Lane change assist for motor vehicles

Abstract

Lane change assistant for motor vehicles, comprising a sensor system (10) for locating vehicles (28) on adjacent lanes (22, 32) in the rear of the own vehicle (24), a decision module (12) for deciding whether a vehicle (28) located in the rear is on an immediate adjacent lane (22), a driver interface (14) for outputting the decision result and a determination module (16) for determining the lane (20; ) being traveled by the own vehicle (24).22) is present, characterized in that the decision module (12) is configured to make the decision depending on the result of the determination module (16), that the determination module is configured to recognize a situation in which there is exactly one secondary lane (22) to the left of the vehicle (24), and that the decision module (12) is configured in this situation, in cases where it is not clear from the data of the sensor system (10) whether the located vehicle (28) is on the immediate secondary lane (22) or on a secondary lane beyond that, to decide that the located vehicle (28) is on the immediate secondary lane (22).

Description

State of the art

[0001] The invention relates to a lane change assistant for motor vehicles, comprising a sensor system for locating vehicles on adjacent lanes in the rear of the vehicle, a decision module for deciding whether a vehicle located in the rear is on an immediate adjacent lane, a driver interface for outputting the decision result, and a determination module for determining the lane being traveled by the vehicle.

[0002] Lane change assistants are designed to prevent drivers from pulling out into a secondary lane when an overtaking vehicle is approaching from behind, thus avoiding a collision risk or at least obstructing the overtaking vehicle. These systems typically use a rear-view radar, a radar sensor facing rearward or diagonally rearward, capable of measuring the distances, relative speeds, and azimuth angles of detected vehicles. From the distance and azimuth angle, the system calculates the vehicle's lateral displacement and thus determines its lane position. Furthermore, based on the distance and relative speed, it calculates whether a lane change is still possible without endangering following traffic.If the decision module determines that a lane change is not possible, and if it is also apparent, for example from the state of the turn signal or the driver's steering actions, that the driver intends to change lanes, a warning message is issued to the driver via the driver interface. This warning message can be in the form of a visual, audible, or haptic signal. A visual signal is particularly useful when displayed by a device integrated into the relevant exterior mirror of the vehicle.

[0003] With regard to road safety and system acceptance, the lane change assistant should be designed to avoid unnecessary false warnings while reliably issuing a warning in genuine hazardous situations. This requires a reliable determination of whether the detected vehicle is actually in the immediate left-hand lane (in countries with right-hand traffic). This determination is difficult because the sensor system's location signals are subject to certain error tolerances. Furthermore, unless the vehicle is equipped with a video system with electronic image processing capabilities that can directly detect lane markings on the road, the situation is complicated by the fact that the lane widths are not precisely known and can only be estimated.This can lead to ambiguities where it is unclear whether the located vehicle is in the left-hand lane but is moving relatively far to the right within that lane, or whether the vehicle is in its own lane and is moving relatively far to the left of its own lane. Similar ambiguities arise when assigning the located vehicle to the immediate adjacent lane or the next-but-one adjacent lane. The decision is further complicated on curved roads. To resolve this latter problem, US 2003 / 0025597A1 proposes recording the history of the road's alignment.

[0004] From DE 103 27 869 A1, a lane change assistant according to the preamble of claim 1 is known, which is combined with a navigation system. The determination module checks whether the driver has positioned themselves correctly when the navigation data indicates that a turning maneuver is imminent. Disclosure of the invention

[0005] The purpose of the invention is to further improve the reliability of the lane change assistant.

[0006] This problem is solved according to the invention with the features specified in claim 1 by the fact that the decision module is configured to make the decision depending on the result of the determination module. The determination module is capable of recognizing a situation in which there is exactly one adjacent lane to the left of the vehicle. Furthermore, in this situation, the decision module is configured to decide, in cases where it is unclear from the sensor system data whether the located vehicle is in the immediate adjacent lane or in the next adjacent lane, that the located vehicle is in the immediate adjacent lane.

[0007] It has been shown that the frequency of false warnings can be significantly reduced, and conversely, the omission of necessary warnings can be avoided in many cases, if the lane of a multi-lane roadway in which the vehicle is located is known and taken into account in the decision module. For example, if the vehicle is in the second lane from the left, there is no adjacent lane beyond that. This means that vehicles located relatively far to the left of the vehicle must be in the immediately adjacent lane. Advantageous embodiments of the invention are specified in the dependent claims.

