Procedure and system for controlling a motor vehicle

Abstract

Method for steering a motor vehicle (10) traveling on a road (12) in an instantaneous lane (14), wherein the road (12) has at least one further lane (16) adjacent to the instantaneous lane (14) of the motor vehicle (10), comprising the following steps: - Determining free areas (Bf) and / or occupied areas (Bb) occupied by other road users (18, 20), at least in the instantaneous lane (14) of the motor vehicle (10) and in the at least one further lane (14), wherein the free areas (Bf) and the occupied areas (Bb) are spatial-temporal areas;- Determining lane-change zones where a lane change between the two lanes (14, 16) is possible, and / or lane-keeping zones where a lane change between the two lanes (14, 16) is not possible, based on the determined free zones (Bf) and / or occupied zones (Bb), wherein the lane-change zones and the lane-keeping zones are each a spatiotemporal sub-zone (Ti) of the free zones (Bf); and - Determining possible driving maneuvers of the motor vehicle (10) at least between pairwise adjacent lane-change zones and / or lane-keeping zones; characterized in that a lane vertex (Vi) is assigned to each of the lane-change zones and / or the lane-keeping zones of the two lanes, wherein the lane vertices (Vi) are connected pairwise by edges if a driving maneuver of the motor vehicle (10) is possible between the corresponding lane-change zones and / or the lane-keeping zones.

Description

The invention relates to a method for controlling a motor vehicle, a control unit for a system for controlling a motor vehicle, a system for controlling a motor vehicle, a computer program for carrying out the method, and a computer-readable data carrier containing such a computer program. One of the main challenges for driver assistance systems that partially automate the longitudinal and lateral movement of a motor vehicle, and especially for fully automated vehicles, is to analyze a specific situation in which the vehicle is located and to derive appropriate, meaningful driving maneuvers for the vehicle based on this. The complexity of calculating driving maneuvers generally increases with the duration of each maneuver. If various possible driving maneuvers need to be determined for a longer period, for example, longer than three seconds, or if the maneuvers are complex and involve multiple lane changes, then existing methods are no longer able to determine them in real time. DE 10 2015 016 899 A1 discloses a method according to the preamble of claim 1. German patent DE 10 2011 080 928 A1 discloses a method for assisting a driver. During a planned lane change, the system determines whether an object is located next to the vehicle in an area not visible to the driver. Once detected, the object is tracked to determine whether it leaves or enters the lane adjacent to the vehicle. A warning is also issued if the object is in the adjacent lane. The object of the invention is therefore to provide a method and a system for controlling a motor vehicle in which the disadvantages of the prior art are improved. The problem is solved according to the invention by a method for controlling a motor vehicle according to claim 1. The method according to the invention is based on the fundamental idea of ​​mapping the road onto a space-time diagram and dividing the road in this space-time diagram into different sub-areas, namely sub-areas where a lane change is possible and sub-areas where a lane change is not possible. Between these individual sub-areas, possible driving maneuvers can then be determined very quickly and efficiently, since only a small sub-area of ​​the road needs to be considered at any given time, and not the entire traffic situation. Therefore, the method according to the invention makes it possible to determine various possible driving maneuvers in real time. In particular, the method according to the invention is a computer-implemented method that is executed on a control unit of the motor vehicle and / or on a control unit of a higher-level control system, which is assigned, for example, at least to the section of the road in which the motor vehicle is currently driving, wherein the motor vehicle and the control system are in signal-transmitting communication with each other and can exchange signals with each other. The spatiotemporal domains and their subdomains are each described by at least one spatial coordinate, in particular a longitudinal coordinate in the direction of the road, and by a temporal coordinate. Specifically, a coordinate in the transverse direction to the road is discretized and is fixed to a specific value for each lane. A driving maneuver, as used here and in the following, is understood to mean at least one transition of the motor vehicle from one spatial-temporal sub-region to another. These transitions can, of course, only occur in the positive direction of time. Generally, a driving maneuver consists of several successive transitions