EP1853454A1 - Method for recognising an imminent overtake - Google Patents

Abstract

The invention relates to a method for recognising an imminent overtake consisting in measuring a distance d with respect to a preceding vehicle (26), in evaluating the relative speed v of said preceding vehicle and in determining the overtake imminence with the aid of an d- and v-dependent function f (d, v). The blinker activation and/or acceleration/deceleration of the related vehicle are advantageously taken into account.

Description

Procedure for detecting an imminent overtaking maneuver

State of the art

The invention relates to a method for detecting an imminent overtaking process.

Motor vehicles are increasingly being equipped with driver assistance systems which, with the aid of suitable sensors, for example with the aid of radar sensors, detect the environment of the driver's own vehicle and assist the driver in guiding the vehicle and / or warn against dangers. An example of such a driver assistance system is a so-called ACC (Adaptive Cruise Control) system, with which the speed of the vehicle is regulated to a desired speed selected by the driver and, if a preceding vehicle is on a lane traveled by the own vehicle, the distance is measured to the preceding vehicle using the radar sensor and automatically controlled by adjusting its own speed. Such a system Not only helps to improve ride comfort, but also to reduce the risk of accidents. If the driver wants to overtake the slower preceding vehicle, he can override the ACC system by pressing the accelerator pedal and then initiate an overtaking maneuver by changing lanes.

However, when driving on freeways or multi-lane highways lane change operations and especially overtaking a significant accident risk, for example because the driver misjudges the distance and / or speed of approaching in the fast lane from behind vehicle or because this vehicle is in the blind spot and therefore overlooked by the driver.

For this reason, driver assistance systems have been developed that support the driver in lane change operations and / or issue a warning signal when a safe lane change is not possible. Such systems, also referred to as lane change assistants or blind spot warning systems, typically include enhanced sensing, such as in the form of a back-space radar for monitoring the traffic on the fast lane and / or a blind spot or ultrasonic sensor for monitoring the blind spot. If the system recognizes that the driver wants to initiate a lane change procedure, and then results from the sensor data that a safe lane change is not possible, a warning signal is issued to the driver. However, the acceptance of such a system is dependent on the driver's intention to overtake being recognized with sufficient reliability, as frequent false warnings are perceived as a significant compromise on comfort and safety. Various methods are already known for detecting the intention of the driver to overtake.

A method that z. B. DE 35 00 152 Al, DE 36 22 091 Al and DE 296 20 357 Ul is described, based on the evaluation of the status of the direction indicator. It is assumed that the driver indicates his intention to overtake by setting the direction indicator. However, this method has only a limited reliability because on the one hand the setting of the direction indicator (the left turn signal) does not always have to point to an overtaking intent and on the other must also be expected with the possibility that the driver initiates the overtaking, without first the turn signal actuate.

Driver assistance systems are also known which have a video system as an additional sensor component with which lane markings can be detected and thus the position of the vehicle relative to the left and right lane boundaries or an approach of the vehicle to one of these lane boundaries can be detected. A typical application are assistance systems that can issue a lane departure warning if the driver does not keep the vehicle close to the center of their own lane. An approach to the left lane boundary can also be interpreted as an indication of a driver's intention to overtake in such systems. However, a disadvantage is the relatively high cost of the video sensors and the relatively high susceptibility to failure of such a sensor, which can lead to misinterpretations and thus false warnings or the absence of necessary warnings in particular in poor visibility conditions. DE 101 18 265 A1 describes a method in which the yaw rate of one's own vehicle is measured with the aid of a yaw rate sensor. In addition, the angular velocity of a preceding vehicle is measured with the aid of an angle-resolver locating sensor, for example a radar sensor. By comparing these data can then gain a statement about an upcoming lane change. However, during slow lane changes during high-speed driving on highways, the yaw rate that occurs is very small, so that due to measurement noise and / or limited sensor resolution, it is often not possible to achieve adequate measurement accuracy. In addition, in this method, too, situations may arise in which a lane change intent is erroneously concluded or an actual lane change intent is not recognized. An example is the situation that the driver of the own vehicle initiates a lane change process when entering a right turn. In this case, although a non-zero angular velocity of the preceding vehicle is measured, but can not be measured corresponding yaw rate of the own vehicle, because the driver does not follow the road curvature, but initially drives straight ahead to change to the left secondary lane.

