Method and driver assistance system for reverse driving in vehicle combination, and motor vehicle

Abstract

The invention relates to a method and a driver assistance system for assisted reverse driving with a vehicle combination (1), in which first forward driving is carried out, in which a respective forward trajectory (4) is stored and an object (5) arranged beside the forward trajectory (4) is detected by a sensor system of a tractor (2). A backward path (7) is planned which deviates as little as possible from the traveled forward path (4) and a vehicle-specific backward corridor (8, 9) corresponding to the planned backward path (7) is planned for each vehicle (2, 3) in the vehicle group (1). Furthermore, if the object is located in at least one planned backward corridor (8, 9), the detected object (5) at the time is classified as a collision object (6). In this case, a new backward travel trajectory (7a) is generated and a new backward travel corridor (8a, 9a) without collision objects (6) is generated for each vehicle (2, 3). The vehicle group (1) then travels back along a new back travel path (7a) by means of a driver assistance system.

Description

Technical Field

[0001] The invention relates to a method for assisted reverse travel with a vehicle combination having a tractor and a trailer connected to the tractor, as well as a driver assistance system. Background Art

[0002] It is often difficult for unskilled drivers to drive a vehicle combination with a trailer connected to a tractor in reverse. Therefore, today, in modern motor vehicles, assistance systems are provided more and more frequently, which assist the driver to drive in reverse with a trailer. When driving forward, the steering axle is the front axle of the vehicle group, and the trailer is pulled along the driving direction. In contrast, when driving in reverse, the steering axle of the vehicle group is the rear axle of the vehicle group, and the trailer is pushed along the driving direction. The trailer usually has at least one rigid axle, which constitutes the first axle of the vehicle group when driving in reverse with the vehicle group. Therefore, when driving in reverse with the vehicle group, the tractor that plays a driving role must drive on a wider driving corridor in order to properly turn to the trailer that is hung (or connected), because the trailer has a low willingness to turn due to its rigid axle. Therefore, a driving trajectory for driving forward is generated for the tractor and the trailer, which is different from the driving trajectory for driving in reverse. It is often necessary to reverse the route that the vehicle group just drove forward as accurately as possible, for example, to allow oncoming traffic to pass through a narrow place or to reverse out of a narrow dead end entrance. However, due to different driving trajectories, objects that passed by when driving forward along the forward trajectory may be located as obstacles in the reverse trajectory when driving backward. Therefore, there is a need for a system to solve this problem.

[0003] Patent document US Pat. No. 10,775,805 B2 discloses a method in which a planned route for forward travel is provided to the control of a vehicle, wherein obstacles on the route are scanned during forward travel with the vehicle and the vehicle traveling forward is directed to bypass the obstacles if necessary.

[0004] Furthermore, patent document US 9 164 955 B2 proposes a method in which sensors of a vehicle combination arranged on the tractor and / or trailer are used to detect obstacles during reverse travel with the vehicle combination. If an obstacle is detected in the planned reverse travel trajectory, the reverse travel trajectory is changed and a change operation, such as intervention in the tractor control, is performed.

[0005] Patent document DE 10 2018 212 060 A1 discloses a method in which a vehicle is guided from a starting position to a target position with the aid of a planned reference trajectory. The reference trajectory is predetermined by a parking assistance system and includes a series of reference postures, each of which includes a vehicle position and a vehicle orientation. The area of ​​the reference posture to be driven in the future is monitored by the vehicle's environmental sensors. Based on the detection of an obstacle in the reference trajectory, one or more avoidance postures are determined, which are respectively located in a freely drivable area and are moved to the side of the obstacle relative to the reference trajectory, wherein the avoidance posture is obtained by laterally moving the reference posture relative to the reference trajectory and / or by inserting another posture. The avoidance trajectory determined in this way is then inserted into the reference trajectory, and the vehicle is controlled according to the new reference trajectory.

[0006] However, none of these conventional methods take into account the fact that driving in reverse with a trailer requires a wider driving corridor for the tractor that is pushing the trailer in order to properly turn the attached trailer. If sensors are used in conventional methods, they must be placed on the trailer, so conventional methods do not include vehicle groups with simple, sensorless trailers. It should be noted that the rear sensor system of the tractor is covered by the trailer, so that the rear sensor system of the tractor does not provide reliable data. Summary of the invention

[0007] The object of the present invention is to provide a solution for making assisted reverse travel with a vehicle combination particularly safe and as simple and labor-saving as possible for the human driver of the vehicle combination.

[0008] This technical problem is solved by the technical solution according to the present invention. Other feasible design solutions of the present invention are disclosed in the specification and the drawings.

[0009] According to the invention, a method for assisted reverse driving with a vehicle combination is proposed. The vehicle combination is referred to herein as a vehicle combination (or trailer combination) and comprises a tractor and a trailer connected to the tractor via a trailer coupling. One of the vehicles is equipped with a driver assistance system, which is configured for executing the method and also belongs to the invention. That is, in particular, the tractor has a driver assistance system. It is conceivable that the vehicle combination has a driver assistance system in such a way that one or some driver assistance system modules of the driver assistance system are arranged on the tractor and one or some driver assistance system modules of the same driver assistance system are arranged on the trailer. Alternatively or additionally, it is conceivable that one or some driver assistance system modules of the same driver assistance system are designed outside the vehicle combination, for example in the form of a module coupled to other driver assistance system modules for data transmission or as part of such a module. In addition, according to the invention, a motor vehicle, in particular a passenger car, is proposed, which has a driver assistance system and is configured to act as a tractor for the vehicle combination.

