WO2006122867A1 - Lane change assistant for motor vehicles - Google Patents

Abstract

The invention relates to a lane change assistant for motor vehicles, which comprises a monitoring device for monitoring the traffic in the space ahead and behind the own vehicle (26) and a decision device for deciding whether a safe lane change is possible. The lane change assistant is characterized by a recommendation device (16) that is adapted to calculate the temporal development of vehicle distances in advance and to output a recommendation (40) for a lane change when a safe lane change is possible and when the distance to a vehicle (32) ahead on the own lane (28) is smaller than a predetermined minimum distance within a predetermined period.

Description

Lane change assistant for motor vehicles

State of the art

The invention relates to a lane change assistant for motor vehicles, with a monitoring device for monitoring traffic upstream and in the back of the own vehicle and a decision device for deciding whether a safe lane change is possible.

DE 199 37 489 A1 describes a lane change assistant in which the apron and the rear space of the vehicle are monitored by video systems. By electronic image analysis then the traffic situation as well

Road markings and no-sign signs are automatically detected. If the driver makes preparations for a lane change, in particular to overtake, although the traffic situation does not allow this or there is a passing ban, the driver is warned by the system. Furthermore, the possibility is indicated in this document, the lane change assistant directly to the drive system, the

To let brake system and the steering of the vehicle to act in order to realize an "autopilot". However, the criteria for such interventions in vehicle management are not specified and it remains unclear how the road safety requirement should be met.

In practice, it is often observed that on highways, especially on three lanes

Motorways, the extreme right lane of passenger traffic is hardly used, with the result that the traffic capacity of the highway is not fully utilized and it comes to congestion on the left or the left lanes. A major cause for this Phenomenon can be seen in the fact that many drivers feel overwhelmed when they are in high traffic density from the extreme right lane to the fast lane, for example, to overtake a truck.

In fact, this maneuver to the driver does not make small demands. Not only does he have to correctly estimate the distance and the relative speed of the vehicle traveling in front, but at the same time also in the rearview mirror

Keep track of adjacent traffic on the secondary lane and also estimate the distance and relative speed of a vehicle approaching in the fast lane. Frequently the driver hesitates too long in this situation, so he misses the time window for threading in the traffic in the fast lane. In order not to drive too close to the front vehicle, the driver is forced to

Speed, which makes the transition to the fast lane all the more difficult and dangerous. To avoid this unpleasant situation, many drivers prefer to stay in the fast lane.

Advantages of the invention

The invention having the features specified in claims 1 and 3 gives the

Driver in the above situation, an aid and thus helps to increase driving safety and at the same time to improve the flow of traffic.

In the solution according to claim 1, the driver receives a decision support for a forward-looking, timely change to the fast lane. It is not waited until the driver indicates an overtaking intent or until the

Minimum distance to the preceding slower vehicle is reached, but the lane change assistant takes even the initiative and suggests the driver in good time before a change to the fast lane.

The solution according to claim 3, which can be suitably combined with the solution according to claim 1, concerns the reverse case that the driver is already on the fast lane is located. In this case, the driver is proposed to change to the slower lane, in right-hand drive countries, when the lane is clear, especially when approaching a faster vehicle in the fast lane from behind.

Advantageous developments and refinements of the invention emerge from the subclaims.

For monitoring the traffic environment, radar sensors can be used, as they are already in use in Adaptive Cruise Control (ACC) systems. Preferably, angle-resolving radar sensors are used, which allow a correct assignment of the located vehicles to the various lanes of the road. Alternatively or additionally, it is also possible to use video systems which then also make possible various developments of the system, for example an automatic detection of lane boundaries and a lane departure warning or an automatic lane keeping function (LKS, Lane Keeping System) and, if appropriate, automatic recognition and evaluation of traffic signs.

The output of the lane change recommendation is preferably carried out with a

Signaling device, which can assume different states, so that the conditions for the lane change can be specified in more detail. It is expedient to have a visual indication of the lane change recommendation, for example in the form of an arrow, which points to the left or to the right depending on the direction of the recommended lane change. By different colors of the arrow can be specified whether a safe

Lane change is possible or not. Thus, for example, a lane change recommendation could be symbolized by a green arrow, while a red arrow indicates that a lane change should be omitted because a subsequent vehicle is in the blind spot or approaching so quickly that a hazard or at least a significant hindrance would occur , If the driver still to one

Lane change makes, for example, by setting the turn signal or by engaging in the steering, an audible warning can be issued in addition. - A -

When a lane change recommendation by blinking the green arrow, the

Urgency of recommendation to be symbolized. For example, the flashing frequency can be increased as the time window for the safe lane change is shortened. By a color change, for example to yellow, can be symbolized that a safe lane change is only possible if at the same time the own vehicle is accelerated.