between individual, adjacent spatial-temporal sub-regions. In particular, the occupied areas include not only those sections actually occupied by another road user, but also a required safety distance from that other road user, whereby the safety distance may be predetermined, preset, and / or selectable by the driver. Additionally, the occupied areas may also include sections that are inaccessible due to other obstacles, such as construction sites or similar. According to the invention, a lane vertex is assigned to each of the lane-change zones and / or lane-keeping zones of the two lanes. The lane vertices are connected pairwise by edges when a driving maneuver of the motor vehicle is possible between the corresponding lane-change zones and / or lane-keeping zones, and in particular, the lane vertices are time-ordered. A sequence of successively executable driving maneuvers is therefore obtained by an interrupted line of edges along the lane vertices in ascending time. In this way, a graph is generated that contains several different possible driving maneuvers, in particular all possible driving maneuvers. The generated graph can then be further processed by other modules and / or subsystems of the motor vehicle, for example, by a module that determines the driving maneuver to be executed from among the possible maneuvers. One aspect of the invention provides that the lane-changing zones are those portions of the free areas of the current lane and the at least one further lane in which both the current lane and the at least one further lane are free of other road users. In particular, the free areas are also free of other obstacles, such as construction sites or similar, that would prevent driving. The lane-changing zones are therefore those areas of the current lane and the at least one further lane in which a lane change is possible because both the current lane and the at least one further lane are free. According to one embodiment of the invention, the lane-keeping zones are those sub-areas of the free areas of the current lane and the at least one further lane in which the other lane is occupied and / or a lane change is otherwise not possible. In other words, the lane-keeping zones are those sub-areas in which a lane change is not possible because another road user is in the adjacent lane, because the adjacent lane is otherwise blocked, and / or because there is a no-overtaking or no-lane-changing rule on the corresponding section of road. According to a further aspect of the invention, the lane-change zones are determined by assessing whether a lane-change zone, spatially located between the current lane and at least one other lane, is clear, occupied by other road users, or otherwise impassable. A transition from one lane to another thus occurs via this lane-change zone. The lane-change zone is clear precisely when both the current lane and the other lane are clear. Consequently, the lane-change zone is occupied precisely when at least one of the two lanes is occupied. The lane-change zone takes into account the fact that the motor vehicle and other road users briefly block both lanes during a lane change.The lane change zone is otherwise impassable, for example, if there is a no-overtaking zone or a no-lane-change zone on the relevant section of road and / or if obstacles prevent driving in the lane change zone. Preferably, at least one space-time polygon corresponding to the current lane, at least one corresponding to at least one other lane, and at least one corresponding to the occupied areas are determined. From these determined polygons, space-time polygons corresponding to the free areas of the two lanes are calculated using polygon clipping. In particular, the polygons corresponding to the occupied areas are removed from the polygons corresponding to one of the two lanes to determine the free areas. The determination of the free areas is thus reduced to a geometric operation that can be performed very quickly and efficiently, thereby saving computational time when determining possible driving maneuvers. In particular, each lane and the occupied areas of each lane are polygons in an (L,t) coordinate system, where L is the instantaneous longitudinal direction of the road and t is time. The free areas for lane i are thus, symbolically expressed, obtained by the operation PSpur,i\Pbesetzt,i, where PSpur,ida is the space-time polygon corresponding to lane i and Pbesetzt,iale comprises space-time polygons that enclose occupied areas in lane i. Preferably, an intersection of the two polygons corresponding to the free areas in the two lanes is formed to determine the lane change zones and lane keeping zones, in particular to determine whether the lane change zone is clear. In other words, the free areas of the lane change zone are obtained as the intersection of the polygons corresponding to the free areas in the individual lanes, i.e., by the operation Pfree,i ∩ Pfree,j. The determination of the lane change zones and lane