Procedure for automatic emergency braking of a motor vehicle

Abstract

The invention relates to a method for automatic emergency braking (54) of a motor vehicle (10), in which a detection system arranged on the motor vehicle (10) detects moving obstacles (20) and transmits this information to an electronic control unit of the motor vehicle (10). Only when the control unit detects an imminent collision between the motor vehicle (10) and an obstacle (20), which can no longer be avoided by influencing the obstacle (20), is the automatic emergency braking of the motor vehicle (10) triggered.

Description

[0001] The present invention relates to a method for the automatic emergency braking of a motor vehicle. The present invention further relates to a computer program configured to perform each step of the method according to the invention, and to a machine-readable storage medium on which the computer program according to the invention is stored. The invention also relates to an electronic control unit configured to perform automatic emergency braking of a motor vehicle using the method according to the invention. State of the art

[0002] Driver assistance systems for motor vehicles can trigger automatic emergency braking if they detect an imminent risk of a collision with an obstacle. This is intended to prevent accidents that the driver cannot avoid independently due to driving errors, inattention, or an insufficiently quick reaction to a dangerous situation.

[0003] German patent DE 197 38 611 A1 describes such a procedure, which allows the driver maximum decision-making sovereignty when swerving, braking, or accelerating towards obstacles, without foregoing the advantages of a driver-assistance system for collision avoidance or accident severity mitigation in the event of an actual collision. This is achieved by triggering automatic emergency braking only when the driver assistance system determines that a collision with an obstacle can no longer be avoided by the driver's steering and / or braking, given the physics of vehicle handling.

[0004] Driver assistance systems use environmental sensors to detect obstacles. However, due to inaccuracies in these sensors, such as radar sensors, and reflections of radar waves emitted by radar sensors from the surrounding infrastructure, the driver assistance system may falsely detect an obstacle that does not actually exist. Such non-existent obstacles are called ghost objects. If emergency braking is triggered due to the detection of a ghost object, this at best results in a loss of comfort for the driver. At worst, however, the vehicle comes to a standstill in the path of another real vehicle or, due to a reduction in speed, reaches the path of the real vehicle somewhat later, resulting in a collision that would not have occurred without the emergency braking. Disclosure of the invention

[0005] A method for the automatic emergency braking of a motor vehicle is proposed, in which a detection system mounted on the vehicle detects moving obstacles and transmits this information to an electronic control unit of the vehicle. The automatic emergency braking of the vehicle is only triggered when the control unit detects an imminent collision between the vehicle and an obstacle, which can no longer be avoided by influencing the obstacle's position.

[0006] This method has the advantage of minimizing the risk of unnecessary emergency braking due to the presence of ghost objects. The reliability of the obstacle detection system, which includes at least one radar sensor, increases with decreasing distance to the obstacle. By delaying emergency braking until the last possible moment, this method increases the probability that a ghost object will be recognized as such before the automatic emergency braking is triggered, thus preventing an unnecessary emergency stop.

[0007] When an impending collision is detected, a cooperative behavior of the obstacle is preferably assumed. This means that the obstacle's driving behavior is assumed to be geared towards increasing the overall benefit and / or minimizing the overall costs for all road users, rather than solely striving for benefit maximization and / or cost minimization for the obstacle itself without regard for other road users.

[0008] In principle, the method could consider all conceivable driving maneuvers that could influence the obstacle's movement and thus prevent a collision with the vehicle. However, since calculating the effect of evasive maneuvers is particularly difficult, it is preferred that the method only considers the obstacle's movement being influenced by a braking maneuver. To ensure that the vehicle's automatic emergency braking is not delayed for an unreasonably long time, it is further preferred that a predefined safety distance be added to the obstacle's braking distance when the impending collision is detected.

[0009] To detect an impending collision, various parameters of the obstacle and its driver must be known. These include, in particular, the reaction time of the obstacle's driver, the braking force applied by the obstacle's driver, and the braking performance of that braking system. Since the actual values ​​of these parameters cannot be determined in an imminent collision scenario, it is preferable to assume values ​​stored in the electronic control unit. Preferably, these stored values ​​are those that have empirically proven to be average for road users with regard to the reaction time and braking force of the obstacle's driver.For the braking performance of the obstacle's braking system, a value is stored that is average for the vehicle fleet of the country on whose road network the procedure is to be used.

