DE10335898A1 - Driver assistance system with means for detecting moving and stationary objects in front of the driver's vehicle, whereby evaluation of stationary objects is improved by accessing the behavior of moving objects - Google Patents

Abstract

The dvice for evaluating stationary objects (C) in a driver assistance system has an angular resolving ranging system for locating stationary and moving objects (C, B) and a tracking module for tracking the located objects. The tracking module has a recognition module that is designed to detect characteristic movement patterns of the moving objects relative to a stationary object that is to be accessed.

Description

The The invention relates to a device for the evaluation of standing Objects in a driver assistance system, which is an angle-resolving ranking system for locating and moving objects and a tracking module to track the located objects.

In Motor vehicles are increasingly being used in driver assistance systems, the driver in the lead of the motor vehicle. To capture the traffic environment is a ranking system, for example a radar or lidar system that emits electromagnetic waves and those in the environment, especially in the run-up to the vehicle existing Locate objects based on the waves reflected by these objects. From the duration of the reflection signals then the distance of the Objects are calculated. Furthermore Is it possible, e.g. based on the Doppler shift of the reflected signal the Relative speed of the object to measure, so that Comparison of the relative speed with the airspeed of the vehicle equipped with the assistance system between standing and movable objects can be distinguished. Because of a certain angular resolution the ranking system also able to at least roughly estimate whether a located object on the vehicle of its own vehicle Lane or on a side lane or on the roadside.

One A typical example of a driver assistance system is an ACC system (Adaptive cruise control), with which the airspeed up one chosen by the driver Desired speed is regulated, as long as the lane is clear, or, if a preceding vehicle is located, the airspeed adapted that will the vehicle ahead is tracked at a suitable safety distance becomes. These systems are especially for trips with relatively high Speed, for example, on highways, provided where in the generally not with standing obstacles on the road too is calculated. However, there are efforts to the scope of such Systems to complement a so-called LSF system (Low Speed Following), with the one ahead vehicle even at low speed, can be tracked for example in congestion traffic. These systems should In particular, also be able to own vehicle automatically to brake when the preceding vehicle stops, and under certain conditions also an automatic restart of the own vehicle to cause, if the front vehicle again starts up.

assistance systems with such advanced features must also be able to to react appropriately to standing objects. It turns out however, with difficulty, with the help of existing sensors with sufficient certainty to evaluate whether it really is a located object is a relevant obstacle, such as a stale one Vehicle or a vehicle involved in an accident, or if it's just a bogus obstacle, such as Radar reflections from a manhole cover or one lying on the road Tin can. Previous approaches to the solution This problem is aimed at an evaluation of the objects standing based on the detected Object size and / or to make the amplitude of the received radar echo.

Advantages of invention

The Invention having the features specified in claim 1 provides the Advantage that they a more reliable Classification of standing objects as real obstacles or apparent obstacles allows.

To The basic idea of the invention becomes the movement pattern for this purpose moving objects, such as vehicles in front, near of the standing object to be evaluated. For example when tracking a moving object with the help of the tracking module shows that this Dodge object to a stationary object, this indicates that it the standing object is a real obstacle. If on the other hand shows that the preceding vehicle "passes over" the located stationary object, it can be concluded that it is when the standing object is just a dummy obstacle. On This can be the reliability the valuation of standing objects are significantly increased.

advantageous Embodiments of the invention are specified in the subclaims.

The response of the driver assistance system to a stationary object that has been classified as a relevant obstacle may depend on the particular situation. At low speed, for example in LSF mode, the response may be to select the detected obstacle as the new target. This corresponds, for example, to the situation in which a preceding vehicle, which has hitherto been tracked as a target, makes a lane change in order to avoid the stationary obstacle. The LSF system would then select this obstacle as the new target and cause the own vehicle to come to a stop behind the obstacle at an appropriate distance, unless the driver of his own vehicle initiates an evasive maneuver. For example, at higher speeds, such as in ACC mode, where standing obstacles are usually ignored, the response to an obstacle detected due to an evasive maneuver may be to alert the driver to the detected obstacle. The warning may consist in an audible and / or visual warning signal or a takeover request, which causes the driver to take control himself. However, the warning can also exist, for example, in a "haptic" warning signal, such that the system automatically causes an applied braking intervention with a constant delay in order to alert the driver to the danger situation.

If on the other hand, the driver assistance system operated in a mode in which principle must react to standing obstacles, for example in the LSF mode, allows it's the invention, standing objects, even in their own lane, exceptionally, ignore it when approaching from a preceding Vehicle were run over and therefore classified as bogus obstacles.