Advantages of the invention

The inventive method with the features specified in claim makes it possible to reliably detect an imminent overtaking with relatively little effort sensor.

The method is based on an assessment of the behavior of the driver as he approaches a slower preceding vehicle. If the driver does not intend to overtake, he will reduce his speed even at a relatively large distance to the vehicle in front so that he does not drive too close to the preceding vehicle. If, on the other hand, he intends to overtake, he will not reduce the speed but, if necessary, even accelerate to thread himself into the flowing traffic on the secondary lane. By comparing the measured object distance with the

Relative speed, which can be measured directly by means of a radar system or can be optionally calculated by derivation of the measured distance over time, therefore, an overtaking intent of the driver can already be detected before the driver attaches to a lane change. If then a vehicle is in the blind spot or approaches in the fast lane a vehicle with high relative speed, a warning can be issued to the driver. Even if, in exceptional cases, the driver's behavior is misinterpreted once and a warning is issued even though the driver has no intention of overtaking, the warning is nevertheless not in vain, since it alerts the driver that he is about to be too close to the front Drive on vehicle. The method makes it possible to detect an overtaking intent even if the driver has not set the left turn signal. Conversely, in cases where the driver has operated the turn signal for other reasons, it can be recognized that there is no intention to overtake.

In the simplest case, only one distance-measuring sensor is required for carrying out the method, so that the method can also be implemented on vehicles which have only a very limited environment sensor system. In particular, the method is not dependent on the presence of a video system, which also avoids the sources of interference resulting from the use of such a system. The same applies with regard to other sensor components which have been used in the conventional methods, for example for measuring the yaw rate of the own vehicle, the angular velocity of the vehicle in front and the like.

On the other hand, methods according to the invention can also be combined with the conventional methods described above in order to achieve an even higher detection probability and reliability.

Advantageous embodiments of the method are specified in the subclaims. A driver assistance system for carrying out the method is the subject of the independent product claim.

In an expedient embodiment, the quotient v / d is formed from the relative velocity v of the preceding vehicle and the measured distance d of this vehicle. This quotient or other suitable function of quantities v and d (or v / d), which is generally increasing in v and decreasing in d, then provides a measure of the likelihood that there will be an overtaking intent. If this probability is above a predefined threshold value, which may also be varied depending on the situation, it is decided that the driver intends to change lanes, and a warning is issued if the lane change is not possible without danger.

The threshold may, for example, depend on whether the driver has actuated the direction indicator. Since the setting of the turn signal on its own is an indication of an intent to overtake the driver, it is expedient to reduce the threshold, since only a small additional indication of the existence of an overtaking intent is needed. Similarly, the results of other known systems for recognizing lane change intent may also be included in the threshold, and on the other hand, it is also possible to obtain the ones obtained from variables v and d

To summarize the likelihood of the overtaking intention with the probabilities obtained by other methods into a total probability, which is then subjected to a threshold comparison.

drawing

An embodiment of the invention is illustrated in the drawings and explained in more detail in the following description.

Show it: Figure 1 is a sketch of a motor vehicle with a drawn as a block diagram driver assistance system;

Figure 2 is a sketch of a traffic situation for

Explanation of the method of the invention; and

Figures 3 to 5 are diagrams for explaining the operation of the method.

Description of the embodiment

1 shows a motor vehicle 10 is shown schematically, which is equipped with a driver assistance system that meets, for example, the functions of an ACC system (adaptive cruise control) and the function of a lane change assistant. As sensor components, an angle-resolving radar sensor 12, which is installed in the front of the vehicle and monitors the apron of the vehicle, a rear-space radar 14 for monitoring the rear traffic in the fast lane and an ultrasonic sensor 16 are provided with the particular vehicles can be detected in the fast lane, the are located in the blind spot between the rearview mirror, outside mirror and field of view of the driver and outside the detection ranges of the radar sensors 12, 14. The signals of these sensor components are evaluated in an electronic control unit 18, and a warning signal generator 20, for example an acoustic signal generator, is caused by the control unit 18 to output a warning signal when an overtaking intent of the driver has been detected and results from the signals of the sensors 14, 16 that a safe lane change to the left secondary lane is currently not possible.