[0010] To reliably bring the vehicle to a standstill before a collision occurs, emergency braking is preferably carried out automatically with maximum brake pressure. This maximum brake pressure is maintained until the vehicle has come to a complete stop.

[0011] Emergency braking is suitable for avoiding collisions at low and medium speeds. At high speeds, such as those encountered on highways and freeways, accident data shows that collisions can be optimally avoided by changing lanes. Emergency braking often fails to significantly reduce the consequences of an accident. Therefore, this procedure is preferably used only when the vehicle is traveling at a maximum speed of 70 km / h, and particularly preferably only at a maximum speed of 60 km / h.

[0012] The computer program is configured to execute each step of the procedure when running on an electronic control unit. For this purpose, it is stored on a machine-readable storage medium.

[0013] By uploading the computer program to a conventional electronic control unit, an electronic control unit is obtained which is set up to perform an automatic emergency braking of a motor vehicle using the procedure. Short description of the drawings

[0014] Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. Fig. Figure 1 schematically shows an unnecessary emergency braking maneuver that can be avoided by means of exemplary embodiments of the method according to the invention. Fig. Figure 2 schematically shows the collision of a motor vehicle with another road user due to an emergency braking event triggered by a ghost object, which can be avoided by means of exemplary embodiments of the method according to the invention. Fig. Figure 3 schematically shows another collision of a motor vehicle with another road user due to an emergency braking triggered by a ghost object, which can be avoided by means of exemplary embodiments of the method according to the invention. Fig. Figure 4 schematically shows the assessment of a potentially imminent collision between a motor vehicle and an obstacle in a method according to an embodiment of the invention. Fig. Figure 5 schematically shows a motor vehicle whose automatic emergency braking can be triggered by a method according to an embodiment of the invention. Fig. Figure 6 shows a flowchart of an embodiment of the method according to the invention. Embodiments of the invention

[0015] State-of-the-art driver assistance systems are designed to bring a motor vehicle to a standstill at an early stage in the event of an imminent collision with an obstacle, or to reduce its speed to such an extent that a collision is thereby avoided. Fig. Figure 1 shows how the path 11 of a motor vehicle 10 intersects the path 21 of another motor vehicle, which may represent a potential obstacle 20 for the first motor vehicle 10. The driver assistance system of the motor vehicle 10 triggers automatic emergency braking, which brings the motor vehicle 10 to a standstill or reduces its speed sufficiently early to ensure that a safety distance a remains at all times between its front 12 and the edge 22 of the path 21 of the obstacle 20 facing the motor vehicle 10. In the Fig. In the situation depicted in Figure 1, the driver of the second vehicle recognized the impending collision and braked to avoid it. By the time the first vehicle (10) came to a stop, the potential obstacle (20) had already stopped before the possible point of collision. The emergency braking was therefore unnecessary.

[0016] While the unnecessary emergency braking, which in Fig. As depicted in 1, which is merely unpleasant for the driver of motor vehicle 10, is shown in Fig. Figure 2 depicts a dangerous situation for the driver. The driver of vehicle 10 is attempting to turn left at an intersection. Due to the reflection of radar waves from a radar sensor of vehicle 10 off surrounding infrastructure elements, its driver assistance system incorrectly assumes the presence of another vehicle, which is interpreted as a potential obstacle 20. The path of this other vehicle 21 intersects the path 11 of vehicle 10. An emergency braking maneuver is initiated, which brings vehicle 10 to a stop at a collision point k in the middle of the intersection. There, it collides with an oncoming third vehicle 30, whose path 31 intersects the path 11 of vehicle 10. This would have been unproblematic if the first vehicle 10 had continued immediately, but as a result of the emergency braking, it leads to a collision.

[0017] An even more dangerous situation exists in Fig. Figure 3 shows that the vehicle 10 came to a standstill due to emergency braking because its radar sensor mistakenly identified a ghost object as an obstacle 20 whose path 21 would intersect the path of the vehicle 10. As a result, the vehicle 10 entered the path 31 of another vehicle 30 approaching from the left, leading to a life-threatening collision on the driver's side. The impact of the vehicle 30 approaching from the left struck the passenger compartment of the vehicle 10, posing a risk of serious or life-threatening injury to the vehicle occupants.

