METHOD FOR OPERATING A VEHICLE

Description

[0001] The invention relates to a method for operating a vehicle in automated driving mode according to the preamble of patent claim 1.

[0002] Such a method is known from US 2019 / 389 487 A1. In this known method, the rear area of ​​an automated vehicle is monitored and determined whether the distance to a following vehicle is sufficient to allow the following vehicle to stop safely. If this is not the case, a corresponding notification is issued to the driver of the vehicle and to the following vehicle.

[0003] From DE 10 2018 222 720 A1 a control system for controlling an autonomous or automated vehicle is known, wherein the control system has a first control device based on artificial intelligence and a second control device based on deterministic calculation rules, and wherein a criticality of a driving situation is determined and, depending on the determined criticality, a switchover from the first control device to the second control device is carried out.

[0004] From EP 3 552 901 A2 a method for operating a vehicle in an automated driving mode is known, wherein it is provided that a driver of the vehicle is requested to take over the driving task upon detection of certain events, and that a minimal risk maneuver is carried out if the driver does not take over the driving task.

[0005] DE 10 2018 204 572 A1 discloses a control unit of a vehicle and a method for protecting the vehicle from a rear-end collision. The vehicle has an emergency braking function configured to automatically initiate emergency braking of the vehicle. The method provides that the control unit determines that there is an increased probability of automatic emergency braking. In response, at least one warning signal is generated to prompt a following vehicle to maintain a sufficiently high safety distance from the vehicle.

[0006] Furthermore, DE 103 28 755 A1 describes a system for preventing a following vehicle from maintaining an insufficient distance from a vehicle in front, in particular a motor vehicle. For this purpose, the vehicle in front has a device for determining the distance to the following vehicle and for determining the relative speed with respect to the following vehicle. Based on the determined distance and the relative speed, a minimum distance is determined. If the minimum distance is exceeded, measures are implemented to prevent a further reduction in the distance, thus avoiding a potential rear-end collision.

[0007] The invention is based on the object of specifying a method for operating a vehicle in automated driving mode.

[0008] The object is achieved according to the invention by a method which has the features specified in claim 1.

[0009] Advantageous embodiments of the invention are the subject of the subclaims.

[0010] A method for operating a vehicle in automated driving mode provides, according to the invention, for continuously monitoring the rear area of ​​the vehicle. If a following vehicle is detected to be critically approaching the vehicle, a warning is issued to the following vehicle. If the following vehicle continues to approach the vehicle critically after a predefined period of time, a takeover request regarding a driving task is issued to a vehicle user of the vehicle.

[0011] By applying the procedure, the risk of an accident between the vehicle and the following vehicle can be reduced.

[0012] The procedure represents a method for preemptively alerting the following vehicle to maintain an adequate distance from the vehicle, allowing the distance to the vehicle to be increased, thus giving the driver of the following vehicle the opportunity to react to an unexpected braking maneuver by the vehicle, for example, due to an incorrectly detected obstacle, a so-called false object or ghost object. The procedure thus provides additional protection against a collision with the following vehicle due to improper braking by the vehicle operating in automated driving mode.

[0013] The distance between the two vehicles, in particular a safety distance that enables the following vehicle to react to an emergency braking maneuver, is speed-dependent, since the braking distance of the following vehicle increases with increasing driving speed.

[0014] If the procedure is applied, the acceptance of automated driving of vehicles that may have deficiencies can be increased.

[0015] In one embodiment of the method, if the driving task has not been taken over after a predefined period of time, the vehicle's current speed is reduced by a predefined value until the critical proximity between the following vehicle and the vehicle no longer exists. For example, the vehicle may not take over because the vehicle is driverless or a vehicle user is unable to perform the driving task manually, for example, due to an emergency.

[0016] The vehicle reduces its speed, particularly to signal to the following vehicle that it is offering to overtake, or to indicate again that the following vehicle has approached the vehicle too close and is therefore unable to react to an abrupt braking maneuver. Reducing speed can also reduce the risk of detecting ghost targets.