keeping zones is thus reduced to a geometric operation that can be performed very quickly and efficiently, thereby saving computational time when determining possible driving maneuvers. One embodiment of the invention provides that at least the current lane and / or at least one other lane are transformed into a Frenet-Serret coordinate system. In this coordinate system, every road is curvature-free, so that every traffic situation can be treated in the same way, regardless of the actual road alignment. In particular, the space-time polygons described above are determined in the Frenet-Serret coordinate system. Preferably, at least one lane-change zone vertex is assigned to the lane-change zone, in particular, the lane-change zone is divided into several time strips, each of which is assigned at least one lane-change zone vertex, wherein the at least one lane-change zone vertex is connected pairwise to the lane vertices by edges if a driving maneuver of the motor vehicle is possible between the corresponding sub-area of ​​the lane-change zone and the corresponding lane-change area or lane-keeping area. A sequence of successively executable driving maneuvers is therefore obtained by an interrupted line of edges along the lane vertices and the lane-change zone vertices in ascending time direction. In this way, a graph is generated that contains several different possible driving maneuvers, in particular all possible driving maneuvers.The generated graph can then be further processed by other modules and / or subsystems of the vehicle, for example by a module that determines which driving maneuver to execute from the possible driving maneuvers. In particular, a new time slot for the lane change zone begins with each event on either of the two lanes. An event, as defined here and in the following, is any kind of change in the occupancy of either of the two lanes. Preferably, several different driving maneuvers for the motor vehicle are determined, in particular all possible driving maneuvers. Thus, not just a single possible driving maneuver is determined, but several different ones, where the different driving maneuvers represent the various ways in which the motor vehicle can be controlled. The different driving maneuvers can then be forwarded to further modules and / or subsystems of the motor vehicle, for example, to a module that selects the driving maneuver to be executed from among the possible ones. Another aspect of the invention provides that, when determining the free areas and / or areas occupied by other road users, predicted trajectories of those other road users are taken into account. These predicted trajectories can be generated by another module or subsystem of the vehicle, obtained from other road users via inter-vehicle communication, and / or obtained from a guidance system that is at least assigned to the section of the road in which the vehicle is currently traveling. In particular, the predicted trajectories also include lane changes by other road users. The method according to the invention thus makes it possible to incorporate the driving maneuvers of other road users into the determination of the possible driving maneuvers of the vehicle and to control the vehicle in a manner adapted to the respective specific road traffic situation. According to one embodiment of the invention, it is determined whether the motor vehicle can reach the respective spatial-temporal sub-ranges, in particular taking into account the current speed of the motor vehicle, its maximum deceleration, its maximum acceleration, and / or a speed limit. The sub-ranges that cannot be reached are then no longer considered in the subsequent steps for controlling the motor vehicle, thereby saving computational time when determining the possible driving maneuvers. Preferably, corresponding trajectories of the vehicle are determined for the driving maneuvers. Each trajectory is a determined space-time curve along which the vehicle moves when the trajectory is selected and the vehicle is controlled accordingly. In particular, these are optimized trajectories, which are optimized based on one or more conditions. For example, the distance traveled should be as short as possible, the duration of the driving maneuver should be minimized, and / or any longitudinal and / or lateral accelerations should not exceed a predefined limit. In particular, at least one sensor detects the current lane and / or at least one other lane in order to determine the free areas, occupied areas and / or areas where traffic is unsafe. The at least one sensor generates corresponding environmental data, which is used to create a representation of the environment, in particular in the form of a space-time diagram. The at least one sensor can be a camera, a radar sensor, a distance sensor, a LIDAR sensor and / or any other type of sensor suitable for detecting at least part of the vehicle's surroundings. Alternatively or additionally, at least one sensor can be configured as an interface