This warning function requires that a lane change or overtaking intention of the driver can be detected with sufficient reliability. For this purpose, the method described in detail below is used.

FIG. 2 illustrates a typical traffic situation in which the vehicle-equipped vehicle 10 on the right-hand lane 22 of a multi-lane roadway 24 approaches a slower-ahead vehicle 26. With the help of the radar sensor 12, the distance d between the vehicles 10 and 26 is measured, as is the relative speed v of the vehicle 26 relative to the vehicle 10. Due to the angular resolution of the radar sensor 12, it is also possible to recognize that the vehicle 26 on the also located on the vehicle 10 right lane 22 is located.

The implemented in the control unit 18

Data processing system must now recognize whether the driver of the vehicle 10 intends to overtake the vehicle 26, or wants to reduce his speed to follow the vehicle 26 at an appropriate distance. If in this situation the ACC system is active, this system will automatically cause the vehicle 10 to adjust the speed, but the driver has the option of overriding the system by depressing the accelerator pedal. However, this does not necessarily mean that the driver really has the intention to overtake the vehicle 26. In FIG. 2, an arrow 28 indicates the course which the driver of the vehicle 10 intends to follow. Thus, the driver plans to change to the left lane 30 to overtake the vehicle 26.

FIG. 3 shows how the distance d changes as a function of the time t during this process. For the sake of simplicity, it is assumed that the vehicles 10 and 26 maintain their absolute velocity, so that the relative velocity v is constant over time, as shown in FIG. The distance d thus decreases linearly with time.

In FIG. 5, the quotient v / d is plotted against time t. This quotient is represented by a progressively rising curve that exceeds a predetermined threshold value S at a specific time tθ.

The threshold value S is selected, for example on the basis of empirical surveys, such that with an average driver up to the point in time tθ there is even greater probability that the driver does not want to overtake but instead still reduces his speed in order to follow the vehicle 26 , while after exceeding the threshold value S at time tθ is assumed that the driver intends to overtake. On the basis of this simple criterion, a passing desire of the driver can thus be recognized so that, if necessary, a warning signal can be output with the aid of the warning signal generator 20.

Instead of the quotient v / d, it is also possible to use another suitable variable for the threshold, which is a function the relative velocity v and the distance d. If the driver's desire to overtake is detected by exceeding the threshold S, this function should be such that it increases with increasing v and decreasing d.

Mathematically equivalent to this is the consideration of a function that falls with increasing v and decreasing d, such as the quotient d / v, if the decision criterion is that it falls below a suitable threshold.

According to a further development, a function may be considered which additionally depends on the positive or negative acceleration of the vehicle 10.

The quotient v / d used here can be interpreted physically as the time that would pass until the collision with the vehicle 26, when both vehicles 10, 26 continue their journey with unchanged speed.

Claims

claims 1. A method for detecting an imminent overtaking process, characterized by the following steps: Measuring the distance d to a preceding vehicle (26), Determining the relative velocity v of the preceding vehicle and Deciding whether an overtaking is imminent, based on the value of a function f (d, v) dependent on d and v. 2. The method according to claim 1, characterized in that it is decided that an overtaking process is imminent when the function f (d, v) exceeds a predetermined threshold value (S). 3. The method according to claim 2, characterized in that the function f is a monotone increasing function de quotient v / d. 4. The method according to claim 3, characterized in that the function f is proportional to the quotient v / d. 5. The method according to any one of claims 2 to 4, characterized in that the threshold value (S) is varied depending on the situation. 6. driver assistance system for motor vehicles (10), with at least one distance-measuring sensor (12) for detecting the traffic environment and a control unit (18) for performing an assistance function, characterized in that the control unit (18) for performing the method according to one of claims 1 to 5 is formed.