Particularly useful is a combination of the lane change assistant with an ACC system. If the driver reacts to a lane change recommendation, for example by setting the turn signal, the ACC system then intervenes in the longitudinal guidance of the vehicle in such a way that the vehicle optimally threads itself into the traffic on the secondary lane. In combination with a LKS system can then in another

Completion stage also a fully automatic implementation of the lane change operation can be implemented, including setting the turn signal.

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 block diagram of a lane change assistant according to the invention; and

Figures 2 to 8 sketches to explain the behavior of the lane change assistant in different traffic situations.

Description of the embodiment The lane change assistant shown in FIG. 1 comprises a monitoring device 10 for monitoring the traffic environment, a decision device 12 for deciding whether a safe lane change is possible, and a recommendation device 14 for outputting a lane change recommendation via a display 16. A further output of the recommendation device 14 is provided with a automatic vehicle longitudinal guidance system 18 (ACC).

The monitoring device 10 monitors the traffic ahead of the vehicle with the aid of an angle-resolving radar sensor 20 installed in the front of the vehicle. For monitoring the traffic at the rear, two further, preferably also angle-resolving, radar sensors 22 are provided. These are preferably installed in the vehicle, in particular, the traffic on the left and right

Can monitor secondary lane and also capture vehicles that are located on the side lane at a small distance to your own vehicle, and thus in the blind spot. At longer intervals, the locating ranges of the two radar sensors 22 should also jointly cover their own lane, so that even vehicles can be located that approach on their own lane.

In the monitoring device 10 is determined based on the location data of the radar sensors 20, 22, the lane, the located vehicles are each, and the distances and relative speeds of these vehicles are measured periodically and tracked, so that one obtains a largely complete picture of the current traffic situation.

With the decision device 12 is then decided in particular on the basis of the data of the radar sensors 22, whether a safe lane change to the right or left secondary lane is possible or not. For example, this is calculated for each located in the rear space on the secondary lane vehicle, how much this vehicle would have to delay, so that in the event of a lane change of the own vehicle, a collision is avoided or a reasonable safety margin can be met. If the calculated vehicle deceleration is above a certain amount Threshold, it is decided that a safe lane change is not possible, and this is displayed on the display 16.

In the following, it should be assumed as an example that applies in the field of application of the lane change assistant right-hand traffic. The current sense of traffic can be set on the system or, if necessary, automatically determined with the aid of a navigation system.

If the decision device 12 has determined that a change to the left secondary lane (fast lane) is possible, it is checked in the recommendation device 14 on the basis of the location data of the radar sensor 20 whether a lane change recommendation is to be output. This will be the case, for example, when a slower preceding vehicle is on its own lane while the fast lane is clear and, in addition, when it is foreseeable that the distance between the vehicle in front and the vehicle will continue at the same speed without changing lanes within a predetermined period of time x would decrease below the (speed-dependent) minimum distance required for safety reasons. The period of time x can be set by the driver and / or varied automatically depending on the number of lanes and / or the traffic density.

If, as in the example shown, the monitoring device 10 is based exclusively on radar sensors and not additionally on video sensors, it can be determined by statistical evaluation of the location data of the radar sensors (as can also take place for Kursprädiktion), how many lanes are present and on which lane your own vehicle is located. Of course, a recommendation for a change to the left side lane will only be issued if the vehicle is not already on the leftmost lane.

If the decision device 12 has determined that a lane change to the right is safely possible, and if the own vehicle is not already at the outermost is located on the right lane, the recommendation device 14 checks on the basis of the location data of the radar sensor 20, if the right secondary lane is free and a long-term driving at target speed allowed (or at least with a speed not less than the current lane), and they are then via the display 16 a recommendation for a lane change to the right.

If the driver responds to the lane change recommendation to the right or left by setting the corresponding direction indicator, this is signaled by a flashing state sensor 24 to the recommender 14, which then causes the longitudinal guidance system 18, the speed of the vehicle to the speed of the flowing traffic on the relevant Adjust secondary lane or to set speed.

The monitoring device 10, the decision device 12 and the recommendation device 14 as well as the longitudinal guidance system 18 are formed in practice by an electronic data processing system with one or more microcomputers and suitable software. The longitudinal guide system 18 can also directly in the context of the distance control on the data of

Monitoring device 10 and in particular the front radar sensor 20 access.