to a guidance system that is assigned to at least the section of road in which the vehicle is currently traveling. The guidance system is configured to transmit environmental data about the road and / or other road users, in particular their predicted trajectories, to the vehicle and / or other road users. According to a further embodiment of the invention, at least one of the possible driving maneuvers is selected, and the driver is given instructions based on this at least one maneuver. These instructions consist, in particular, of information about the at least one selected driving maneuver. For example, several possible driving maneuvers are selected and displayed on a user interface. The driver can then decide which of the possible driving maneuvers should be executed and select this maneuver, for example, via the user interface. Preferably, one of the possible driving maneuvers is selected, and the vehicle is controlled accordingly. The vehicle is then controlled at least partially automatically, and in particular fully automatically, based on the selected driving maneuver. Preferably, the selected driving maneuver is an optimal maneuver chosen from among several possible maneuvers based on boundary conditions. For example, the distance traveled should be as short as possible, the duration of the driving maneuver should be minimized, and / or any longitudinal and / or lateral accelerations should not exceed a predefined limit. The problem is also solved according to the invention by a control unit for a system for controlling a motor vehicle, wherein the control unit is configured to carry out a method described above. Regarding the advantages, reference is made to the above explanations concerning the method. The control unit can be part of the motor vehicle or part of a higher-level system, for example, part of the control system. The problem is further solved according to the invention by a system for controlling a motor vehicle, with a control unit described above. Regarding the advantages, please refer to the above explanations concerning the procedure. The problem is also solved according to the invention by a computer program with program code means to carry out the steps of a method described above when the computer program is executed on a computer or a corresponding computing unit, in particular a computing unit of a control device described above. Regarding the advantages, reference is made to the above explanations concerning the method. In the following, "program code means" refers to computer-executable instructions in the form of program code and / or program code modules in compiled and / or uncompiled form, which may be in any programming language and / or machine language. The problem is further solved according to the invention by a computer-readable data carrier on which a computer program as described above is stored. The data carrier can be an integral part of the control unit described above or can be designed separately from the control unit. The data carrier has a memory in which the computer program is stored. The memory is any suitable type of memory, for example, based on magnetic and / or optical data storage. Further advantages and features of the invention will become apparent from the following description and the accompanying drawings, to which reference is made. These show: - Fig. 1 schematically a road traffic situation; - Fig. 2 a schematic block diagram of a system according to the invention for controlling a motor vehicle; - Fig. 3 a flowchart of the steps of a method according to the invention; - Figs. 4(a) and 4(b) schematically a road before transformation into a Frenet-Serret coordinate system and the road after transformation into a Frenet-Serret coordinate system, respectively; and - Figs. 5, 6, 7, 8, 9 to 10 each illustrate individual steps of the method according to the invention shown in Fig. 3. Figure 1 schematically shows a road traffic situation in which a motor vehicle 10 is driving on a road 12 in a current lane 14. Next to the current lane 14 runs another lane 16. On road 12, there is also a first additional road user 18 and a second additional road user 20, currently in lane 14 and in the next lane 16, respectively. In the example shown, the additional road users 18 and 20 are passenger cars, but they could also be trucks, motorcycles, or any other type of road user. Between the current lane 14 and the next lane 16 lies a lane change zone 21, which partially overlaps with the current lane 14 and the next lane 16. The dashed lines 22 and 24 indicate that the first other road user, 18, plans to change from the current lane 14 via the lane change zone 21 to the next lane 16 in the near future, and that the second other road user, 20, plans to change from the next lane 16 via the lane change zone to the current lane 14 of vehicle 10 in the near future. This is indicated by the other road users 18 and 20, for example, by using the appropriate turn signal. Furthermore, Fig. 1 