METHOD FOR ASSISTING A DRIVER IN MANEUVERING A MOTOR-VEHICLE COMBINATION

Abstract

The invention relates to a method for assisting a driver in maneuvering a motor-vehicle combination (1) comprising, as vehicles, at least one tractor motor vehicle (2) and at least two trailers (3a, 3b) coupled thereto, wherein a target articulation angle (γ.sub.2) at least between two of the vehicles (3a, 3b) is externally specified and is adjusted by means of at least one steering actuator (5a, 5b) of at least one of the vehicles (2). The method comprises at least the following steps: a) dividing the motor-vehicle combination (1) into at least two sub-combinations (1a, 1b) in such a way that adjacent vehicles (2, 3a, 3b) form a sub-combination (1a, 1b) in pairs, in which sub-combination a first vehicle is used as a trailer unit (3a, 3b) and a second vehicle is used as a tractor vehicle unit (2, 3a), at least virtually; b) repeatedly determining a target angle (α, γ.sub.1, γ.sub.2) for a number of consecutive sub-combinations (1a, 1b) from a specified target articulation angle (γ.sub.1, γ.sub.2) between the tractor vehicle unit (2, 3a) and the trailer unit (3a, 3b), beginning with the sub-combination (1a) whose target articulation angle (γ.sub.2) was specified externally, wherein: —the determined target angle is adjusted as a target steering angle (α) for the tractor vehicle unit (2) of the sub-combination (1b) by means of the at least one steering actuator (5a, 5b) of the associated vehicle (2) if the tractor vehicle unit (2) has the at least one steering actuator (5a, 5b), or—the determined target angle is specified as the target articulation angle (γ.sub.1) for the next sub-combination (1b).

Claims

1. A method for assisting a driver when maneuvering a motor vehicle combination (1) comprising as vehicles at least one towing vehicle (2) and at least two trailers (3a,3b) that are coupled thereto, wherein a target articulation angle (γ.sub.2) between at least two of the vehicles (3a,3b) is specified externally and is applied by at least one steering actuator (5a,5b) of at least one of the vehicles (2), comprising at least the following process steps: a) subdividing the motor vehicle combination (1) into at least two sub-combinations (1a, 1b) such that adjacent vehicles (2,3a,3b) in pairs form a sub-combination (1a, 1b), in which, at least virtually, a first vehicle is used as the trailer unit (3a,3b) and a second vehicle is used as the towing vehicle unit (2,3a); b) repeated determination of a target angle (α, γ.sub.1, γ.sub.2) for a number of successive sub-combinations (1a, 1b) from a specified target articulation angle (γ.sub.1, γ.sub.2) between the towing vehicle unit (2,3a) and the trailer unit (3a,3b), starting at the sub-combination (1a) of which the target articulation angle (γ.sub.2) has been externally specified, wherein: the determined target angle is applied as the target steering angle (α) for the towing vehicle unit (2) of the sub-combination (1b) by the at least one steering actuator (5a,5b) of the associated vehicle (2) if the towing vehicle unit (2) comprises the at least one steering actuator (5a,5b), or the determined target angle is specified as the target articulation angle (γ.sub.1) for the next sub-combination (1b).

2. The method as claimed in claim 1, wherein step b) is ended if the target steering angle (α) for the towing vehicle (2) of the motor vehicle combination (1) has been applied by the at least one steering actuator (5a,5b).

3. The method as claimed in claim 1, wherein a stand-alone sub-controller is associated with each sub-combination (1a, 1b), and the stand-alone sub-controller determines the target angle (α, γ.sub.1) from the specified target articulation angle (γ.sub.1, γ.sub.2) between the towing vehicle unit (2,3a) and the trailer unit (3a,3b) of the sub-combination (1a,1b).

4. The method as claimed in claim 3, wherein the target articulation angle (γ.sub.1, γ.sub.2) between the towing vehicle unit (2,3a) and the trailer unit (3a,3b) of the sub-combination (1a, 1b) is specified externally or obtained from the sub-controller of the previous sub-combination (1a,1b).

5. The method as claimed in claim 3, wherein the sub-controllers of the sub-combinations (1a, 1b) in series form an overall controller or cascade controller for determining the target steering angle (α) of the towing motor vehicle (2) of the motor vehicle combination (1) from the externally specified target articulation angle (γ.sub.2).

6. The method as claimed in claim 1, wherein the externally specified target articulation angle (γ.sub.2) is obtained from an input unit by a user.

7. The method as claimed in claim 1, wherein the at least one steering actuator (5a,5b) of the at least one vehicle (2) applies a yaw torque and comprises at least one steerable wheel (5a,5b).

8. The method as claimed in claim 1, wherein signals from articulation angle sensors of the vehicles (2,3a,3b) are used.

9. The method as claimed in claim 1, wherein vehicles (3a) that are not disposed at the front or at the rear of the motor vehicle combination (1) are part of two different sub-combinations (1a, 1b).

10. A control unit of a towing vehicle (2) for a motor vehicle combination (1) that is arranged for carrying out a method as claimed in claim 1.

11. The method as claimed in claim 1, wherein the externally specified target articulation angle (γ.sub.2) is obtained from an input unit by an automatic driver assistance system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] An exemplary embodiment of the invention is described in principle below using the drawings:

[0028] In the figures:

[0029] FIG. 1 shows a schematic representation of a motor vehicle combination comprising a towing vehicle and two trailers coupled thereto in series;

[0030] FIG. 2 shows a schematic representation of a first sub-combination of the motor vehicle combination; and

[0031] FIG. 3 shows a schematic representation of a second sub-combination of the motor vehicle combination.