[0017] In another possible embodiment of the method, after the additional time period has elapsed, the vehicle is controlled such that it positions itself in a right-hand edge area within its lane in the case of right-hand traffic, or in a left-hand edge area within its lane in the case of left-hand traffic. In particular, the vehicle continues its automated driving operation at the reduced speed. This process is therefore carried out if the takeover request is not complied with and the vehicle reduces its speed by the specified value. In particular, the vehicle drives to a right-hand or left-hand lane marking and reduces its speed so that the following vehicle is signaled to overtake the vehicle and can therefore no longer approach the vehicle critically.The following vehicle then no longer poses a risk of collision for the vehicle if the latter initiates an abrupt braking maneuver, particularly due to an incorrectly detected object.

[0018] In a further development of the vehicle, the warning to the following vehicle can be issued as a text message on a display unit located at the rear of the vehicle. In particular, the text message includes a request to increase the distance between the following vehicle and the vehicle.

[0019] In an alternative or additional embodiment, the warning is issued to the following vehicle via vehicle-to-vehicle communication. This makes it possible for the driver of the following vehicle to be warned directly, i.e., the warning is issued directly to the driver of the following vehicle. The warning is thus addressed directly to the driver of the following vehicle.

[0020] In a further embodiment of the method, the time period before the takeover request is issued in the vehicle is at least 30 seconds. This means that the takeover request is issued no earlier than 30 seconds after the warning is issued to the following vehicle or in the following vehicle. The following vehicle is thus given at least 30 seconds, which is sufficient time, to react to the vehicle's warning and increase its distance from the automated vehicle.

[0021] Embodiments of the invention are explained in more detail below with reference to a drawing.

[0022] Showing: Fig. 1 schematically shows a road section with two opposing lanes, an automated vehicle, a following vehicle, an oncoming vehicle and a ghost object and Fig. 2 schematically shows a road section with two opposing lanes, the automated vehicle, the following vehicle and the ghost object when applying a method for reducing a rear-end collision.

[0023] Corresponding parts are provided with the same reference numerals in all figures.

[0024] Figure 1 shows a road section F with two opposing lanes F1, F2. In a right lane F1, a vehicle 1 is traveling in automated driving mode, and a vehicle 2 is following vehicle 1. In a left lane F2, an oncoming vehicle 3 is traveling.

[0025] The vehicle 1 has an assistance system for automated driving, whereby the vehicle 1, in particular the assistance system, fully performs a driving task so that a vehicle user can pursue another activity during automated driving.

[0026] The assistance system comprises an environmental sensor system with a number of detection units arranged in and / or on the vehicle 1, at least one of which is designed as a sensor system 4 and includes a camera 4.1. The sensor system 4 in the form of the camera 4.1 is arranged in or on the vehicle 1 such that a detection area (not shown in detail) is directed in front of the vehicle 1 and thus a region of the road section F ahead of the vehicle 1 is detected.

[0027] Based on signals recorded by the environmental sensors, including camera 4.1, obstacles in the surroundings of vehicle 1 are detected. A control unit of the environmental sensors determines the criticality of a current situation, particularly with regard to a detected obstacle. Depending on the determined criticality, particularly if it exceeds a predefined threshold, a braking process of vehicle 1 is initiated, for example, to reduce the risk of collision between vehicle 1 and the obstacle.

[0028] Occasionally, a situation may arise in which a false object 5, i.e., a so-called ghost object, is detected by the sensor system 4. Such a false object is an object and thus an obstacle that is detected by the sensor system 4, but does not actually exist. Such a false object 5 leads to an incorrectly initiated braking maneuver during automated driving of the vehicle 1. This means that the vehicle 1 initiates a braking maneuver, e.g., an emergency braking maneuver, without any externally identifiable reason.

[0029] Such an initiated braking action on an incorrect object 5, a so-called false positive error, can lead to a rear-end collision between vehicle 1 and the following vehicle 2. In particular, there is a risk of a rear-end collision if the following vehicle does not maintain a sufficiently large distance from vehicle 1, i.e., approaches it critically.

[0030] Such a rear-end collision can be avoided by maintaining a sufficiently large distance between vehicle 1 and the following vehicle 2. For vehicle 1 driving in automated mode, it is not possible to directly set a sufficiently large distance to the following vehicle 2, since distance control is implemented by the following vehicle 2.

[0031] In order to significantly reduce the risk of such a rear-end collision based on an insufficient distance between vehicle 1 and the following vehicle 2, a procedure described below is provided.

[0032] Figure 2 shows a road section F with two opposing lanes F1, F2, with vehicle 1 driving in automated driving mode on the right lane F1 and a following vehicle 2 driving behind vehicle 1, which is critically approaching vehicle 1 from behind.

