Method for operating lane change assistance system of vehicle by taking into account traffic density in surroundings of vehicle, lane change assistance system and vehicle

Abstract

The invention relates to a method for operating a lane change assistance system (2) of a vehicle (1), comprising the following steps: detecting environmental data describing the surroundings of the vehicle (1), detecting further traffic participants (12) in the surroundings on the basis of the environmental data, planning a course of a lane change maneuver from an initial lane (13) to a target lane (14), wherein during the lane change maneuver a certain transverse dynamic effect is caused to act on the vehicle (1), a traffic density in the surroundings is determined, the traffic density describing the number, distribution and / or movement of the further traffic users (12), and a planning trend (T1) of the lane change maneuver is adjusted as a function of the determined traffic density, the invention relates to a method for changing lateral dynamics during a lane change maneuver.

Description

Technical Field

[0001] The invention relates to a method for operating a lane change assist system of a vehicle. The invention also relates to a lane change assist system for a vehicle. Finally, the invention relates to a vehicle having such a lane change assist system. Background Art

[0002] Lane change assistance systems for vehicles are well known from the prior art. In known lane change assistance systems with an automated or automatic lane change function, the driver usually indicates a lane change intention by a certain operator control, such as actuating a turn signal stalk. If such an operator control is detected, the vehicle is automatically guided laterally and generally also longitudinally along the planned trajectory by means of the lane change assistance system into an adjacent lane or a target lane. During the lane change maneuver, lateral dynamics are generated that act on the vehicle and thus on the vehicle occupants.

[0003] The current design of lane change assist systems is mainly aimed at being able to provide lane changes and successfully execute them even under more dynamic conditions within the scope of legal requirements. For example, all lane change maneuvers can be planned in such a way that the same lateral dynamics act on the vehicle during each lane change maneuver. The only change in dynamics is achieved through the speed of the vehicle.

[0004] Furthermore, it is known from the prior art that driver assistance systems can be adapted to the driver's driving style. In this context, for example, DE 10 2017 208 583 A1 describes a driving system for a vehicle, which is configured to automatically guide the vehicle at least partially and / or temporarily according to a determined driving style. In this case, the driving style of the autonomously driven vehicle can be automatically adjusted based on passenger sensor data. For example, the trajectory can be adapted to the longitudinal and / or lateral acceleration.

[0005] In addition, additional complex methods for evaluating gaps between other traffic participants on the target lane are known from the prior art. These methods for gap evaluation are used, for example, to make a decision on whether a lane change can be performed. For example, this method is disclosed in DE 10 2015 203 208 A1. Summary of the invention

[0006] The object of the present invention is to provide a solution for how a lane change assistance system of the type mentioned at the outset can be operated in a situation-dependent manner. In addition, a vehicle having a corresponding lane change assistance system is to be provided.

[0007] This object is achieved according to the invention by a method, a lane change assistance system and a vehicle having the features according to the independent claims. Advantageous developments of the invention are specified in the dependent claims.

[0008] The method according to the invention is used to operate a lane change assistance system of a vehicle. The method comprises detecting environmental data describing the surroundings of the vehicle. In addition, the method comprises detecting other traffic participants in the surroundings based on the environmental data. The method also comprises planning the course of a lane change maneuver from an initial lane to a target lane, wherein during the lane change maneuver, certain lateral dynamics are caused to act on the vehicle. In addition, the method comprises determining a traffic density in the surroundings, wherein the traffic density describes the number, distribution and / or movement of other traffic participants. In addition, the method comprises adjusting the planned course of the lane change maneuver based on the determined traffic density to prevent lateral dynamics during the lane change maneuver.

[0009] The lane change assistance system may have at least one environmental sensor or distance sensor. Environmental data may be provided by means of the environmental sensor or distance sensor. The environmental data describe the surroundings or environment of the vehicle. In particular, the environmental data may be detected based on other traffic participants in the vehicle's surroundings. Preferably, the relative position of the other traffic participants to the vehicle may be determined.