shows a coordinate system with a longitudinal axis and a normal axis, where the longitudinal axis defines a longitudinal direction L and the normal axis defines a transverse direction N. The origin of the coordinate system lies in the longitudinal direction L at the current position of the front of the motor vehicle 10 and, viewed in the longitudinal direction L, at the right edge of the road. This particular coordinate system, which will also be used below, is a road-fixed coordinate system, meaning it does not move with the vehicle 10. Of course, any other coordinate system can also be used. As shown in Fig. 2, the motor vehicle 10 has a system 26 for controlling the motor vehicle 10. The system 26 comprises several sensors 28 and at least one control unit 30. The sensors 28 are arranged at the front, rear, and / or sides of the vehicle 10 and are designed to detect the vehicle 10's surroundings, generate corresponding environmental data, and transmit this data to the control unit 30. More precisely, the sensors 28 detect information at least about the current lane 14, the next lane 16, and other road users 18 and 20. The sensors 28 are each a camera, a radar sensor, a distance sensor, a LIDAR sensor and / or any other type of sensor suitable for detecting the environment of the motor vehicle 10. Alternatively or additionally, at least one of the sensors 28 can be configured as an interface to a control system that is assigned to at least the section of road 12 shown and is configured to transmit environmental data about road 12 and / or about other road users to the motor vehicle 10 and / or to other road users 18, 20. In this case, one of the sensors 28 can be configured as a mobile communication module, for example for communication according to the 5G standard. In general terms, the control unit 30 processes the environmental data received from the sensors 28 and controls the motor vehicle 10 based on this processed environmental data, at least partially automatically, and in particular fully automatically. Thus, a driver assistance system is implemented on the control unit 30 that can control the lateral and / or longitudinal movement of the motor vehicle 10 at least partially automatically, and in particular fully automatically. For this purpose, the control unit 30 is configured to carry out the process steps described below with reference to Figures 4, 5, 6, 7, 8, 9 to 10. More precisely, the control unit 30 comprises a data carrier 32 and a processing unit 34, wherein a computer program is stored on the data carrier 32, which is executed on the processing unit 34 and includes the program code means to carry out the steps of the process described below. First, the road 12, more precisely an image of the current lane 14 and the further lane 16 based on the environmental data obtained from the sensors 28, is transformed into a Frenet-Serret coordinate system (step S1). Step S1 is illustrated in Fig. 4. Fig. 4(a) shows the road 12 as it actually runs. In the example shown, the road, viewed in the longitudinal direction L, has a curvature to the left. Through a local coordinate transformation, the road 12 is transformed into the Frenet-Serret coordinate system, in which the road 12 no longer has a curvature, the result of which is shown in Fig. 4(b). As can be clearly seen, in this coordinate system the road 12 runs straight and without curvature along the longitudinal direction L. Next, free areas B and occupied areas B are determined in the current lane 14 and in the further lane 16 (step S2), whereby the free areas B and occupied areas B are each spatial-temporal areas. The free areas Bf are those spatial and temporal areas that are free from other road users 18, 20 and other obstacles that prevent driving on the respective lane 14, 16. The occupied areas Bb, on the other hand, are those spatial and temporal areas that are occupied by other road users 18, 20 and / or by other obstacles, such that the occupied areas Bb cannot be entered by the motor vehicle 10. In particular, the occupied areas Bb not only include areas that are actually occupied, but also encompass a safety distance that must be maintained, which may be specified, preset or selectable by the driver. To determine the occupied areas, the control unit 30 requires predicted trajectories 22, 24 of the other road users 18, 20. The control unit 30 can determine the trajectories 22, 24 itself, for example, based on environmental data received from the sensors 28, such as information that a turn signal of another road user 18, 20 is activated, or based on data exchanged via inter-vehicle communication. Alternatively, the control unit 30 can receive the trajectories 22, 24 directly from the other road users 18, 20 or from the guidance system. As shown in Fig. 5 using the specific example of Fig. 1, the free areas B and the occupied areas Bb are first determined for the current lane 14 and for the next lane 16, each in a tL diagram, where t is time. In this example, the