[0010] The method is in particular a method that can be implemented by a computer, which means that at least some of the method steps described in more detail below can be executed by a computer set up for electronic data processing. In this case, the present invention also proposes a computer program and a computer-readable storage medium, on which the computer program is stored. When the program instructions of the computer program are executed by the computer, the computer program causes the computer to execute a method for assisted reverse driving with a vehicle combination. The computer is in particular a driver assistance system or a module or a group of modules in a driver assistance system, optionally in combination with a computer device external to the vehicle combination. In addition, the present invention proposes a computer program, which, when the program instructions of the computer program are executed by a computer or a driver assistance system, causes the computer or the driver assistance system to execute a method for assisted reverse driving with a vehicle combination. Therefore, the driver assistance system module described below can be a software module or a program module of the computer program.

[0011] In a method for driving in reverse with assistance with a vehicle group, in step S1 of the method, the vehicle group first drives forward with assistance or without assistance (i.e. manually, purely by a human driver or fully or partially assisted by a driver assistance system). The corresponding forward trajectory of the vehicle group is stored in a driver assistance system, for example in a trajectory memory of the driver assistance system, which is implemented as a ring memory in a possible design. The forward trajectory of the vehicle group has a forward trajectory of the tractor and a forward trajectory of the trailer; however, since the two forward trajectories hardly deviate from each other when the vehicle group is moving forward (unlike when the vehicle group is moving in reverse), they are considered to coincide in a good approximation. Objects arranged beside the forward trajectory are detected by the sensor system of the tractor during the forward movement. The sensor system includes, for example, ultrasonic sensors, laser sensors, radar sensors, lidar sensors, infrared sensors and / or camera sensors. Sensor data collected by the sensor system and characterizing objects beside the forward trajectory are provided to the driver assistance system, in particular as a point cloud. The position of the object is thus stored, for example, in an object memory of the driver assistance system. During the forward travel or after the forward travel is finished, in step S2, for example, a reverse trajectory generation module of a driver assistance system is used to plan a reverse trajectory for the vehicle group and a corresponding vehicle-specific reverse corridor. The vehicle group or the reverse trajectory for the vehicle group is planned in this way so that the reverse trajectory deviates as little as possible from the forward trajectory of the vehicle group. Therefore, the forward trajectory is used as a reference trajectory for the upcoming reverse travel. A vehicle-specific reverse corridor corresponding to the reverse trajectory of the vehicle group is planned separately for each vehicle in the vehicle group. That is, a reverse corridor is planned for the tractor, and its own reverse corridor (or channel) is planned for the trailer. In step S3 of the method, the detected objects are classified, for example, by an object classification module of a driver assistance system. If the corresponding object is located in one or two planned reverse corridors, the detected object at that time is classified as a collision object. On the contrary, if the corresponding object is not located in any reverse corridor when the vehicle group is reversed, the detected object at that time can be classified as a non-collision object. Step S4 of the method provides that, when one or more detected objects are classified as collision objects, a new reverse trajectory for the vehicle group is generated by the reverse trajectory generation module and thus a new vehicle-specific reverse corridor is generated for each vehicle. The respective vehicle-specific new reverse corridor is generated so that it deviates as little as possible from the respective reverse corridor planned in step S2. However, the two new reverse corridors are at least generated so that the objects of the detected objects classified as collision objects are not located in any vehicle-specific new reverse corridor at this time.In step S5 of the method, the vehicle set is driven in reverse in a reverse assist operating mode, for example, executed by a vehicle control module of a driver assistance system, wherein the driver assistance system, in particular its vehicle control module, at least intervenes in the lateral guidance of the tractor vehicle in such a way that the vehicle set travels along a new reverse trajectory and thus travels through a new vehicle-specific reverse corridor. The driver assistance system can be switched to the reverse assist operating mode, for example, by the driver of the tractor vehicle making a corresponding input to the driver assistance system, for example giving a voice command or actuating a button, etc. By activating the reverse assist operating mode, in particular the vehicle control module of the driver assistance system is switched to active or assist operation.

[0012] In the method or by the driver assistance system, the forward trajectory of the vehicle group is recorded during the forward movement of the vehicle group. The driver can actually drive at will, and the trajectory traveled can be continuously recorded in the ring memory of the driver assistance system, for example. For example, the trajectory is always stored for a predetermined completed driving route length, such as the last 100m. The problem in the prior art that objects that pass by without collision during forward movement may cause a collision with the vehicle group when reversing along the forward trajectory is eliminated by this method. In addition, the method includes all possible trailers, because these trailers do not need to have any special equipment / equipment. Because during the assisted reverse movement, the driver assistance system does not (any longer) rely on the sensors of the vehicle group, because the reverse trajectory to be traveled has been acquired by the sensors during the previous forward movement. Usually, the rear sensors of the tractor are originally turned off when running together with the trailer, so as not to provide erroneous information to the driver. In particular, it is conceivable that the method uses a static map, and the driver assistance system intervenes in the lateral guidance of the tractor according to the static map. It is also conceivable that the driver is warned by the driver assistance system if the driver assistance system determines that the planned reverse maneuver cannot be carried out. Of course, in order to carry out the method, the geometrical properties of the tractor and trailer must be provided to the driver assistance system in advance. For example, the user can store the dimensions of the trailer in the driver assistance system via a human-machine interface. In addition, it can be provided that the user also enters the dimensions of the tractor into the driver assistance system, for example, if the tractor deviates from its standard dimensions due to additional equipment or load.