[0010] Lane change assist systems can be used to plan a lane change maneuver from the initial lane in which the vehicle is currently located to a target lane or an adjacent lane. For example, a corresponding trajectory along which the vehicle is to be maneuvered can be calculated for this purpose. For planning a lane change maneuver, it can be checked whether there is a free gap for the vehicle between other traffic participants in the target lane. If a gap is detected, it can be checked whether the gap is of a suitable size for the lane change maneuver.

[0011] The lane change maneuver can then usually be initiated or started after a predetermined operating procedure has been detected, for example after the driver has actuated a turn signal lever. It can also be provided that the lane change maneuver is started automatically or automatically with the aid of a lane change assistance system. If a suitable free space between other traffic participants in the target lane is identified, the vehicle can be at least partially automatically steered into the target lane or an adjacent lane with the aid of a lane change assistance system. In this case, the lane change assistance system can intervene in the steering of the vehicle or take over the lateral guidance. It is also preferably provided that the longitudinal guidance of the vehicle is also taken over when the lane change maneuver is automatically performed with the aid of a driver assistance system.

[0012] When executing a lane change maneuver, lateral dynamics are generated which act on the vehicle and thus on the vehicle occupants. The lateral dynamics can be derived from the planned trajectory along which the vehicle is maneuvered from the initial lane to the target lane. The lateral dynamics can describe lateral acceleration, lateral impact, changes in the steering angle, etc. The lateral dynamics can also be related to the current longitudinal speed of the vehicle. Depending on the lateral dynamics during the lane change maneuver, a corresponding perception of the lateral dynamics is generated for the driver or occupants of the vehicle.

[0013] As already explained at the outset, it is known from the prior art to execute or plan each lane change maneuver with the same lateral dynamics. It should therefore be possible to successfully execute lane changes even under dynamic conditions. However, this can lead to the lane change maneuver being perceived as too dynamic by the vehicle occupants, for example, in completely free travel without other road users in the target lane.

[0014] According to the invention, it is now provided that the current traffic density in the vehicle surroundings is determined based on the environmental data. On the one hand, the traffic density can describe the number of traffic participants in the vehicle surroundings. In addition, the traffic density can describe the distribution of traffic participants. For example, the traffic density can describe the number of other traffic participants on the target lane, on the initial lane and / or, if necessary, on other existing lanes. In addition, it can be provided that the traffic density describes the movement of other traffic participants. In particular, the traffic density can describe the speed of other traffic participants, which speed is determined based on the environmental data.

[0015] Furthermore, it is provided according to the invention that the planned course of the lane change maneuver is adjusted as a function of the determined traffic density. By adjusting the lane change maneuver, a change in the transverse dynamics can be achieved during the lane change maneuver. In particular, the trajectory along which the vehicle is maneuvered from the initial lane into the target lane can be adjusted. The current longitudinal speed of the vehicle can be taken into account in this regard.

[0016] The invention is based on the knowledge that the lateral dynamics perceived as comfortable can vary greatly during a lane change maneuver in different traffic situations. With the method according to the invention, a dynamic change can be introduced with respect to different traffic situations, so that the lane change maneuver performed is always perceived as comfortable, safe and appropriate to the situation. It is thus possible to vary and adjust the dynamics during an automatic lane change depending on the traffic situation, so that maximum comfort is achieved and a natural traffic flow is ensured.

[0017] Preferably, the planning course of the lane change maneuver is adjusted so that the lateral dynamics during the lane change maneuver increases with increasing traffic density. For example, if a lane change maneuver is to be performed or requested by the driver, the current traffic density in the vehicle's surroundings can be determined. Based on the determined traffic density, the subsequent lane change maneuver can then be planned in a situation-adapted manner. For example, different trajectories can be saved for different traffic densities or different traffic conditions, which can then be selected accordingly depending on the current speed. Furthermore, it can be provided that a maximum lateral dynamics is predefined as a function of the traffic density, and the trajectory can then be planned based on this maximum lateral dynamics. In other words, the trajectory is planned depending on the traffic situation or traffic density so that the predefined maximum lateral dynamics is not exceeded during the lane change maneuver.