DETAILED DESCRIPTION

[0032] Functionally identical elements are provided with the same reference characters in the figures.

[0033] A motor vehicle combination 1 comprising as vehicles a towing motor vehicle 2 and two trailers 3a, 3b that are coupled thereto in series is shown in FIG. 1 for clarification of a method according to the invention. The wheels of the vehicles 2, 3a, 3b are provided with the reference character 5. The towing vehicle 2 comprises as a steering actuator a steering system that is not represented, which for example can be implemented as EPS (electric power steering) or AFS (active front steering), and wheels 5a, 5b that are steerable by the same. The steerable wheels 5a, 5b are considered here in a highly simplified way as a steering actuator. There is an articulation angle γ.sub.2 between the trailer 3b and the trailer 3a. There is an articulation angle γ.sub.1 between the trailer 3a and the towing motor vehicle 2. The wheel turning angle of the towing motor vehicle 2 is denoted by α.

[0034] With the method according to the invention for assisting a driver when maneuvering the motor vehicle combination 1 comprising as vehicles the towing motor vehicle 2 and two trailers 3a, 3b that are coupled thereto, in particular in series, a target articulation angle γ.sub.2 between two of the vehicles 3a, 3b is specified externally and is applied by means of a steering actuator 5a, 5b of the towing motor vehicle 2. The method comprises at least the following process steps: [0035] a) subdividing the motor vehicle combination 1 into two sub-combinations 1a, 1b (see FIGS. 2 and 3) so that in pairs adjacent vehicles 2, 3a, 3b form the sub-combination 1a, 1b, in which at least virtually a first vehicle is used as a trailer unit 3a, 3b and a second vehicle is used as a towing vehicle unit 2, 3a; [0036] b) repeated determination of a target angle α, γ.sub.1, γ.sub.2 for a number of successive sub-combinations 1a, 1b from a specified target articulation angle γ.sub.1, γ.sub.2 between the towing vehicle unit 2, 3a and the trailer unit 3a, 3b, starting at the sub-combination 1a, the target articulation angle γ.sub.2 of which has been specified externally, wherein [0037] the determined target angle is applied as the wheel turning angle or target steering angle α for the towing vehicle unit 2 of the sub-combination 1b by means of the at least one steering actuator 5a, 5b of the associated vehicle 2 if the towing vehicle unit 2 comprises the at least one steering actuator 5a, 5b, or [0038] the determined target angle is specified as the target articulation angle γ.sub.1 for the next sub-combination 1b, in particular if the towing vehicle unit 3a of the sub-combination 1a does not comprise the at least one steering actuator.

[0039] Step b) of the method is ended if the target steering angle α for the towing motor vehicle 2 of the motor vehicle combination 1 has been applied by means of the steering actuator 5a, 5b.

[0040] As can be seen from FIG. 2, the articulation angle γ.sub.2 is specified as the target articulation angle for the sub-combination 1a. In FIG. 2 the trailer 3b is used as the trailer unit and the trailer 3a is virtually used as the towing vehicle unit, wherein a start was made at the rearmost trailer 3b. Because the virtual towing vehicle unit 3a in FIG. 2 has no dedicated steering actuator, the determined target angle is specified as the target articulation angle γ.sub.1 for the next sub-combination 1b (see FIG. 3). Said target articulation angle γ.sub.1 can be considered to be the virtual wheel turning angle of the rest of the vehicle combination or the virtual towing vehicle unit 3a. Then, as can be seen from FIG. 3, the target angle for the sub-combination 1b is calculated from the specified target articulation angle γ.sub.1. Here the trailer 3a is now used as the trailer unit and the towing motor vehicle 2 is used as the towing vehicle unit. Because the towing motor vehicle 2 or the towing vehicle unit comprises the steering actuator 5a, 5b, the target angle can be applied as the wheel turning angle or the target steering angle a by the steering actuator 5a, 5b.

[0041] There is a stand-alone sub-controller associated with each sub-combination 1a, 1b that determines the target angle α, γ.sub.1 from the specified target articulation angle γ.sub.1, γ.sub.2 between the towing vehicle unit 2, 3a and the trailer unit 3a, 3b of the sub-combination 1a, 1b.

[0042] The target articulation angle γ.sub.1, γ.sub.2 between the towing vehicle unit 2, 3a and the trailer unit 3a, 3b of the sub-combination 1a, 1b can be specified externally or obtained from the sub-controller of the previous sub-combination 1a, 1b.

[0043] The sub-controllers of the sub-combinations 1a, 1b in series can form an overall controller or cascade controller for determining the target steering angle α of the towing motor vehicle 2 of the motor vehicle combination 1 from the externally specified target articulation angle γ.sub.2. The present externally specified target articulation angle γ.sub.2 can be obtained from an input unit by a user or from an automatic driver assistance system. In a different exemplary embodiment, the target articulation angle γ.sub.1 could also be specified externally.

[0044] With the method according to the invention, signals from articulation angle sensors, which are not shown, of the vehicles 2, 3a, 3b can be used.

[0045] The method according to the invention can be performed in a control unit, which is not shown, of the towing vehicle 2 for the motor vehicle combination 1.

REFERENCE CHARACTER LIST

[0046] 1 motor vehicle combination

[0047] 1a, 1b sub-combinations

[0048] 2 towing motor vehicle

[0049] 3a, 3b trailers

[0050] 5 wheels

[0051] 5a, 5b steerable wheels

[0052] γ.sub.1, γ.sub.2 articulation angles

[0053] α target steering angle