[0013] In a possible further development of the method, it is provided that during reverse travel, the entire new reverse trajectory is traveled at once, i.e. without forward corrective actions, and thus a new vehicle-specific reverse corridor is traveled. In other words, the new reverse trajectory or the new reverse corridor is planned in such a way that no forward corrective actions are required. If reverse travel is completely impossible or cannot be continued without forward corrective actions, it is provided in the method in particular that the assistance is stopped and control of the vehicle group is (re) completely handed over to the human driver, or the reverse assistance operating mode is not activated from the beginning (a prompt message is sent to the driver if necessary).

[0014] According to another possible embodiment, it is provided that in step S5 the driver assistance system completely takes over the transverse guidance of the tractor vehicle and / or the longitudinal guidance of the tractor vehicle. As a result, the human driver, as a possible source of error, cannot control the vehicle set at all when driving the vehicle set in reverse. This ensures, for example, that the driver does not complete the reverse movement too quickly, which could affect driving stability.

[0015] According to another possible embodiment, for each vehicle in the vehicle group, the driver assistance system is pre-assigned (vorgeben, or preset) a (first) imaginary collision rectangle, which completely surrounds the corresponding vehicle and moves with the vehicle. It is provided that the geometric area centroid of the collision rectangle lies on the longitudinal center axis (X axis) of the vehicle. In addition, the transverse axis (Y axis) of the vehicle and the transverse axis of the collision rectangle are arranged at least parallel to each other. For each vehicle, the collision rectangle is pre-assigned in particular such that the outer contour of the relevant vehicle and the edge of the collision rectangle are spaced apart from each other by a first safety distance, which is less than 75 cm, preferably less than 50 cm, in particular 25 cm. In addition, for each vehicle in the vehicle group, the driver assistance system is pre-assigned an imaginary circumscribed circle, on which the corner points of the relevant collision rectangle are always located. Therefore, like the collision rectangle, the circumscribed circle also moves with the corresponding vehicle when the vehicle is moved. In this embodiment, it is also provided that if one or both circumscribed circles intersect with the corresponding object during the forward movement, the detected object is respectively classified as a critical object, for example by an object classification module of the driver assistance system. If, on the other hand, the corresponding object does not intersect any vehicle circumcircle when passing by, the detected object at that time can be classified as a non-critical object. In step S3 of the method, only those detected objects that would intersect the collision rectangle during reverse travel assisted by the driver assistance system are classified as collision objects at that time. In this way, computing power can be saved because the number of objects to be classified is smaller than if all objects detected by the sensor system were classified, wherein in this case objects that are not relevant to the planning of a collision-free reverse travel are included.

[0016] In the extended design, it is provided that for each vehicle, a second imaginary collision rectangle which is completely within the first collision rectangle and a third imaginary collision rectangle which is completely within the second collision rectangle are pre-given. In particular, these collision rectangles are concentric with each other, that is, they have a common area centroid, which is located on the longitudinal center axis of the vehicle. In a possible extended design, the edge of the first collision rectangle and the outer contour of the relevant vehicle are spaced apart from each other by a first safety distance of, for example, 75 cm. The edge of the second collision rectangle and the edge of the first collision rectangle are spaced apart from each other by, for example, 25 cm, so that the edge of the second collision rectangle and the outer contour of the relevant vehicle are spaced apart from each other by a second safety distance of 50 cm. In addition, the edge of the third collision rectangle and the edge of the second collision rectangle are spaced apart from each other by, for example, 25 cm, so that the edge of the third collision rectangle and the outer contour of the relevant vehicle are spaced apart from each other by a third safety distance of 25 cm. This should only be understood as a possible example: other distances between the edges of the collision rectangles or between the collision rectangles and the outer contour of the relevant vehicle are of course also feasible. In this case, in the reverse driving assisted by the driver assistance system, as long as the corresponding collision object intersects with the first collision rectangle but does not intersect with the second collision rectangle or the third collision rectangle, the collision object at that time is classified as a prompt object, for example, by an object classification module. In response to the prompt object, a prompt operation is performed by the driver assistance system. For example, the driver is informed that the vehicle group is approaching the collision object and / or the driving speed of the vehicle group is reduced and / or the driver is proposed to fully or partially take over the control of the vehicle group again. In addition, in the process of assisted reverse driving, as long as the corresponding collision object intersects with the first collision rectangle and the second collision rectangle but does not intersect with the third collision rectangle, the collision object at that time is classified as a warning object, wherein, as a response to the warning object, a warning operation is performed by the driver assistance system. For example, the driver is informed that the vehicle group is facing a collision and / or the driving speed of the vehicle group is further / more reduced and / or the driver is advised to fully take over the control of the vehicle group again with higher urgency. If the collision object enters the innermost collision rectangle, that is, the third collision rectangle, a collision emergency operation can be performed. For example, the driver is informed that a collision is imminent and / or the train set is brought to a complete stop and / or control of the train set is fully returned to the driver. In this way, a three-stage warning system can be easily implemented, through which the driver of the train set can be informed more clearly of the potential risk and / or, in the case of automatic braking, the vehicle is gradually decelerated before the driver is surprised by the full braking.