[0018] However, in principle, the lane change maneuver or the course of the lane change maneuver can be adjusted in such a way that, when the traffic density is relatively high, the lane change maneuver is performed with relatively high lateral dynamics. Conversely, when the traffic density is low, the lane change maneuver can be adjusted so that low lateral dynamics occur. In this way, it can be achieved that the driver or other passengers perceive the lane change maneuver that is automatically performed in relation to the current traffic situation as comfortable and safe.

[0019] Furthermore, advantageously, when determining the traffic density, the size of the gap between other road users in the target lane for the lane change maneuver is determined, and the course of the planned lane change maneuver is adjusted as a function of the size of the gap. When determining the traffic situation in the vehicle's surroundings, it can first be checked whether there is a free gap in the target lane. If such a free gap exists, the size of the gap can be determined.

[0020] In particular, it is provided that the size of the gap is determined along the direction of travel or along the main extension direction of the target lane. In other words, the length of the gap can be determined. If the gap is sufficient for a lane change maneuver of the vehicle, the trajectory or course of the planned lane change maneuver can be adapted to the size of the gap. For example, the lateral dynamics can be reduced when the gap is large, so that the vehicle occupants can achieve a lane change that is as comfortable as possible. Conversely, the lateral dynamics can be increased when the gap is small, so that the lane change maneuver can be performed safely.

[0021] In another specific embodiment, the speed of at least one other road user that limits the gap for the lane change maneuver is determined when determining the traffic density, and the course of the planned lane change maneuver is adjusted as a function of this speed. In particular, the speed of a road user approaching the gap from behind can be determined. For example, if this road user is catching up with other road users driving ahead or other road users limiting the gap at an increased speed, this road user can reduce or close the gap that is still present. This can occur in the same way if the road user limiting the gap ahead reduces his speed.

[0022] Based on the speed of the corresponding road user limiting the gap, it can be determined whether a reduction in the size of the gap is imminent. If such a gap closure is imminent, the lane change maneuver can be planned so that it is performed with relatively high lateral dynamics, so that the lane change maneuver can be performed safely. However, if there is a sufficiently large gap and, for example, the road user limiting the gap does not change speed or the road user behind the road user limiting the gap slows down, the lane change maneuver can be performed with less lateral dynamics.

[0023] In another specific embodiment, the course of the planned lane change maneuver is adjusted to achieve minimum lateral dynamics during the lane change maneuver if no other traffic participants are present in the target lane at a predetermined distance from the vehicle. For example, if no other traffic participants can be detected in the detection range of the at least one surroundings sensor in the target lane, the lane change maneuver can be planned with minimum lateral dynamics. Thus, maximum comfort can be achieved during the lane change maneuver.

[0024] Furthermore, it can be provided that the presence of other traffic participants in the initial lane is checked. In particular, it can be checked whether there are other traffic participants in the initial lane and in front of the own vehicle. In this case, the distance of the other traffic participant to the vehicle can also be checked. Furthermore, the speed of the other traffic participant in front of the vehicle in the target lane can be checked. For example, if the traffic participant reduces speed, a lane change maneuver can be planned with greater lateral dynamics.

[0025] In addition, it is possible to check whether there are other traffic participants in the lane adjacent to the target lane. In this case, the course of the planned lane change maneuver can be adjusted according to the presence of other traffic participants in the lane adjacent to the target lane. The lane adjacent to the target lane can be arranged on the side of the target lane opposite to the initial lane. In this case, if there is another traffic participant in the lane adjacent to the target lane or in the next lane, the lateral dynamics of the lane change maneuver can be reduced. This is particularly suitable for situations where other traffic participants are located in the area of ​​the gap or at the height of the gap.