first additional road user 18 initiates a lane change maneuver from its current lane 14 to the next lane 16 at time t = 1s, which is completed at time t = 5s. In the diagrams shown in Fig. 5, the first additional road user 18 occupies the upper of the two occupied areas Bb in each case. During the lane change, the first additional road user 18 occupies both lanes 14 and 16, at least temporarily. The second road user 20 initiates a lane change maneuver from the other lane 16 to the current lane 14 at time t = 3s, which is completed at time t = 7s. In the diagrams shown in Fig. 5, the second road user 20 occupies the lower of the two occupied areas Bb in each case. The slope of the occupied areas B corresponds to the speed of the respective other road user 18 or 20. In the example shown in Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9 to Fig. 10, the speed of the other road users 18, 20 is therefore constant. For simplification, the coordinate in the transverse direction N is discretized; it can therefore only assume the three different values ​​corresponding to the current lane 14, the next lane 16, and the lane change zone 21. The three diagrams shown in Fig. 5 are thus each a tL diagram for the current lane 14, for the next lane 16, and for the lane change zone 21. The hatched sections in the diagrams correspond to the occupied areas Bb of the respective lanes 14 and 16. The unhatched sections in the diagrams, on the other hand, correspond to the free areas Bf of the respective lanes 14 and 16. To determine the free areas Bf, a space-time polygon P14 or P16 is first determined for each lane 14, 16, which corresponds to the entire lane 14 or 16 in front of the vehicle 10, in particular the portion of lanes 14, 16 that lies within the range of the sensors 28. In Fig. 5, the polygons P14 and P16 are the quadrilaterals indicated by the dashed lines. Furthermore, space-time polygons P14,bb and P16, respectively, are transmitted for the two lanes 14 and 16, which enclose the occupied areas Bb of the respective lanes 14 and 16. The free areas Bfin of the current lane 14, or more precisely a polygon P14,f corresponding to the free areas Bfent, are then determined by polygon clipping, by removing the polygons P14,baus from the polygon P14ent. In other words, this is the operation Similarly, the free areas Bfin of the further lane 16 are determined by polygon clipping, by removing the polygons P16,baus from the polygon P16. Thus, the operation P16,f = P16\P16,b is performed. Next, as illustrated in Fig. 6, the free sections of the lane change zone 21 are determined (step S3). The lane change zone 21 is free if and only if both the current lane 14 and the next lane 16 are free and if the lane change zone 21 is not impassable for other reasons, such as obstacles or a no-overtaking zone. Therefore, the free sub-areas of lane change zone 21, or more precisely a polygon P21,f corresponding to the free sub-areas of lane change zone 21, are determined as the intersection of the two polygons P14, and P16,fer. If lane change zone 21 is impassable due to an obstacle or other reason, a corresponding space-time polygon Ph, which encloses the impassable sub-area of ​​lane change zone 21, is determined and removed from the aforementioned intersection. In other words, the free sub-areas P21,f of lane change zone 21 result from the operation The diagrams for the current lane 14 and for the next lane 16 are now each divided into time strips (step S4), with a new time strip beginning with each event. In Fig. 7, the different time strips are separated from each other by vertical dividing lines E, which are inserted into the diagram at each event. An event, as defined here and in the following, refers to any kind of change in the occupancy of the respective lane 14 or 16. Therefore, if an occupancy of any part of the current lane 14 or the further lane 16 begins or ends at a specific time, a new time strip begins in the diagram for the current lane 14 or for the further lane 16 at that time. The dividing lines E between the individual time strips in the diagrams for both lanes 14, 16 are also transferred to the diagram for the lane change zone 21. To achieve a consistent division of the diagrams across the three diagrams for the current lane 14, the next lane 16, and the lane change zone 21, diagonal dividing lines T are inserted in the diagrams for the current lane 14 and the next lane 16, each representing an extension of one of the occupied areas Bb. These additional diagonal dividing lines T are shown in Figures 8, 9 to 10. The vertical dividing lines E, the slanted dividing lines T and the occupied areas B divide each of the three diagrams into several sub-areas Tiein, where i is a natural number greater than zero, which can take values ​​from 1 up to a total number of sub-areas Tian. As shown in Fig. 8, each of the sub-areas of the Tider diagrams for the current lane 14 and for the next lane 16 is assigned a lane vertex Vi, while each sub-area of ​​the Tider diagrams for the lane change zone 21 is assigned a change zone vertex Wi (step S5). Here, i is again a natural number greater than zero, which can take values ​​from 1 up to a total number of sub-areas T. In Fig. 8, the track vertices Vi and the transition zone vertices Wi are each ordered internally within the diagram in terms of time, i.e., those vertices that correspond to sub-areas with shorter times are further to the left than those vertices that are assigned to sub-areas with longer times. Next, the lane vertices Vider of the current lane 14 are connected in pairs by edges (step S6), more precisely by directed edges, if a driving maneuver of the motor vehicle 10 is possible between the sub-areas Ti to which the lane vertices Vi are assigned. A driving maneuver is defined as "possible" if and only if the two sub-areas Ti directly border each other, i.e., are not separated by an occupied area Bb. Furthermore, a driving maneuver is naturally only possible in the positive time direction. The same procedure is repeated for the lane vertices Vider further lane 16 and for the change zone vertices Wider lane change zone 21. It should be noted that in Figures 9 and 10, the letters "T", "V", and "W" have been omitted for clarity. Instead, the sub-areas and vertices have simply been labeled with their corresponding numbers. Therefore, in Figures 9 and 10, numbers are not reference symbols but represent the index of the corresponding sub-area or vertex. The result of step S6 is shown in Fig. 9. The graph obtained in step S6 already contains all possible driving maneuvers for the motor vehicle 10 within the two lanes 14, 16 and within the lane-change zone 21. Next, those lane vertices Vider current lane 14 are connected to those lane change zone vertices Wi via directed edges whose associated sub-areas Tider current lane 14 and lane change zone 21 overlap (step S7). In other words, those lane vertices Vi are connected to those lane change zone vertices Wi whose associated sub-areas have a non-empty intersection when the two diagrams for current lane 14 and lane change zone 21 are superimposed. Furthermore, those lane change zone vertices Wi are connected via directed edges to those lane vertices Vi of the further lane 16 whose assigned sub-areas Tider lane change zone 21 and the further lane 16 overlap. Thus, those lane vertices Vi are connected to those lane change zone vertices Wi whose assigned sub-areas Tider have a non-empty intersection when the two diagrams for the further lane 16 and for the lane change zone 21 are superimposed. In other words, in step S7 the individual sub-areas are divided into free areas (Tider, Bfin, changeover areas, in which a lane change between the two lanes 14, 16 is possible) and lane keeping areas, in which a lane change between the two lanes 14, 16 is not possible. The result of step S7 is shown in Fig. 10. The graph obtained in step S7 contains all possible driving maneuvers for the vehicle 10 that involve a change from the current lane 14 to the next lane 16. Each of the possible driving maneuvers corresponds to a continuous traverse of edges in the graph shown in Fig. 10. The various possible driving maneuvers thus determined are then further processed by another module of the control unit 30 or by another module of the computer program. The next module selects at least one driving maneuver from the various possible maneuvers that can be executed (step S8). For this purpose, the subsequent module determines whether the vehicle 10 can reach the individual spatial-temporal sub-areas Ti at all, taking into account the vehicle 10's instantaneous speed, maximum deceleration, maximum acceleration, and / or any speed limit that may be present on road 12. Sub-areas Ti that are not reachable are filtered out by the subsequent module and are no longer considered. Next, the module calculates a trajectory for vehicle 10 that corresponds to at least one driving maneuver (step S9). If several driving maneuvers are available, a corresponding trajectory is determined for each of these maneuvers. In order to determine the trajectory that will ultimately be used by the control unit 30 to control the motor vehicle 10, various filters and / or conditions can be applied to or imposed on the trajectories. For example, the trajectory to be executed must be collision-free and should not require any longitudinal and / or lateral accelerations of the motor vehicle 10 that are greater than a predefined limit acceleration. Finally, one of the possible trajectories is selected and the motor vehicle 10 is controlled at least partially automatically, in particular fully automatically, by the control unit 30 according to the selected driving maneuver (step S10). Alternatively or additionally, information about the selected driving maneuver can be displayed to the driver of motor vehicle 10. In particular, several possible driving maneuvers are selected, and the driver can decide which of the possible maneuvers to execute.