[0008] An example of a device that makes it possible to determine the lane being traveled by one's own vehicle is described in DE 103 45 802 A1. However, within the scope of the invention, any known and suitable device can be used for this purpose.

[0009] If the vehicle is equipped with a video system for monitoring the area in front of it, its data can be used to determine the vehicle's lane. In practice, vehicles equipped with a lane change assistant usually also have an adaptive cruise control (ACC) system. This system uses a forward-facing radar sensor to monitor the area in front of the vehicle and to locate vehicles ahead, automatically adjusting the distance between the vehicle and the vehicle immediately in front. In this case, statistical analysis of the lateral displacements of vehicles ahead, overtaking, and overtaken vehicles can determine how many lanes are present and in which lane the vehicle is located. Alternatively or additionally, data from the rear-view radar can also be used for such statistical analysis.If the vehicle is equipped with an advanced navigation system whose digital map contains information about the number of lanes on the road, at least the total number of lanes in the direction of travel can be determined using the navigation system. With sufficient spatial resolution of the associated GPS system and sufficient accuracy of the digital map, the navigation system can also directly determine the vehicle's own lane.

[0010] Since radar sensors, such as ACC radar or rear-view radar, can also measure the relative speeds of detected objects, stationary objects at the roadside, such as guardrail posts, can be identified, thus providing information about the total width of the roadway. If the number of lanes is also known, the width of an individual lane can then be calculated with relatively high accuracy. This information, in turn, helps to assign vehicles detected in the rear to the different lanes with greater reliability. This improves the accuracy of the decision module, particularly in situations where two or more left-hand lanes are present.

[0011] In this description and also in the patent claims, the terms "left" and "right" consistently refer to countries with right-hand traffic. For countries with left-hand traffic, these terms should be interchanged. Brief description of the drawings

[0012] An embodiment of the invention is shown in the drawings and explained in more detail in the following description.

[0013] They show: Fig. 1 a block diagram of a lane change assistant according to the invention; and Fig. 2 to Fig. 4 sketches to illustrate how the lane change assistant works in different traffic situations. embodiment of the invention

[0014] The in Fig. The lane change assistant shown comprises a sensor system 10, for example a rear-view radar, for locating vehicles and other objects in the rear of the vehicle, a decision module 12 for deciding whether a vehicle located by the rear-view radar is in the immediate left-hand lane or another lane, and a driver interface 14 for issuing a warning to the driver depending on the decision result of the decision module 12.

[0015] As is typical for lane change assistants, the decision made by decision module 12 depends not only on the lane assignment of the detected vehicle, but also on the measured distance and relative speed of that vehicle. A warning message will generally only be issued to the driver if, based on the traffic situation or driver actions such as activating the turn signal, steering maneuvers, and the like, it is apparent that the driver intends to change lanes. Devices for detecting such a lane change intention by the driver are known and will not be described in detail here. Decision module 12, which processes the various pieces of information and generates the command to issue the warning message, is implemented in a known manner by an electronic data processing system with suitable software.

[0016] The lane change assistant according to the invention additionally includes a determination module 16, which serves to determine, using known methods, in which lane of a multi-lane carriageway the vehicle is located. This information is provided to the decision module 12 and evaluated there, as shown below. Fig. 2, Fig. 3 to Fig. 4 will be explained.

[0017] Fig. Figure 2 shows a two-lane carriageway 18 with a right lane 20 and a left lane 22. The vehicle's own lane, equipped with the lane change assistant, is located... Fig. Vehicle 24, equipped with ACC, is driving in the far left lane 22. The sensor system 10 on vehicle 24 is symbolized by two rear-view radar sensors. An ACC radar sensor 26, which monitors the area in front of vehicle 24, is also indicated.

[0018] Vehicle 28 is following vehicle 24 in the left lane 22, approaching at a higher speed. The speeds of the vehicles are symbolized by arrows. Vehicle 28 is traveling slightly to the left of vehicle 24. Based solely on the data from sensor system 10, it is therefore not immediately clear whether vehicle 28 is in the same lane as vehicle 24 or in a left-hand lane. If it were in a left-hand lane, there would be an acute risk of collision due to vehicle 28's high speed. Furthermore, if there is evidence of the driver's intention to change lanes, for example, because the driver has activated the left turn signal for any reason, a warning message to the driver would be required.

[0019] However, the determination module 16 provides the decision module 12 with the information that its own vehicle 24 is already in the far left lane 22 and therefore there is neither a possibility for the driver of its own vehicle 24 to change lanes to the left nor a possibility for vehicle 28 to overtake. In this situation, the decision module 12 can therefore decide with certainty that vehicles 24 and 28 are in the same lane and thus no warning is issued to the driver.