[0026] In addition, the lateral dynamics can be adjusted according to the size and / or distance of other traffic participants in the lane adjacent to the target lane. In the case of other traffic participants with large sizes, such as in the case of heavy vehicles, the lateral dynamics can be reduced. Here, if the driver or passengers move towards such traffic participants during the lane change maneuver, they may feel uneasy. The same applies if other traffic participants are very close to the target lane or even partially extend into the target lane. In these cases, relatively low lateral dynamics can also be selected for the lane change maneuver.

[0027] In another embodiment, it is checked whether the vehicle driver has his hands on the steering wheel and the course of the planned lane change maneuver is additionally determined as a function of whether the driver has his hands on the steering wheel. Depending on the design of the driver assistance system or the lane change assistance system, it can be provided that the driver must have his hands on the steering wheel during the operation of the lane change assistance system. In this case, the lane change maneuver can be performed with greater lateral dynamics. If the driver has his hands on the steering wheel, the stronger steering intervention by the driver assistance system, for example, during the lane change maneuver, may not be perceived as a disturbance by the driver. In a so-called hands-off system, the driver can at least partially remove his hands from the steering wheel, wherein less lateral dynamics can be selected. If the driver does not currently have his hands on the steering wheel, the driver will not be disturbed by the comfortable lane change maneuver.

[0028] As already explained, a lane change maneuver can be triggered or initiated based on a detected driver's operating decision, but can also be triggered or initiated automatically without the driver's operating decision. If the lane change maneuver is initiated due to the driver's operating decision, a higher lateral dynamics can be selected during the lane change maneuver than in the case of an automatically initiated lane change maneuver. If the driver triggers the lane change maneuver by the operating decision itself, the driver will expect to perform a lane change subsequently. However, if the lane change is automatically initiated by the lane change assist system, the driver may be surprised. This surprise of the driver can be reduced by a low lateral dynamics during the lane change maneuver.

[0029] A lane change assist system for a vehicle according to the present invention is configured to detect environmental data describing the vehicle's surroundings. In addition, the lane change assist system is also configured to detect other traffic participants in the surroundings based on the environmental data. In addition, the lane change assist system is configured to plan the course of a lane change maneuver from an initial lane to a target lane, wherein a certain lateral dynamics is caused to act on the vehicle during the lane change maneuver. In addition, the lane change assist system is configured to determine a traffic density in the surroundings, wherein the traffic density describes the number, distribution and / or movement of other traffic participants. Finally, the lane change assist system is configured to adjust the planned course of the lane change maneuver based on the determined traffic density in order to change the lateral dynamics during the lane change maneuver.

[0030] As already explained, the lane change assist system may have at least one environment sensor, which may be designed, for example, as a camera, a radar sensor, a lidar sensor, etc. Furthermore, the lane change assist system may have a computing device, which may be formed by at least one electronic control unit, a processor, etc. Based on the environment data of the environment sensor, the traffic density in the surroundings of the vehicle may be determined by means of the computing device.

[0031] Furthermore, the computing device can be used to plan a lane change maneuver or a trajectory for maneuvering the vehicle from an initial lane into a target lane. The computing device can adjust the trajectory as a function of the determined traffic density. Furthermore, the lane change assist system can have a steering wheel sensor, with the aid of which it can be determined whether the driver currently has his hands on the steering wheel. Depending on whether the driver has his hands on the steering wheel, the computing device can additionally adjust the trajectory or course of the lane change maneuver.

[0032] Furthermore, the computing device can be designed to output a control signal to actuate the steering or a steering system of the vehicle. By actuating the steering, the lateral guidance of the vehicle can then be taken over during the lane change maneuver. Furthermore, it can be provided that the longitudinal guidance of the vehicle during the lane change maneuver is performed by means of the lane change assist system.

[0033] A vehicle according to the invention comprises a lane change assistance system according to the invention. The vehicle is in particular designed as a passenger car.

[0034] The preferred embodiments presented with reference to the method according to the invention and their advantages apply correspondingly to the lane change assistance system according to the invention and the vehicle according to the invention.