Claims

Method for steering a motor vehicle (10) traveling on a road (12) in an instantaneous lane (14), wherein the road (12) has at least one further lane (16) adjacent to the instantaneous lane (14) of the motor vehicle (10), comprising the following steps: - Determining free areas (Bf) and / or occupied areas (Bb) occupied by other road users (18, 20), at least in the instantaneous lane (14) of the motor vehicle (10) and in the at least one further lane (14), wherein the free areas (Bf) and the occupied areas (Bb) are spatial-temporal areas;- Determining lane-change zones where a lane change between the two lanes (14, 16) is possible, and / or lane-keeping zones where a lane change between the two lanes (14, 16) is not possible, based on the determined free zones (Bf) and / or occupied zones (Bb), wherein the lane-change zones and the lane-keeping zones are each a spatiotemporal sub-zone (Ti) of the free zones (Bf); and - Determining possible driving maneuvers of the motor vehicle (10) at least between pairwise adjacent lane-change zones and / or lane-keeping zones; characterized in that a lane vertex (Vi) is assigned to each lane-change zone and / or lane-keeping zone of the two lanes, wherein the lane vertices (Vi) are connected pairwise by edges if a driving maneuver of the motor vehicle (10) is possible between the corresponding lane-change zones and / or lane-keeping zones. Method according to claim 1, characterized in that the switching areas are those sub-areas (Ti) of the free areas (Bf) of the current lane (14) and of the at least one further lane (16) in which both the current lane (14) and the at least one further lane (16) are free of other road users (18, 20). Method according to claim 1 or 2, characterized in that the lane keeping areas are those sub-areas (Ti) of the free areas (Bf) of the current lane (14) and of the at least one further lane (16) in which the other of the lanes (14, 16) is occupied and / or a lane change is otherwise not possible. Method according to one of the preceding claims, characterized in that, to determine the change zones, it is determined whether a lane change zone (21), which is spatially located between the current lane (14) and the at least one further lane (16), is free, occupied by other road users (18, 20) or otherwise impassable. A method according to one of the preceding claims, characterized in that at least one space-time polygon corresponding to the current lane (14), at least one corresponding to at least one further lane (16) and at least one corresponding to the occupied areas (Bb) is determined, wherein space-time polygons corresponding to the free areas (Bf) of the two lanes are determined from the determined polygons by means of polygon clipping, in particular wherein those polygons that correspond to the occupied areas are removed from the polygons that correspond to one of the two lanes (14, 16) in order to determine the free areas (Bf). Method according to claim 5, characterized in that an intersection of the two polygons is formed which correspond to the free areas (Bf) in the two lanes (14, 16) in order to determine the change zones and lane keeping zones, in particular to determine whether the lane change zone (21) is free. Method according to one of the preceding claims, characterized in that at least the current lane (14) and / or the at least one further lane (16) are transformed into a Frenet-Serret coordinate system. Method according to one of the preceding claims, characterized in that the trace vertices (Vi) are time-ordered. Method according to claim 3, characterized in that at least one lane change zone vertex (Wi) is assigned to the lane change zone (21), in particular wherein the lane change zone (21) is divided into several time strips, each of which is assigned at least one lane change zone vertex (Wi), wherein the at least one lane change zone vertex (Wi) is connected pairwise to the lane vertices (Vi) by edges, if a driving maneuver of the motor vehicle (10) between the corresponding sub-area (Ti) of the lane change zone (21) and the corresponding change area or lane keeping area is possible. Method according to one of the preceding claims, characterized in that several different driving maneuvers for the motor vehicle (10) are determined, in particular all possible driving maneuvers. Method according to one of the preceding claims, characterized in that when determining the free areas (Bf) and / or areas occupied by other road users (Bb), predicted trajectories of the other road users (18, 20) are taken into account. Method according to one of the preceding claims, characterized in that it is determined whether the motor vehicle (10) can reach the respective spatial-temporal sub-areas (Ti), in particular taking into account an instantaneous speed of the motor vehicle (10), a maximum deceleration of the motor vehicle (10), a maximum acceleration of the motor vehicle (10) and / or a speed limit. Method according to one of the preceding claims, characterized in that trajectories of the motor vehicle (10) corresponding to the driving maneuvers are determined. Method according to one of the preceding claims, characterized in that at least one sensor (28) detects the current lane (14) and / or the at least one further lane (16) in order to determine the free areas (Bf), occupied areas (Bb) and / or impassability. Method according to one of the preceding claims, characterized in that at least one of the possible driving maneuvers is selected and the driver is given instructions based on the at least one driving maneuver. Method according to one of the preceding claims, characterized in that one of the possible driving maneuvers is selected and the motor vehicle (10) is controlled according to the selected driving maneuver. Control unit (30) for a system (26) for controlling a motor vehicle (10), wherein the control unit (30) is configured to perform a method according to one of the preceding claims. System (26) for controlling a motor vehicle (10), comprising a control unit (30) according to claim 17. Computer program with program code means to perform the steps of a method according to any one of claims 1 to 16, when the computer program is executed on a computer or a corresponding computing unit (34), in particular a computing unit (34) of a control device (30) according to claim 17. Computer-readable data carrier (32) on which a computer program according to claim 19 is stored.

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