The The classification of still objects described above is inherently particular important for objects that are in their own lane. However, it can be analogous to Objects performed on secondary tracks become. If e.g. a standing object on a secondary track due to a avoidance maneuver of a preceding vehicle is classified as a real obstacle a warning can be issued to the driver if the driver initiates a lane change on the lane on the the obstacle is located.

The System response to an object that has been classified as "relevant" may also be from it dependent how far this object is laterally opposite the center of its own lane is offset. For example, one recognized as a relevant obstacle Object, which is located approximately in the middle of its own lane, selected as a new target object be while only a warning is issued if the object near the edge of its own lane. In this case can already a lower sideways movement of the preceding vehicle are interpreted as an "evasive maneuver". The review of a stationary object can be combined with the transverse offset of this Object into a probability parameter, the the likelihood of it indicates that it if the standing object is a relevant obstacle, and then the further system reaction be true. Likewise, the Evaluation of stationary objects based on the movement patterns of preceding ones Vehicles can also be combined with other evaluation methods, for example, with a rating based on object size or the amplitude of the radar reflex. In this case, the Results of different evaluation methods with different Include weights in the probability parameters.

drawing

One embodiment The invention is illustrated in the drawings and in the following Description closer explained.

It demonstrate:

1 a block diagram of a driver assistance system with a device according to the invention for the evaluation of stationary obstacles;

2 a sketch illustrating the operation of the device in the evaluation of an object as a relevant obstacle;

3 and 4 a Grundrißskizze and a side view of a traffic situation to explain the operation of the device in the classification of an object as a dummy obstacle; and

5 and 6 Flow charts for explaining the operation of the device.

description of the embodiment

In 1 a driver assistance system of a motor vehicle is shown as a block diagram. The driver assistance system includes a ranking system 10 , For example, an angle-resolving radar sensor, which is installed at the front of the vehicle, and an electronic evaluation device 12 with multiple functional blocks, which may be implemented as specialized electronic circuits or as software modules in one or more microprocessors.

The ranking system 10 Transmits the distance, relative speed, and angle data of all stationary and moving objects located in the run-up to the vehicle to a block 14 , which makes a preclassification of the located objects. In the block 14 is determined for each object on the basis of the measured relative speed and on the basis of the intrinsic speed of this vehicle known by sensors aboard the own vehicle, whether it is a stationary object or a moving object, that is presumably a driving the vehicle ahead. In addition, in block 14 Based on the distance and angle data decided whether the object is on its own lane or outside its own lane.

In a known as such tracking module 16 then the moving objects become over the successive measuring cycles of the Rangingsystems 10 followed. In each new measurement cycle, the objects are identified by matching the location data with the objects that are already known from the previous measurement cycles. This tracking is performed both for vehicles in their own lane and for vehicles in the secondary lanes.

Accordingly, in a second tracking module 18 also tracks the standing objects. Due to the proper motion of the vehicle equipped with the assistance system, the location data of the stationary objects is subject to a change over time. For the sake of simplicity, it should be assumed here as an example that standing objects are only to be considered for further evaluation when they are in their own lane. Thus, the tracking procedure is limited to standing objects on its own lane.

The actual control functions of the driver assistance system are controlled by a controller 20 executed, the tracking data of vehicles ahead of the tracking module 16 be transmitted and calculated on the basis of this data, the necessary regulatory intervention in the drive system and / or the braking system of the vehicle. In the example shown, the controller 20 operable in two modes of operation, namely an ACC mode and an LSF mode. In ACC mode, when at least one moving object is in its own lane, the following is under the tracking module 16 tracked objects that object that is located on the own lane and has the smallest distance, so the immediately preceding vehicle, selected as the target object. This mode is only available above a certain minimum speed of, for example, 50 km / h and normally does not consider standing objects. In contrast, the LSF mode is available in the lower speed range, up to speed 0, and makes it possible to track a preceding vehicle even if this vehicle stops temporarily. Consequently, standing objects must also be considered in the LSF mode. Because of the ranking system 10 however, even stationary objects that are not real obstacles, such as manhole covers or other smaller radar targets on the roadway, need to assess the stationary objects located on their own lane to determine whether they are real obstacles or obstructions. This purpose is served by a recognition module 22 , whose operation will be explained in more detail below.

If, for example, in the case of a traffic jam, the previously tracked preceding vehicle stops and thus becomes a stationary object, this object can continue to be controlled by the tracking module 16 be identified for moving objects with the previously tracked vehicle. This object can therefore be directly classified as a relevant obstacle.