[0017] In order to plan or generate a new reverse track or a vehicle-specific new reverse corridor, another possible implementation method stipulates that it is planned to drive out (Ausscheren) from the reverse track of the original plan. For this reason, a vertical line relative to the tangent of the reverse track that intersects with the outer contour point is set up on the problem point of the reverse track of the original plan in step S2, and the outer contour point of the reverse track and the collision object is spaced apart from each other by a minimum distance. Use the reverse track tangent that branches out from the reverse track in the problem point here. Subsequently, a new planning point is arranged in the straight line extension line of the vertical line on the side opposite to the outer contour point of the reverse track, wherein, a track offset distance is formed between the reverse track of the original plan and the new planning point. This track offset distance is at least greater than zero, but is still selected so that it is as close as possible to the reverse track of the original plan. At least during the first planning to drive out, the track offset distance is selected so long at most that it is possible to pass the problem point in a first-order approximation by the driver assistance system without collision with the vehicle group. In particular, the track offset distance is limited, more precisely, the sensor effective range of the sensor system of the tractor is limited, and the sensor effective range is vertically and horizontally about four meters respectively to the corresponding track ground of the tractor. In other words, the new planning point is arranged at most on the lateral outer boundary of the sensor effective range of the sensor system of the tractor. For example, if the vertical and horizontal sensor effective range of the sensor system is four meters, the track offset distance is at most four meters. Then determine the exit point on the original planned reverse track, and the exit point is located upstream of the problem point on the original planned reverse track with respect to the reverse direction. This means that if you continue to travel along the reverse track, the vehicle group will first arrive at the exit point and then arrive at the problem point. In step S4, for example, a new reverse track section is planned between the exit point and the new planning point by a reverse track generation module, and therefore a new reverse corridor section dedicated to each vehicle is planned for each vehicle, so as to drive out of the reverse track of the original plan.

[0018] If when planning a new reverse corridor section or a new reverse track section dedicated to a vehicle so as to drive out of the reverse track of the original plan, determine that traveling along these new reverse corridor sections will cause a secondary collision, then in a possible extended design, it is stipulated that restarting or repeating the planning of the new reverse corridor section dedicated to the vehicle so as to drive out of the reverse track of the original plan. A secondary collision is, for example, a collision with other detected objects or with the same object but with other vehicles in the vehicle group or with a collision with another corresponding vehicle in the vehicle group. When the driving out plan from the reverse track of the original plan was at least once, this secondary collision just became important. Replanning is performed with instructions, that is, the track offset distance of the reverse track interval of the new planning point and the original planning is greater than the track offset distance in the first round, so as to avoid a secondary collision. Therefore, the new planning point is further moved in the direction of the sensor effective range boundary of the sensor system, but does not exceed this boundary at this time. This replanning may become necessary, for example, if, although according to the first planning, the trailer can be turned along the relevant new reversing corridor section without collision, the tractor must deviate further from the originally planned reversing trajectory for this purpose and thus collides with one of the detected objects. Alternatively or additionally, it can be provided that the replanning is carried out with the instruction that the exit point is closer to the vehicle group so that a smaller turning amplitude of the tractor is sufficient to drive the vehicle group around the relevant collision point.

[0019] In a possible extended design, the entry into the originally planned reverse trajectory is also planned. For this purpose, an entry point is determined on the originally planned reverse trajectory, which is located downstream of the problem point on the originally planned reverse trajectory with respect to the reverse direction. This means that if the vehicle group continues to travel along the reverse trajectory, it will first reach the problem point and then the entry point. In step S4, for example, another new reverse trajectory section is planned between the new planning point and the entry point by a reverse trajectory generation module, and thus another vehicle-specific new reverse corridor section is planned for each vehicle, so as to enter the originally planned reverse trajectory.

[0020] If it is determined when planning a new vehicle-specific reverse corridor section or a new reverse trajectory section in order to drive into the reverse trajectory originally planned that traveling along these new reverse corridor sections will cause additional / different secondary collisions, then it is stipulated in a possible extended design that the planning of the new vehicle-specific reverse corridor section is restarted or repeated in order to drive into the reverse trajectory originally planned. This additional / different secondary collision only becomes important when the entry into the reverse trajectory originally planned has been planned at least once. The replanning is performed with instructions, that is, a further entry point from the vehicle group is determined, so that the smaller steering amplitude of the tractor is sufficient to make the vehicle group travel around the relevant collision point. Alternatively or additionally, it is stipulated that the plan for driving out of the reverse trajectory originally planned is repeated as described above, and wherein the new planning point is moved further to the sensor effective range boundary of the sensor system. By planning the exit and entry, in this method, it is advantageous to deviate from the reverse trajectory originally planned only to a particularly small extent.

[0021] Another possible embodiment provides that before the driver assistance system or its vehicle control module intervenes for the first time in the lateral guidance of the towing vehicle, the exit from the originally planned reverse trajectory and the entry into the originally planned reverse trajectory are planned for the entire planned reverse trajectory. In other words, the planning scope extends to the end point of the planned reverse trajectory. This allows particularly safe and smooth assisted reverse travel.