FIGS. 2 to 8 illustrate examples of the system behavior of the lane change assistant described above. In each case, a sketch of a traffic situation is shown in the left-hand part of the figure, and the corresponding display image on the display 16 is shown in the right-hand part.

In FIG. 2, a vehicle 26 equipped with the lane change assistant, hereinafter referred to as "own vehicle", travels on the far right lane 28 of a three lane roadway 30. Further ahead, on the lane 28, a slower vehicle 32 just leaves a vehicle 34 is overtaken on the middle lane 36 (fast lane). From behind, a faster vehicle 38 is approaching in the fast lane. The speed vectors of the vehicles are shown as arrows. The

Vehicle distances are shown shortened in relation to the real situation.

Since the own vehicle 26 is faster than the preceding vehicle 32, the distance between these vehicles in the foreseeable future will decrease to the recommended minimum distance. As a "minimum distance" is here the sake of simplicity, the target distance to be considered, the distance control by the longitudinal guide system

18 is underlying. The recommendation device 14 calculates how long it would take at unchanged speeds to reach the desired distance.

If this time period is smaller than the predetermined time period x of, for example, 5 s, the recommendation device 14 checks on the basis of the data of the decision device 12 whether a lane change to the left secondary lane, that is the middle lane 36, is possible. The distance between the vehicles 26 and 38 is so large and the speed difference between these vehicles is so small that the driver of the vehicle 38 needed only slightly delay to maintain the safety distance to the own vehicle 26. Thus, a safe lane change is possible. Accordingly, by the recommendation device 14 a

Lane change recommendation issued on the display 16. For this purpose, a green arrow 40 pointing to the left appears on the display 16.

Before issuing this lane change recommendation, the recommendation device 14 also checks the distance and the relative speed of the vehicle 34. If this vehicle 34 were slower than the vehicle 32, or if the distance to the vehicle 34 were already very small, the lane change recommendation would be omitted.

In Figure 3, the driver of the own vehicle 26 has not yet responded to the lane change recommendation, and the distance to the vehicle in front 32 has become smaller. Also, the vehicle 38 is further advanced, but is still so far away that a lane change is still possible. However, that has

Time window for the lane change shortened. This is indicated on the display 16 indicated that the arrow 40 is flashing. The smaller the time window, the higher the

Blink rate.

In FIG. 4, the vehicle 38 has approached further. A safe lane change is now only possible if the vehicle 26 is accelerated, among other things, because in the meantime the distance control has become active and the speed of the vehicle 26 has decreased. To a steady driving of the

To reach vehicle 26, the time period x should preferably be selected such that the first output of the lane change request takes place before the distance control has begun.

On the display 16 is indicated by a color change of the arrow 40 to yellow, that the time window begins to close and an acceleration of the vehicle 26 is required. If the driver now reacts to the lane change recommendation and sets the turn signal, the necessary acceleration of the vehicle 26 is automatically caused by the longitudinal guide system 18.

Figure 5 shows another situation in which the vehicle 38 has a much higher speed. A lane change of the vehicle 26 would therefore lead to a significant obstruction or even a risk to the driver of the vehicle 38. This is symbolized on the display 16 by a crossed-out red arrow 42. The same symbol would also appear if the vehicle 38 was slower but was already approximately level with the vehicle 26. Conveniently, the movement of the vehicle 38 through the

Decision device 12 extrapolated into the future, so that an approximate estimate of the position of the vehicle 38 is still possible even if this vehicle has already left the detection range of the radar sensor 22. In this way, virtually the blind spot between the detection areas of the radar sensors 22 and 20 is closed. Alternatively, the information of a blind spot sensor (e.g., Short

Range radar or video system) are used. In the situation shown in Figure 6 is the own vehicle 26 on the

Fast lane, while the vehicle 38 is approaching at high relative speed and just passing a vehicle 44. The decision device 12 checks on the basis of the location data for the vehicle 44, whether a lane change to the right secondary lane 28 'is safely possible. This condition is fulfilled here. If the right lane were free, the recommendation device 14 would immediately output a lane change recommendation to the right, symbolized on the display 16 by a green arrow 46 pointing to the right.

However, since in the present case the vehicle 32 is present, the recommendation device 14 additionally checks whether the spatial or temporal distance between the vehicles 26 and 32 is large enough. For example, it checks if the

Time gap between these vehicles is above a certain threshold.