[0018] To minimize the risk of such unnecessary and potentially dangerous collisions, one embodiment of the method according to the invention provides that, before initiating automatic emergency braking, it is first assessed whether a motor vehicle, which presents itself as a potential obstacle 20, could still avoid the potential collision independently through driving intervention by its driver. This reduces the risk of such collisions. Fig. The unnecessary emergency braking shown in point 1 was avoided. When ghost objects appear, as in... Fig. 2 and Fig. As shown in Figure 3, the emergency braking would be delayed for so long that the ghost objects could be identified as such with a high degree of probability, thus preventing the emergency braking from occurring. For this purpose, it is assessed whether the obstacle 20 is still in a first zone 41 on its path 21, where it could still avoid the potential collision by braking, or whether it is already in a zone 42 where this type of collision avoidance is no longer possible. For this purpose, a safety distance s is added to the braking distance b of the obstacle 20. As soon as the predicted path 21, starting from the front of the obstacle 20 and consisting of the sum of braking distance b and safety distance s, intersects the path 11 of the vehicle, the emergency braking of the vehicle 10 is triggered, provided that all other necessary conditions for triggering the braking are still met.For this prediction, cooperative behavior from the driver of the obstacle 20 is assumed. To estimate the braking distance b, typical values ​​for a driver's reaction time, braking force, and the braking performance of a motor vehicle's braking system are assumed.

[0019] In order to carry out the method according to the invention, the motor vehicle 10 has, as shown in Fig. Figure 5 shows a detection system 13 arranged on the front of the vehicle. In the present embodiment, this system comprises at least one radar sensor. The detection system is connected to an electronic control unit 14 of the vehicle 10. The electronic control unit 14 also controls the vehicle's braking system (not shown) and can thus trigger automatic emergency braking.

[0020] The sequence of an embodiment of the method according to the invention is described in Fig.Figure 6 illustrates this. A start 50 of the procedure is initiated when the motor vehicle 10 is traveling at a maximum speed of 70 km / h. Based on input data from the detection system 13, the electronic control unit 14 then performs an assessment 51 to determine whether a collision with an obstacle 20 is imminent, where the obstacle 20 is a moving obstacle, and whether the driver of the obstacle 20 could still avoid the collision by braking. If an initial check 52 indicates that there is no risk of collision, the procedure is terminated 55. Otherwise, a second check 53 is performed to determine whether the collision with the obstacle can still be averted by the driver of the obstacle by braking. As long as this condition is met, the monitoring and assessment of the traffic situation in step 51 continues with the two subsequent checks 52 and 53.However, if the second test 53 reveals that the driver of the obstacle can no longer avert the impending collision, an emergency braking action 54 of the motor vehicle 10 is initiated and the procedure is subsequently terminated 55. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 197 38 611 A1

[0003]

Claims

[1] Method for automatic emergency braking (54) of a motor vehicle (10), in which a detection system (13) arranged on the motor vehicle (10) detects moving obstacles (20) and reports them to an electronic control unit (14) of the motor vehicle (10), characterized by that the automatic emergency braking (54) of the motor vehicle (10) is only triggered when an imminent collision of the motor vehicle (10) with an obstacle (20) is detected by the control unit (14), which collision can no longer be avoided by influencing the obstacle (20). [2] Method according to claim 1, characterized by that when the impending collision is detected, a cooperative behavior of the obstacle (20) is assumed. [3] Method according to claim 1 or 2, characterized by that the driving influence is a braking maneuver. [4] Method according to claim 3, characterized bythat when the impending collision is detected, a predeterminable safety distance (s) is added to a braking distance (b) of the obstacle (20). [5] Method according to claim 3 or 4, characterized by that when the impending collision is detected, values ​​are assumed for a reaction time of a driver of the obstacle (20), a braking force of the driver of the obstacle (20) and a braking power of a braking system of the obstacle (20), which are stored in the electronic control unit (14). [6] Method according to one of claims 1 to 5, characterized by that the emergency braking (54) occurs with maximum brake pressure. [7] Method according to one of claims 1 to 6, characterized by that the method is only used when the speed of the motor vehicle (10) does not exceed 70 km / h. [8] A computer program arranged to carry out each step of the method according to any one of claims 1 to 7. [9] A machine-readable storage medium on which a computer program according to claim 8 is stored. [10] Electronic control unit (14) which is designed to carry out an automatic emergency braking (54) of a motor vehicle (10) by means of a method according to one of claims 1 to 7.

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