[0022] According to an alternative to this design, as soon as the driver assistance system determines that a predetermined planned minimum distance has been reached between the current position of the vehicle group and the problem point, an exit from the originally planned reverse trajectory is planned. In this case, an entry into the originally planned reverse trajectory is planned when the vehicle group is located on a new reverse trajectory section. In this case, the planning scope only covers a partial route of the planned reverse trajectory, so that the computing power required in the method can be saved. The method can thus be carried out particularly efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features of the present invention can be derived from the following description of the drawings and from the drawings. The features and feature combinations mentioned above in the specification and the features and feature combinations shown below in the description of the drawings and / or in the drawings alone can be used not only in the respectively given combination, but also in other different combinations or alone, as long as it does not depart from the scope of the present invention.

[0024] To illustrate the method for assisted reverse driving with a vehicle combination, the following figures show:

[0025] Figure 1 A schematic top view showing a vehicle combination in forward motion;

[0026] Figure 2 A schematic top view of a simulated reverse vehicle combination is shown, wherein objects detected during forward travel are classified as collision objects at that time;

[0027] Figure 3 A schematic top view shows a vehicle combination at the start of reverse travel assisted by a driver assistance system, wherein an object obstructs collision-free reverse travel;

[0028] Figure 4 A schematic top view of a vehicle combination is shown, wherein an exit from an originally planned reverse trajectory is planned;

[0029] Figure 5 A schematic top view of a vehicle combination is shown, wherein an entry into an originally planned reverse trajectory is planned; and

[0030] Figure 6 A schematic top view of a vehicle combination is shown for which a collision-free reverse trajectory is planned. DETAILED DESCRIPTION

[0031] In the following, a method for assisted reverse driving with a vehicle combination 1 , a driver assistance system configured to carry out the method, and a motor vehicle having the driver assistance system are described together. In the figures, identical or functionally identical elements are provided with the same reference numerals.

[0032] The vehicle group 1 is a vehicle combination, which includes a tractor 2 and a trailer 3 connected to the tractor 2 via a trailer coupling. One of the vehicles 2, 3, in this case the tractor 2, is equipped with a driver assistance system, which is configured to perform the method. The tractor 2 is designed as a passenger car here.

[0033] In the method for assisted reverse travel with a vehicle combination 1, first the vehicle combination 1 is driven forward in step S1 of the method. Figure 1 , which shows a schematic top view of a vehicle group 1 in forward motion. A forward trajectory 4 of the vehicle group 1 representing forward motion is stored in a trajectory memory of the driver assistance system, which is designed as a ring memory. During the forward motion of the vehicle group 1, the forward trajectory 4a of the tractor 2 and the forward trajectory 4b of the trailer 3 hardly deviate from each other, so they are considered to be coincident. During the forward motion, a point cloud is acquired by the sensor system of the tractor 2, which detects an object 5 arranged beside the side of the forward trajectory 4. The point cloud acquired by the sensor system is stored in the object memory of the driver assistance system.

[0034] Figure 2A schematic top view of a simulated reverse vehicle group 1 is shown, wherein an object 5 detected during the forward movement is classified as a collision object 6 at that time. During the forward movement or after the forward movement is completed, in step S2, in this example, a reverse trajectory 7 for the vehicle group 1 and a corresponding vehicle-specific reverse corridor 8, 9 for vehicles 2, 3 are planned by a reverse trajectory generation module of the driver assistance system. Figure 3 ). The reverse trajectory 7 of the vehicle group 1 is planned in such a way that it deviates as little as possible from the forward trajectory 4 being traveled. Therefore, the forward trajectory 4 serves as a reference trajectory for the upcoming reverse movement. For each vehicle 2, 3, a vehicle-specific reverse corridor 8, 9 corresponding to the reverse trajectory 7 is individually planned. Therefore, a reverse corridor 8 is planned for the tractor 2 and a reverse corridor 9 is planned for the trailer 3. In step S3 of the method, the detected object 5 is currently classified by the object classification module of the driver assistance system. If the corresponding object is located in one or both of the planned reverse corridors 8, 9, the detected object 5 at that time is classified as a collision object 6. For this purpose, for example Figure 2 As shown, reverse travel is simulated along reverse travel trajectory 7 originally planned in step S2 .

[0035] Figure 3 1 shows a schematic top view of the vehicle group 1 at the beginning of reverse maneuvering assisted by the driver assistance system, wherein the collision object 6 initially blocks the collision-free reverse maneuvering of the vehicle group 1. As can be seen, the collision object 6 is located in the reverse corridor 9 of the trailer 3. In this case, step S4 of the method provides for generating a new reverse trajectory 7a (see FIG. 1 ) by means of a reverse trajectory generation module. Figure 6 ) and thus generate for each vehicle 2, 3 a respective vehicle-specific new reverse corridor 8a, 9a (see Figure 6 ). The respective vehicle-specific new reverse corridors 8a, 9a are generated so that they deviate as little as possible from the respective reverse corridors 8, 9 planned in step S2. However, the two new reverse corridors 8a, 9a are at least generated so that the collision object 6 is not located in any of the vehicle-specific new reverse corridors 8a, 9a.