[0033] The environmental sensor system comprises at least one detection unit, for example a radar-based detection unit, which monitors a rear area of ​​the vehicle, ie an area behind the vehicle 1, at least during the automated driving operation of the vehicle 1.

[0034] If the following vehicle 2 is detected based on signals from the ambient sensors, a distance a 1 and thus a time gap t 1 are determined, which the following vehicle 2 typically requires to avoid a rear-end collision if the vehicle 1 initiates an improper braking maneuver due to a detected false object 5. This distance a 1 and the time gap t 1 can be speed-dependent, in particular.

[0035] If the following vehicle 2 has approached the vehicle 1 so critically that a further distance a 2 and a further time gap t 2 are not sufficient, that a rear-end collision between the following vehicle 2 and the vehicle 1 is unavoidable in the event of a false braking initiated by the latter due to a detected false object 5, the vehicle 1 issues a warning to the following vehicle 2.

[0036] In one embodiment, the vehicle's warning W is output to the following vehicle 2 by means of a displayed text message. For this purpose, a display unit 6 is arranged in the rear area of ​​the vehicle 1. In particular, the text message contains a request to increase the current distance a 2 of the following vehicle 2 from the vehicle 1 if the distance a 1 and thus the time gap t 1 are exceeded.

[0037] Alternatively or additionally, the warning W is transmitted to the following vehicle 2 via vehicle-to-vehicle communication and displayed there. A driver of the following vehicle 2 is thereby warned directly, in particular via an active safety assistance system.

[0038] If the following vehicle 2 continues to approach the vehicle 1 critically, whereby the distance a 1 and the time gap t 1 are undershot, after a predeterminable period of time of, for example, 30 seconds, a takeover request is issued in the vehicle 1, so that a vehicle user of the vehicle 1 manually carries out a driving task of the vehicle 1.

[0039] If the driving task has not been taken over after a further period of time, for example because there is no vehicle occupant in vehicle 1 or the vehicle occupant cannot perform the driving task due to an emergency, vehicle 1 reduces its current driving speed by a specified value. This signals the following vehicle 2 to overtake vehicle 1, taking into account at least one oncoming traffic.

[0040] Additionally, after the additional time period has elapsed, vehicle 1 can position itself within its lane F1 in the area of ​​a right-hand lane marking M and continue its automated driving operation there at the reduced speed. By positioning itself within the area of ​​the right-hand lane marking M and at the reduced speed, the following vehicle 2 is prompted to perform an overtaking maneuver without endangering other road users.

[0041] If the following vehicle 2 has overtaken vehicle 1 or increased the further distance a 2 to at least the distance a 1, vehicle 1 positions itself centrally in relation to its right lane F1 and increases the current driving speed to a driving speed permissible for automated driving operation, in particular to a driving speed applicable for the road section.

Claims

1. Method for operating a vehicle (1) in automated driving mode, wherein - a rear area of the vehicle (1) is continuously monitored, - in the event of a detected critical approach of a following vehicle (2) to the vehicle (1), a warning message (W) is output to the following vehicle (2) characterized in that - in the event that the following vehicle (2) continues the critical approach to the vehicle (1) after a predeterminable period of time, a takeover request with regard to a driving task is output to a vehicle user of the vehicle (1).

2. Method according to claim 1, characterized in that in the event that the driving task has not been taken over after a predeterminable further period of time, a current driving speed of the vehicle (1) is reduced by a predeterminable value until the critical approach between the following vehicle (2) and the vehicle (1) no longer exists.

3. Method according to claim 2, characterized in that after the further time period has elapsed, the vehicle (1) is controlled in such a way that it positions itself in a right-hand side region within its lane (F1) in the case of right-hand traffic or in a left-hand side region within its lane (F2) in the case of left-hand traffic.

4. Method according to any of the preceding claims, characterized in that the warning message (W) is output to the following vehicle (2) as a text message on a display unit (6) of the vehicle (1) arranged at the rear thereof.

5. Method according to any of the preceding claims, characterized in that the warning message (W) is transmitted to the following vehicle (2) by means of vehicle-to-vehicle communication.

6. Method according to any of the preceding claims, characterized in that the time period before the takeover request is output in the vehicle (1) is at least 30 seconds.