2 on the other hand illustrates a traffic situation in which a newly emergent standing object must be evaluated. The own vehicle equipped with the driver assistance system is in 2 denoted by A. So far, the controller has 20 This vehicle follows an immediately preceding vehicle B in the LSF mode. In front of the vehicle B is a stationary vehicle C, the example, as a result of the glitch is left and thus represents a real obstacle. The vehicle B deviates from this obstacle and therefore makes a lane change to the left secondary lane. This lane change or at least a significant sideways movement of the vehicle B is the Rangingsystem 10 of the vehicle A detected. At about the same time locates the Rangingsystem for the first time the vehicle C, which was previously hidden by the vehicle B. In order to decide whether the newly emerged vehicle C is a real obstacle or a fake obstacle, the recognition module uses 22 as a criterion that the vehicle B would avoid only a real obstacle, a dummy obstacle, however, not. The tracking module 16 registers that the vehicle B makes a lane change while it is just behind the vehicle C, ie, while being from the ranking system 10 measured distance d _{B is} smaller than the distance d _{C of} the newly located vehicle C. The tracking module 16 reports this information to the recognition module 22 , which then classifies the vehicle C as a real obstacle. In the further tracking of the vehicle B by the tracking module 16 confirms that the vehicle B passes the obstacle (vehicle C) on the secondary lane, as in 2 indicated by dashed lines.

Once the detection module 22 the vehicle C has detected as an obstacle, it causes the controller 20 to now select the vehicle C as the target object. This target remains selected as long as the vehicle B remains on the side lane and as long as the own vehicle A does not in turn make a lane change. If the vehicle B, however, cancel the lane change operation and return to the right lane before it Has passed vehicle C, then the vehicle B would be selected again as the target object.

When in the in 2 shown situation of the controller 20 in ACC mode, the stationary vehicle C would normally be ignored. To increase traffic safety, however, it is expedient, although in this case the tracking module 16 the lane change of the vehicle B to the controller 20 and to the recognition module 22 so as to sensitize the system for the stationary vehicle C. The information that a stationary vehicle, so an obstacle, is in its own lane, can then from the controller 20 For example, be used to output a warning to the driver via a man-machine interface, not shown.

3 and 4 illustrate a situation in which there are two bogus obstacles C1 and C2, for example two manhole covers, on the lane traveled by the vehicle A, other than the vehicle B tracked as the target. The dummy obstacle C1 is just run over by the rear end of the vehicle B, so that the Rangingsystem 10 of the vehicle A now in addition to a radar echo 24 from the vehicle B also a radar echo 26 from the obstruction C1 receives. The dummy obstacle C1 is classified as a stationary obstacle at the pre-classification, but is still in the LSF mode by the tracking module 18 tracked while the tracking module 16 tracked vehicle B. The tracking module 16 now reports to the detection module 22 that the vehicle B did not make a lane change, but is on the same lane as the dummy obstacle C1 while passing this dummy obstacle. The recognition module 22 then classifies the dummy obstacle C1 correctly as a non-relevant object, with the result that the dummy obstacle C1 is not selected as the target object, but the preceding vehicle B remains selected.

In 3 and 4 the second dummy obstacle C2 can not yet be located because it is still covered by the vehicle B. The time at which a bogus obstacle is located for the first time coincides with the time when vehicle B passes the bogus obstacle. Accordingly falls in the example 2 the time at which the vehicle C is first located, approximately at the time at which the lane change of the vehicle B is detected. In practice, however, it may happen that the stationary object is already located at a somewhat earlier or even later time. On the basis of in 5 and 6 The flow diagrams shown will now be an example of a robust evaluation method will be explained in the tracking module 16 and in the recognition module 22 is implemented and also tolerates temporal deviations of the considered events.

In the 5 The procedure shown is cyclic by the trackingmadul 16 executed to detect lane changes of vehicles driving ahead in their own lane, which could be an indication of an evasive maneuver and thus a relevant stationary object.

In Step S1 tracks moving targets in their own lane, So for example the vehicle B. However, it can also be several vehicles be followed. In step S2 it is checked whether in one of these vehicles a lane change has occurred. A "lane change" in this context is a transverse movement understood of the vehicle, which is so pronounced that they considered a conscious evasive maneuver can be.

If such a lane change is detected, then in step S3, the distance d _B measured at that time is stored to the vehicle B making the lane change. Similarly, the time T _{B is} stored at which the lane change takes place.