In a more refined embodiment, the recommender 14 sets up the following calculations: First, it is calculated how much the vehicle 38 would have to decelerate if the own vehicle 26 remained in the fast lane. Furthermore, it is calculated on the basis of the distance and the relative speed of the vehicle 38, how long the overtaking of the vehicle 38 would take, if the own vehicle 26 would allow by a lane change to the right this overtaking. On the basis of the duration thus calculated, it is then calculated how much the own vehicle 26 would have to be decelerated so as not to drive too close to the vehicle 32. The lane change recommendation is output only when there is a predetermined relationship between the thus calculated delays for the vehicles 38 and 26, for example, when the vehicle 38 should be decelerated more than the vehicle 26.

Optionally, it may also be charged here that a considerate driver of the vehicle 38 would in turn accelerate to shorten the overtaking process. This is especially true when looking at the history of speed of the vehicle 38 shows that this vehicle was originally faster and his

Speed only temporarily adapted to that of your own vehicle.

In the event that no lane change recommendation is issued in Figure 6, because the vehicle 26 would delay significantly more than the vehicle 38, may be provided according to a development that the recommendation device 14 and an acceleration recommendation after acknowledgment by the driver

Issues acceleration command to the longitudinal guide system 18 so that the own vehicle 26, the vehicle 32 overhauled faster and then make the lane change to the right. If no ACC system is present, a signal, for example in the form of a yellow flashing light, may also be displayed on the display 16, prompting the driver to temporarily increase the speed. The

Lane change recommendation to the right is then issued as soon as the vehicle 32 has been overhauled.

FIG. 7 illustrates the situation in which the own vehicle 26 is just overtaking the vehicle 32 but has not yet completed the passing operation while the driver of the vehicle 38 is "urging". On the display 16 is then indicated by a crossed out, pointing to the right red arrow 48 that a lane change to the right is not yet possible.

FIG. 8 illustrates one possible embodiment in view of the frequently encountered situation that the traffic jams in the fast lane, so that the speed of the own vehicle 26 and a preceding vehicle 50 in the fast lane is barely greater than the speed of the vehicle 32 on the vehicle right lane. The driver of the vehicle 38 is approaching at high speed in the right lane and is apparently about to overtake on the right and then push into the safety distance between the vehicles 26 and 50. Also in this case, a lane change recommendation can be issued to the right, as long as that

Time window is still big enough. As a further criterion can be checked in this context, whether in the fast lane behind the own vehicle 26 still a another vehicle is located (not shown). If the distance of such a vehicle is small and / or the relative speed is high, the lane change request should be omitted.

Claims

claims 1. lane change assistant for motor vehicles, with a monitoring device (10) for monitoring the traffic in the run-up and in the back of the own vehicle (26) and a decision device (12) for deciding whether a safe Lane change is possible, characterized by a recommendation device (14) which is designed to predict the time development of vehicle distances and issue a recommendation for a lane change when this lane change is safely possible and when the distance to a vehicle in front (32) on the own track (28) within a predetermined period of time will be smaller than a predetermined minimum distance. 2.Tracking assistant according to claim 1, characterized in that the recommendation device (14) is adapted to additionally check before issuing a lane change recommendation to a passing lane (36), whether the fast lane in front of the own vehicle (26) is free. 3. lane change assistant according to the preamble of claim 1 or claim 1 or 2, characterized by a recommendation device (14) which is adapted to predict the temporal evolution of vehicle distances and a recommendation for a lane change from a passing lane (36) to a secondary lane (28 ') to spend when this lane change is safely possible and if no preceding vehicle is present on the secondary lane or the distance to such a vehicle (32) has a certain, preferably time-dependent minimum size. 4.Tracking assistant according to one of the preceding claims, characterized in that an output device (16) for the lane change recommendation is adapted to output a signal (42; 48) indicating that a safe lane change is not possible. 5. lane change assistant according to one of the preceding claims, characterized in that an output device (16) for the lane change recommendation is adapted to output a signal (40) which varies depending on the size of the still available for the lane change time window. ό.Tracking assistant according to claim 4 or 5, characterized in that the output device is a display (16) for outputting an optical signal (40; 42; 46; 48). 7.Tracking assistant according to one of the preceding claims, characterized in that the recommendation device (14) connected to a longitudinal guide system (18) of the vehicle and is adapted, in the case of a lane change recommendation to this longitudinal guidance system command to adjust the speed of the vehicle itself to the To spend speed on the future track. 8.Tracking Assistant according to claim 7, characterized in that the recommendation device (14) is adapted to receive a signal indicative of a lane change intention of the driver and to issue the command to the longitudinal guidance system (18) in response to this signal. 9.Tracking assistant according to one of the preceding claims, characterized in that it is adapted to pass through in combination with a Qureführungssystem (LKS) an autonomous lane change.