[0036] Figure 4 A schematic top view of a train set 1 is shown, wherein an exit from the planned reverse trajectory 7 is planned, so that a first new reverse trajectory section 10 and thus first new vehicle-specific reverse corridor sections 11, 12 are planned (see Figure 6), in order to drive out of the reverse trajectory 7 of the original plan. For this purpose, a problem point 13 located on the reverse trajectory 7 originally planned in step S2 is determined, at which the reverse trajectory 7 and the outer contour point 6a of the collision object 6 are spaced a minimum distance apart from each other. Subsequently, a tangent 14 of the reverse trajectory 7 is determined, which branches in the problem point 13. Subsequently, a vertical line 15 relative to the tangent 14 that intersects the outer contour point 6a is established. Subsequently, a new planning point 16 is arranged in a straight extension of the vertical line 15 on the side of the reverse trajectory 7 opposite to the outer contour point 6a, wherein a trajectory offset distance is formed between the reverse trajectory 7 of the original plan and the new planning point. This trajectory offset distance is at least greater than zero, but is still selected so that it is as close as possible to the reverse trajectory 7 of the original plan. At least during the first planning of driving out, the trajectory offset distance is selected at most so long that it is classified as possible in a first-order approximation manner by the driver assistance system to pass the problem point 13 without collision with the vehicle group 1. In particular, the trajectory deviation distance is limited, more precisely, by the sensor effective range 17 of the sensor system of the tractor 2, which is approximately four meters in each case perpendicularly and transversely to the respective trajectory 4, 7, 7a traveled by the tractor 2. Subsequently, an exit point 18 is determined on the originally planned reverse trajectory 7, which is located upstream of the problem point 13 on the originally planned reverse trajectory 7 with respect to the reverse direction 19. In step S4, in this example, a first new reverse trajectory section 10 is planned between the exit point 18 and the new planning point 16 by the reverse trajectory generation module, and thus a vehicle-specific new reverse corridor section 11, 12 is planned for each vehicle 2, 3, so as to exit from the originally planned reverse trajectory 7.

[0037] If it is determined that driving along these new reverse corridor sections 10, 11 will lead to a secondary collision when planning new vehicle-specific reverse corridor sections 11, 12 or new reverse trajectory sections 10 in order to exit the originally planned reverse trajectory 7, it is provided to restart or repeat the planning of the new vehicle-specific reverse corridor sections 11, 12. The replanning is performed with an indication, that is, the trajectory offset distance between the new planning point 16 and the originally planned reverse trajectory 7 is greater than the trajectory offset distance in the first round, so as to avoid a secondary collision. Alternatively or additionally, the replanning is performed with an indication, that is, the exit point 18 is closer to the vehicle group 1.

[0038] In this example, entry into the originally planned reverse trajectory 7 is also planned. For this purpose, an entry point 20 is determined on the originally planned reverse trajectory 7, which is located downstream of the problem point 13 on the originally planned reverse trajectory 7 with respect to the reverse direction 19. In step S4, a second new reverse trajectory section 21 is planned between the new planning point 16 and the entry point 20 by the reverse trajectory generation module, and thus a vehicle-specific second new reverse corridor section 22, 23 is planned for each vehicle, so as to enter the originally planned reverse trajectory 7.

[0039] If it is determined during the planning of the second new vehicle-specific reverse corridor sections 22, 23 or the new reverse trajectory section 21 for entering the originally planned reverse trajectory 7 that driving along these new reverse corridor sections 22, 23 will lead to another / different secondary collision, it is provided to restart or repeat the planning of the second new vehicle-specific reverse corridor sections 22, 23. The replanning is performed with an indication, i.e., determining an entry point 20 that is further away from the vehicle group 1. Alternatively or in addition, the planning of the exit from the originally planned reverse trajectory 7 is repeated as described above, wherein the new planning point 16 is moved further to the edge of the sensor effective range 17.

[0040] Figure 6 A schematic top view of a vehicle combination 1 is shown, for which a new collision-free reversing trajectory 7a is planned / planned. Based on the new reversing trajectory 7a, the vehicle combination 1 is driven in reverse in a reversing assistance operating mode by means of a vehicle control module of a driver assistance system, wherein the vehicle control module of the driver assistance system at least intervenes in the transverse guidance of the tractor 2 in such a way that the vehicle combination 1 travels along the new reversing trajectory 7a with the new reversing trajectory sections 10, 21 and thus travels through the vehicle-specific new reversing corridors 8a, 9a with the new reversing corridor sections 11, 12, 22, 23. In the present example, during the reversing travel, the driver assistance system travels along the entire new reversing trajectory 7a at once, i.e. without forward correction actions, and thus travels through the vehicle-specific new reversing corridors 8a, 9a. Furthermore, in step S5, the driver assistance system completely takes over the transverse guidance of the tractor 2 and / or the longitudinal guidance of the tractor 2.

[0041] Before the driver assistance system or its vehicle control module intervenes for the first time in the transverse guidance of the tractor 2, the exit from the originally planned reverse trajectory 7 and the entry into the originally planned reverse trajectory 7 can be pre-planned for the entire originally planned reverse trajectory 7. Alternatively, the exit from the originally planned reverse trajectory 7 is planned as soon as the driver assistance system determines that a predetermined planned minimum distance has been reached between the current position of the vehicle group 1 and the problem point 13. In this case, the entry into the originally planned reverse trajectory 7 is planned when the vehicle group 1 is located on the first new reverse trajectory section 10.

