trajectories τ.sub.1, τ.sub.2, τ.sub.3 are not allowed to extend.

(50) The trajectories τ.sub.1 and τ.sub.2 are homotopic relative to one another, since they may be continuously deformed into one another, i.e., transformed into one another, without crossing an obstacle. Therefore, the trajectories τ.sub.1 and τ.sub.2 are classified in the same driving maneuver class.

(51) In contrast, τ.sub.3 is not homotopic relative to τ.sub.1 and τ.sub.2, since τ.sub.3 cannot be continuously transformed into τ.sub.1 or τ.sub.2 without crossing the obstacle H. Therefore, the trajectory τ.sub.3 is classified in a different driving maneuver class than τ.sub.1 and τ.sub.2.

(52) One specific option for the homotopy analysis is provided by the following steps:

(53) A space-time trajectory is initially associated with each obstacle. In addition, a hypothetical current having a predefined current intensity is sent through each of the space-time trajectories of the obstacles, the current intensities being the same for all space-time trajectories of the obstacles.

(54) For the space-time trajectories τ.sub.i, each of which corresponds to a driving maneuver, the so-called h signature h(τ.sub.i) is then determined, which as a line integral is defined via the magnetic field B, generated by the hypothetical currents, along τ.sub.1:
h(τ.sub.i)=∫.sub.τ.sub.iB({right arrow over (l)}).Math.d{right arrow over (l)}.

(55) It has been found that space-time trajectories τ.sub.i that belong to the same homotopy class, and thus to the same driving maneuver class, have the same h signature. Accordingly, the various generated driving maneuvers may be classified in the driving maneuver classes by determining their h signature.

(56) From each driving maneuver class, one, in particular exactly one, representative space-time trajectory together with the corresponding characteristic variables is now stored on the data medium 32 (step S4) and optionally relayed to an optimization and decision module of the control unit 30. The result from step S4 is shown in FIG. 5(b).

(57) The optimization and decision module then optionally optimizes one of the representative driving maneuvers and/or selects one of the representative driving maneuvers, according to which the motor vehicle 10 is then automatically controlled by the control unit 30 (step S5).

(58) For this purpose, it may be provided that the representative driving maneuvers are also filtered based on predefined criteria, i.e., removed before or after the optimization.

(59) The predefined criteria are feasibility criteria, comfort criteria, and/or safety criteria.

(60) One example of a feasibility criterion is whether the motor vehicle can even reach a certain space-time region based on a maximum acceleration or a maximum deceleration of the motor vehicle.

(61) One example of a comfort criterion is whether the acceleration in the longitudinal and/or transverse direction exceeds a predefined limit value which, based on experience, is perceived as uncomfortable by the vehicle occupants.

(62) One example of a safety criterion is a minimum distance to be maintained from other road users, or a speed limit.