[0020] The in Fig. The illustrated situation 3 differs from the situation described below. Fig. 2. Initially, the warning is triggered by the fact that the driver's own vehicle 24 is now located in the right lane 20. Furthermore, the following vehicle 28 is driving close to the left edge of the left lane 22. Without knowledge of the lane configuration, it would therefore be possible that vehicle 28 is located in a (non-existent) left-hand adjacent lane, meaning there would be no risk of collision from this vehicle. However, based on the data from the determination module 16, it is clear that the driver's own vehicle 24 is located in the right lane of the two-lane carriageway 18, i.e., the second lane from the left, and that therefore there is no left-hand adjacent lane. Consequently, vehicle 28 must be located in the immediate left-hand adjacent lane 22, and a warning must therefore be issued to the driver.

[0021] Fig. 4 illustrates the same situation as Fig. 3, with the only difference being that the vehicles here are traveling on a carriageway 30 with three lanes, i.e., the left-hand secondary lane 22 from the perspective of vehicle 24 is the middle lane of the carriageway, and there is also an outermost left-hand lane 32. Since vehicle 28 is traveling significantly offset to the left on lane 22, it is not possible to definitively determine from the data of sensor system 10 whether this vehicle is on the immediate left-hand secondary lane 22 or on the outermost left-hand lane 32. The information provided by the determination module 16 that lane 32 exists at least allows for the possibility that vehicle 28 could be on this lane 32 and that no warning message would need to be issued to the driver. However, this does not eliminate the ambiguity of the situation, and additional information would be required to make a reliable decision.

[0022] However, the information provided by decision module 16 regarding the total number of available lanes offers the possibility of obtaining such additional information. In Fig.Stationary guardrail posts 34 are indicated at the left and right edges of the roadway. The ACC radar sensor 26 can not only locate these guardrail posts 34, but also, by measuring their relative speed, determine that their absolute speed is zero, meaning they are stationary objects and therefore must be located outside the carriageway 30. The regular grid pattern in which these guardrail posts 34 are typically arranged provides additional evidence. By measuring the lateral offset of the left and right guardrail posts 34 using the ACC radar sensor 26, or alternatively, the rear-view radar, the total width of the carriageway 30 can be determined with good approximation. Dividing this total width by the known number of lanes yields a relatively reliable measure of the width of each lane.While the lane width determined in this way may still be subject to error, it is certainly more accurate than a mere estimate. Based on this information, it is therefore possible to more reliably decide whether vehicle 28 is located in the immediately left-hand lane 22 or in the second-next lane 32.

[0023] In the example shown, the result is that vehicle 28 is located in the immediate left-hand lane 22, and a warning is correctly issued. If, however, vehicle 28 were driving close to the right edge of the far left lane 32, an unwanted false warning would be avoided due to the more precise knowledge of the lane width.

Claims

[1] Lane change assistant for motor vehicles, comprising a sensor system (10) for locating vehicles (28) on adjacent lanes (22, 32) in the rear area of ​​the own vehicle (24), a decision module (12) for deciding whether a vehicle (28) located in the rear area is on an immediate adjacent lane (22), a driver interface (14) for outputting the decision result and a determination module (16) for determining the lane (20, 22) being traveled by the own vehicle (24), characterized by, the decision module (12) is trained to make the decision depending on the result of the determination module (16), that the determination module is trained to recognize a situation in which there is exactly one secondary lane (22) to the left of the own vehicle (24), and that the decision module (12) is trained in this situation, in cases in which it is not clear from the data of the sensor system (10) whether the located vehicle (28) is on the immediate secondary lane (22) or on a secondary lane beyond that, to decide that the located vehicle (28) is on the immediate secondary lane (22). [2] Lane change assistant according to claim 1, characterized by, that the determination module (16) is designed to recognize a situation in which the own vehicle (24) is located on the outermost left lane (22) of a carriageway (18) in a direction, so that a located vehicle (28) cannot be located on a left-hand side lane. [3] Lane change assistant according to one of the preceding claims, characterized by , that a sensor device (26) is provided for measuring the total width of the carriageway (30) travelled by the vehicle (24) and that the decision module (12) is designed to calculate the width of a single lane of this carriageway based on this total width and the number of lanes of the carriageway (30) determined by the determination module (16).

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