[0042] Reference again Figure 1 and Figure 2 It is explained that according to the example described here, for each vehicle 2, 3, the driver assistance system is predefined with a first imaginary collision rectangle 24, which completely surrounds the respective vehicle 2, 3 and moves together with the vehicle 2, 3. In the present example, the collision rectangle 24 is predefined in such a way that the outer contour of the relevant vehicle 2, 3 and the edge of the collision rectangle 24 are spaced apart by a first safety distance of 25 cm. In addition, for each vehicle 2, 3, the driver assistance system is predefined with an imaginary circumscribed circle 25, on which the corner points of the relevant collision rectangle 24 are always located. In the present example, it is also provided that if the respective object 5 intersects one or both circumscribed circles 25 during forward travel, the detected object 5 is respectively classified as a critical object. In step S3 of the method, only those detected objects 5 that would intersect the collision rectangle 24 during reverse travel assisted by the driver assistance system are classified as collision objects 6 at that time, if necessary.

[0043] Optionally, a second imaginary collision rectangle completely located within the first collision rectangle 24 and a third imaginary collision rectangle completely located within the second collision rectangle are pre-given to each vehicle 2, 3. In this case, the edge of the first collision rectangle 24 and the outer contour of the relevant vehicle are spaced apart from each other by a first safety distance of 75 cm. The edge of the second collision rectangle and the edge of the first collision rectangle 24 are spaced apart from each other by, for example, 25 cm, so that the edge of the second collision rectangle and the outer contour of the relevant vehicle 2, 3 are spaced apart from each other by a second safety distance of 50 cm. In addition, the edge of the third collision rectangle and the edge of the second collision rectangle are spaced apart from each other by, for example, 25 cm, so that the edge of the third collision rectangle and the outer contour of the relevant vehicle 2, 3 are spaced apart from each other by a third safety distance of 25 cm. In this case, in reverse driving assisted by the driver assistance system, as long as the corresponding collision object 6 intersects with the first collision rectangle 24 but does not intersect with the second collision rectangle or the third collision rectangle, the collision object 6 at that time is classified as a prompt object. A prompt operation is performed by the driver assistance system in response to the prompt object. For example, the driver is informed that the vehicle group 1 is approaching the collision object 6 and / or the driving speed of the vehicle group 1 is reduced and / or the driver is proposed to fully or partially take over the control of the vehicle group 1. Furthermore, during the assisted reverse driving, as long as the corresponding collision object 6 intersects the first collision rectangle 24 and the second collision rectangle but does not intersect the third collision rectangle, the collision object 6 at that time is classified as a warning object, wherein a warning operation is performed by the driver assistance system as a response to the warning object. For example, the driver is informed that the vehicle group 1 is facing a collision and / or the driving speed of the vehicle group 1 is further reduced / reduced, and / or the driver is advised to completely take over the control of the vehicle group 1 with greater urgency. If the collision object 6 enters the innermost collision rectangle, that is, the third collision rectangle, a collision emergency operation can be performed. For example, the driver is informed that a collision is about to occur and / or the vehicle group 1 is completely stopped and / or the control of the vehicle group 1 is completely handed over to the driver again.