For the vehicles for which no lane change is detected, in step S4 the distance d _{B is set} to a predetermined maximum value dmax, which is preferably greater than the locating depth of the ranking system.

The data stored in step S3 remains stored for a certain time L. This time L may depend on the intrinsic speed of the vehicle A or possibly also on the speed of the lane-changing vehicle B and corresponds to a specific route of the vehicle in question. By choosing this route or the time L can be achieved so that the evasive maneuvers remain stored only as long as they can still be associated with a standing within this period emerging stationary object. When it is determined in step S5 that the difference between the current time T ₀ and the stored time T _{B is} greater than L, the stored data for the subject vehicle B is cleared in step S6. Otherwise, a return to step S1 takes place directly.

6 shows a procedure used by the detection module 22 is performed when a stagnant object is located and evaluated for its relevance. In step S10, the distance d _{C of} the object measured by the ranking system at the current time is read. In step S11 then those of the tracking module 16 tracked moving objects searched on whether one of these objects nor an evasive maneuver fed is chert. The distance d _B stored for this object in step S3 is compared with the distance the potential obstacle had at the time the lane change was detected. Since the own vehicle has moved on in the meantime with the speed V, this distance is given by d _C + V (T ₀ -T _B ). In this way, the evasive maneuver or lane change can still be considered even if the potential obstacle is located at a later time. If the query in step S11 leads to a positive result, this means that the in 2 illustrated situation and the standing object is classified as relevant in step S12.

Otherwise, it is checked in step S13 whether there is a moving object on its own lane which has not performed an evasive maneuver (d _B = dmax), and the current distance dact of this mobile object is selected with an appropriately selected interval [d _C -d1, d _C + d2]. If dact is in the interval between d _C - d1 and d _C + d2, it means that the in 4 situation shown, ie, that the stationary object is a dummy obstacle C1, which is run over by the vehicle B or was run over. If, as in 4 , the apparent obstacle C1 is first located just in the moment in which it is run over by the vehicle B, then dact = d _C applies. However, the query in step S13 also accounts for the possibility that the dummy obstacle will be located at a somewhat earlier time when it is d1 or less in front of the vehicle B, or at some later time when it is at d2 or less behind the vehicle Vehicle B is located.

If the condition checked in step S13 is satisfied, the still object is classified as irrelevant in step S14. Otherwise, this object is further classified as an indefinite object in step S15. Thereafter, a return is made to step S10, and the procedure described above is repeated. For example, if in 4 the second dummy obstacle C2 could already be located by the ranking system, then the procedure would be 6 repeated until the vehicle B has also crossed this obstacle and thus the dummy object C2 could be classified as irrelevant.

Claims (7)

Device for evaluating stationary objects (C, C1, C2) in a driver assistance system that uses an angular resolution system ( 10 ) for locating and moving objects (C, C1, C2, B) and a tracking module ( 16 . 18 ) for tracking the located objects, characterized by a recognition module ( 22 ) which is adapted to detect characteristic movement patterns of the movable objects (B) with respect to the standing object (C, C1, C2) to be evaluated. Device according to claim 1, characterized in that that this characteristic movement pattern is that the movable Object (B) an evasive maneuver executing, to avoid the standing object (C). Device according to Claim 2, characterized in that the driver assistance system has a function (LSF) which selects a vehicle located in front of its own vehicle (A) on the same lane as the target object and controls its own vehicle (A) in such a way that it controls a predetermined one Distance to the target object, even if the target object is standing or stopping, and that the recognition module ( 22 ) is adapted to cause the function (LSF) to select a stationary object located in the same lane as the target object when the recognition module ( 22 ) with respect to this object (C) detects the characteristic movement pattern of the movable object (B). Device according to one of claims 1 to 3, characterized that this characteristic movement patterns or one of the characteristic movement patterns It is that the movable object (B) passes over the stationary object (C1, C2). Device according to Claim 4, characterized in that the driver assistance system has a function (ACC) which normally reacts only to movable objects and not to stationary objects, and in that the recognition module ( 22 ) is adapted to cause the issuance of a warning signal when it detects an evasion maneuver of a moving object (B) with respect to a stationary object (C). Apparatus according to claim 5, characterized in that the warning signal is that the recognition module ( 22 ) causes the driver assistance system to a delay of the vehicle (A). Device according to claim 6, characterized in that that the delay of the vehicle (A) by engaging in the braking system of the vehicle in takes the form of a brief warning braking.