[0035] Further features of the invention are apparent from the claims, the drawings and the description of the drawings. The features and feature combinations mentioned above in the description of the drawings and the features and feature combinations mentioned below in the description of the drawings and / or shown individually in the drawings can be used not only in the correspondingly given combination but also in other combinations or individually without departing from the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will now be described in detail according to preferred embodiments and with reference to the accompanying drawings. It is shown here:

[0037] Figure 1 : A schematic diagram of a vehicle having a lane change assist system for performing an automated lane change maneuver;

[0038] Figure 2 : a vehicle in a first traffic situation before performing a lane change maneuver; and

[0039] Figure 3 : A vehicle that is in a second traffic situation before performing the lane change maneuver. DETAILED DESCRIPTION

[0040] Figure 1 A vehicle 1, which is in the present case designed as a passenger car, is shown in a top view. Vehicle 1 comprises a lane change assist system 2, by means of which an automatic lane change maneuver can be performed with vehicle 1. Lane change assist system 2 comprises a computing device 3, which can be formed, for example, by at least one electronic control unit of vehicle 1.

[0041] Furthermore, the lane change assist system 2 includes at least one environmental sensor 4. In the present example, the lane change assist system 2 includes four environmental sensors 4, of which two environmental sensors 4 are arranged in the front area 6a and two environmental sensors 4 are arranged in the rear area 6b. In this case, the environmental sensors 4 are arranged in the corners of the vehicle 1. The environmental sensors 4 can be designed as radar sensors, for example. The environmental sensors 4 can be used to perform corresponding measurements and provide environmental data in order to detect other road users 12 in the surroundings 5 ​​of the vehicle 1.

[0042] The computing device 3 is also configured to detect a predetermined operating action performed by the driver on the operating element 8. The operating element 8 can be, for example, a turn signal lever. Due to the actuation of the operating element 8, the driving direction indicator 11, which is currently only shown, can be activated. In addition, the computing device 3 can detect whether the driver currently has his hands on the steering wheel of the vehicle 1.

[0043] Furthermore, the computing device 3 is configured to control a steering system 9, which is only schematically shown here, of the vehicle 1. By controlling the steering system 9, a lateral guidance of the vehicle 1 can be performed during a lane change maneuver. By controlling the steering system 9, steerable wheels 10 of the vehicle 1 can be steered and can thus take over the lateral guidance during a lane change maneuver.

[0044] The computing device 3 is also configured to determine the traffic density in the surroundings 5 ​​of the vehicle 1 based on the environmental data of the environmental sensors 4 . The traffic density may describe the number, distribution and / or movement of other road users 12 .

[0045] Figure 2 A vehicle 1 is shown in a first traffic situation. In this case, the vehicle 1 is located in an initial lane 13. A lane change maneuver from the initial lane 13 to the target lane 14 is to be performed with the vehicle 1. Before the lane change maneuver is actually performed, the course of the lane change maneuver from the initial lane 13 to the target lane 14 is planned with the aid of the lane change assistance system 2 or the computing device 3. For this purpose, corresponding trajectories T1, T2 are determined along which the vehicle 1 is maneuvered from the initial lane 13 to the target lane 14. In this arrangement, the course or trajectory T1, T2 of the lane change maneuver is adjusted depending on the traffic density.

[0046] Furthermore, the course or trajectory T1, T2 can be adjusted depending on whether the driver currently has his hands on the steering wheel of vehicle 1. If the driver has his hands on the steering wheel, a higher lateral dynamics can be selected than if the driver does not have his hands on the steering wheel.

[0047] exist Figure 2 In the example of , there is a high traffic density. In this case, in front of the vehicle 1 in the direction of travel, another traffic participant 12 is located in the initial lane 13. In the present schematic diagram, two further traffic participants 12 are located in the target lane 14, which bound a gap 15. The lateral dynamics acting on the vehicle 1 or the occupants of the vehicle 1 during the lane change maneuver are influenced by the planning of the trajectory T1. At the current high traffic density, a first trajectory T1 is determined, which leads to relatively high lateral dynamics during the lane change maneuver. At this high traffic density, it should be ensured that a lane change maneuver into the gap 15 can be reliably performed.