[0044] Reference numerals list

[0045] 1 car group

[0046] 2 Tractor

[0047] 3 Trailer

[0048] 4. The forward trajectory of the vehicle group

[0049] 4a The forward trajectory of the tractor

[0050] 4b Trailer's forward trajectory

[0051] 5 Objects

[0052] 6 Collision Objects

[0053] 6a Outer contour point

[0054] 7 The reverse trajectory of the train group

[0055] 7a New reverse trajectory

[0056] 8 Reverse corridor for tractors

[0057] 8a New reverse corridor for tractors

[0058] 9 Trailer reverse corridor

[0059] 9a New reverse corridor for trailers

[0060] 10 First new reverse trajectory segment

[0061] 11 The first new reverse corridor section for tractors

[0062] 12 First new reverse corridor section for trailers

[0063] 13 Problems

[0064] 14 Tangent

[0065] 15 Vertical Line

[0066] 16 New planning points

[0067] 17 Sensor effective range

[0068] 18 Exit Point

[0069] 19 Reverse direction

[0070] 20 Entry Point

[0071] 21 Second new reverse trajectory section

[0072] 22 The second new reverse corridor section for tractors

[0073] 23 The second new reverse corridor section for trailers

[0074] 24 First collision rectangle

[0075] 25 Circumcircle

[0076] S1–S5 Method Steps

Claims

1. A method for assisted reverse driving with a vehicle combination (1), the vehicle combination having a tractor (2) and a coupled trailer (3) and a driver assistance system, wherein: S1 first moves forward with vehicle group (1), wherein: - storing the corresponding forward trajectory (4) in the driver assistance system, - detecting an object (5) arranged laterally to the front track (4) by means of a sensor system of the tractor (2), S2 Planning: a reverse trajectory (7) which deviates as little as possible from the forward trajectory (4) being travelled, - planning a vehicle-specific reverse corridor (8, 9) corresponding to the planned reverse trajectory (7) for each vehicle (2, 3) in the vehicle group (1), S3: if the corresponding object (5) is located in one or both of the planned reverse corridors (8, 9), the detected object (5) is classified as a collision object (6); S4: when one or more detected objects (5) are classified as collision objects (6) at that time, a new reverse trajectory (7a) is generated and thus a new vehicle-specific reverse corridor (8a, 9a) is generated for each vehicle (2, 3), the new reverse corridor deviating as little as possible from the respective planned reverse corridor (8, 9), so that the collision object (6) is not located in any vehicle-specific new reverse corridor (8a, 9a) at this time. S5 The vehicle group (1) drives in reverse with the aid of a driver assistance system, wherein the driver assistance system intervenes in the lateral guidance of the tractor (2) at least in such a way that the vehicle group (1) drives along a new reverse trajectory (7a) and thus drives through a new vehicle-specific reverse corridor (8a, 9a).

2. The method according to claim 1, It is characterized in that During reverse travel, the entire new reverse trajectory (7a) is traveled at once and thus a new vehicle-specific reverse corridor (8a, 9a) is traveled.

3. The method according to claim 1 or 2, It is characterized in that In step S5, the driver assistance system completely takes over the transverse guidance of the tractor (2) and / or the longitudinal guidance of the tractor (2).

4. The method according to any one of the preceding claims, It is characterized in that - for each vehicle (2, 3) in the vehicle group (1), the driver assistance system is given a virtual collision rectangle (24) which completely surrounds the respective vehicle (2, 3) and moves together with the vehicle (2, 3), - for each vehicle (2, 3) in the train group (1), the driver assistance system is given an imaginary circumscribed circle (25), on which the corner points of the associated collision rectangle (24) always lie, - if one or both circumscribed circles (25) intersect the corresponding object (5) during forward travel, the detected object (5) is respectively classified as a critical object, In step S3, only critical objects among the detected objects (5) are classified as collision objects (6) at that time, if necessary, if the corresponding objects (5) intersect the collision rectangle (24) during reverse driving assisted by the driver assistance system.

5. The method according to claim 4, It is characterized in that For each vehicle (2, 3), a hypothetical second collision rectangle completely located within the first collision rectangle (24) and a hypothetical third collision rectangle completely located within the second collision rectangle are predefined, wherein during reverse driving assisted by a driver assistance system, the collision object (6) at that time is - is classified as a warning object if the corresponding collision object (6) intersects the first collision rectangle (24) but does not intersect the second collision rectangle or the third collision rectangle, wherein a warning operation is performed by the driver assistance system in response to the warning object, - is classified as a warning object if the respective collision object (6) intersects the first collision rectangle (24) and the second collision rectangle but not the third collision rectangle, wherein a warning operation is executed by the driver assistance system as a response to the warning object.

6. The method according to any one of the preceding claims, It is characterized in that An exit from an originally planned reverse trajectory (7) is planned by setting up a perpendicular line (15) relative to a tangent line (14) of the reverse trajectory (7) intersecting an outer contour point (6a) at a problem point (13) of the originally planned reverse trajectory (7) in step S2, wherein the reverse trajectory (7) and an outer contour point (6a) of the collision object (6) are spaced at a minimum distance from each other at the problem point, - arranging a new planned point (16) on the side of the reverse trajectory (7) opposite to the outer contour point (6a) and on a straight extension line of the vertical line (15), wherein a trajectory offset distance is formed between the originally planned reverse trajectory (7) and the new planned point (16), - determining an exit point (18) on the originally planned reverse trajectory (7), wherein the exit point is located upstream of the problem point (13) on the originally planned reverse trajectory (7) with respect to the reverse direction (19), - In step S4, a new reverse trajectory section (10) is planned between the exit point (18) and the new planning point (16) and thus a vehicle-specific new reverse corridor section (11, 12) is planned for each vehicle (2, 3) in order to exit the originally planned reverse trajectory (7).

7. The method according to claim 6, It is characterized in that Planning entry into the originally planned reverse trajectory (7) by determining an entry point (20) on the originally planned reverse trajectory (7), the entry point being located downstream of a problem point (13) on the originally planned reverse trajectory (7) with respect to the reverse direction (19), In step S4, a further new reverse trajectory section (21) is planned between the new planning point (16) and the entry point (18), and thus a vehicle-specific further new reverse corridor section (22, 23) is planned for each vehicle (2, 3) in order to enter the originally planned reverse trajectory (7).

8. The method according to claim 6 or 7, It is characterized in that - planning, for the entire planned reversing trajectory (7), a departure from the originally planned reversing trajectory (7) and a return to the originally planned reversing trajectory (7) before the driver assistance system intervenes for the first time in the lateral guidance of the tractor (2), or - As soon as the driver assistance system determines that a predetermined planned minimum distance has been reached between the current position of the vehicle group (1) and the problem point (13), an exit from the originally planned reverse trajectory (7) is planned, and when the vehicle group (1) is located on a new reverse trajectory section (10), an entry into the originally planned reverse trajectory (7) is planned. 9 . A driver assistance system configured to carry out a method designed according to one of the preceding claims.

10. A motor vehicle having a driver assistance system according to claim 9, wherein: The motor vehicle is designed to function as a tractor (2) for a vehicle group (1).

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