[0048] Furthermore, the size of the gap can be determined and taken into account when planning the trajectory T1. In particular, the size or length l of the gap 15 in the direction of travel or in the main extension direction of the target lane 14 is determined. Alternatively or additionally, the corresponding speed of other road users 12 that bound the gap 15 can be determined. Alternatively or additionally, in particular, the speed of a road user 12 approaching the gap from behind can be determined. If this road user 12 has an increased speed, the gap can be closed. If this situation is encountered, the lateral dynamics can be increased during a lane change maneuver.

[0049] In contrast, Figure 3 The schematic diagram of the vehicle 1 according to a second traffic situation is shown. In this traffic situation, no other road users 15 are present in the initial lane 13 or in the target lane 14. Therefore, in this case, a second trajectory T2 is determined for the lane change maneuver. In this trajectory T2, the smallest possible or minimum lateral dynamics acting on the vehicle 1 are generated. This makes it possible to achieve a particularly comfortable lane change maneuver.

Claims

1. A method for operating a lane change assistance system (2) of a vehicle (1), comprising the following steps: - detecting environmental data describing the surroundings (5) of the vehicle (1), - detecting other road users (12) in the surroundings (5) based on the environmental data, and - planning the course of a lane change maneuver from an initial lane (13) to a target lane (14), wherein during the lane change maneuver a certain lateral dynamic action is brought about on the vehicle (1), It is characterized in that - determining a traffic density in the surroundings (5), wherein the traffic density describes the number, distribution and / or movement of the other traffic participants (12), and - adjusting the planned course of the lane change maneuver as a function of the determined traffic density in order to change the lateral dynamics during the lane change maneuver.

2. The method according to claim 1, It is characterized in that The planned course of the lane change maneuver is adjusted such that the lateral dynamics during the lane change maneuver increases as the traffic density increases.

3. The method according to claim 1 or 2, It is characterized in that When determining the traffic density, the size of a gap (15) between the other road users (12) in the target lane (14) is determined for the lane change maneuver, and the course of the planned lane change maneuver is adjusted as a function of the size of the gap (15).

4. The method according to any one of the preceding claims, It is characterized in that When determining the traffic density: determining a speed of at least one of the other traffic participants (12) which delimits a gap (15) for the lane change maneuver; and adjusting the course of the planned lane change maneuver as a function of the speed.

5. The method according to any one of the preceding claims, It is characterized in that If no other road users (12) are present in the target lane (14) at a predetermined distance from the vehicle (1), the course of the planned lane change maneuver is adjusted in order to achieve minimum lateral dynamics during the lane change maneuver.

6. The method according to any one of the preceding claims, It is characterized in that It is checked whether the driver of the vehicle (1) has his hands on the steering wheel and the course of a planned lane change maneuver is additionally determined as a function of whether the driver has his hands on the steering wheel.

7. A lane change assist system (2) for a vehicle (1), wherein the lane change assist system (2) is configured to: - detecting environmental data describing the surroundings (5) of the vehicle (1), - detecting other road users in the surroundings (5) based on the environmental data, and - planning the course of a lane change maneuver from an initial lane (13) to a target lane (14), wherein during the lane change maneuver a certain lateral dynamic action is brought about on the vehicle (1), It is characterized in that The lane change assistance system (2) is further configured to: - determining a traffic density in the surroundings (5), wherein the traffic density describes the number, distribution and / or movement of the other traffic participants (12), and - adjusting the planned course of the lane change maneuver as a function of the determined traffic density in order to change the lateral dynamics during the lane change maneuver.

8. A vehicle (1), in particular a passenger car, comprising a lane change assistance system (2) according to claim 7.

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