Longitudinally Guiding Driver Assistance System in a Motor Vehicle

Abstract

A longitudinally guiding driver assistance system in a motor vehicle includes a detection system for detecting currently applying events and relevant events lying ahead, which require an adaptation of the permissible maximum speed, and a function unit which, when detecting a relevant event, while taking into account the location of the relevant event lying ahead, determines a location-dependent point in time, whose reaching causes the function unit to initiate an output of prompt information for permitting an automatic adaptation of the currently permissible maximum speed to a new permissible maximum speed. The function unit is designed, in the case of an activation of the longitudinally guiding driver assistance system, while taking into account a detected currently applying event, to initiate a first output of prompt information for permitting an automatic first setting of the currently applying permissible maximum speed as the new permissible maximum speed.

Claims

1. A longitudinally guiding driver assistance system in a motor vehicle, comprising: a detection system that detects currently applying events and relevant events lying ahead, which require a change of a permissible maximum speed; and a function unit which, when detecting a relevant event, while taking into account a location of the relevant event lying ahead, determines a location-dependent point in time, a reaching of which causes the function unit to initiate an output of prompt information for permitting an automatic adaptation of a currently permissible maximum speed to a new permissible maximum speed, wherein the function unit is further designed, in a case of an activation of the longitudinally guiding driver assistance system, while taking into account a detected currently applying event, to initiate a first output of prompt information for permitting an automatic first setting of a currently applying permissible maximum speed as the new permissible maximum speed.

2. The longitudinally guiding driver assistance system according to claim 1, wherein the function unit is further designed to initiate the first output of the prompt information for permitting the automatic first setting of the currently applying permissible maximum speed as the new permissible maximum speed after a predefined time interval and/or route interval from the activation of the longitudinally guiding driver assistance system.

3. The longitudinally guiding driver assistance system according to claim 1, wherein the function unit is further designed to initiate the first output of the prompt information for the first-setting of the currently applying permissible maximum speed when activating the longitudinally guiding driver assistance system while taking into account a detected event lying ahead, which, after the permission of the first setting of the permissible maximum speed, would require an adaptation of the permissible maximum speed.

4. The longitudinally guiding driver assistance system according to claim 1, wherein the function unit is further designed to not initiate the first output of the prompt information for the first-setting of the currently applying permissible maximum speed during the activation of the longitudinally guiding driver assistance system when an event lying ahead is detected which competes with a current speed or with the permissible maximum speed after permitting the first setting.

5. The longitudinally guiding driver assistance system according to claim 4, wherein a competing event lying ahead is detected, if the competing event would require an adaptation of the maxim speed to anew maximum speed, which is lower than the permissible maximum speed after permitting the first setting, and/or the current speed is lower than the permissible maximum speed after permitting the first setting of the permissible maximum speed.

6. The longitudinally guiding driver assistance system according to claim 4, wherein the competing event lying ahead is detectable as a function of a permitted determined deceleration strategy for reaching the new permissible maximum speed determined based on the event lying ahead.

7. The longitudinally guiding driver assistance system according to claim 5, wherein the competing event lying ahead is detectable as a function of a permitted determined deceleration strategy for reaching the new permissible maximum speed determined based on the event lying ahead.

8. The longitudinally guiding driver assistance system according to claim 4, wherein the competing event lying ahead is detectable as a function of a permitted acceleration strategy for reaching the new permissible maximum speed determined based on the currently applicable event.

9. The longitudinally guiding driver assistance system according to claim 5, wherein the competing event lying ahead is detectable as a function of a permitted acceleration strategy for reaching the new permissible maximum speed determined based on the currently applicable event.

10. The longitudinally guiding driver assistance system according to claim 6, wherein the competing event lying ahead is detectable as a function of a permitted acceleration strategy for reaching the new permissible maximum speed determined based on the currently applicable event.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a schematic diagram of an exemplary construction of a longitudinally guiding driver assistance system designed as a speed control system in a motor vehicle, for controlling the speed to a desired speed; and

[0025] FIGS. 2A and 2B are views of a traffic situation and a corresponding graph, respectively, which influence the first output of prompt information for permitting an adaptation of the permitted maximum speed.

DETAILED DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 illustrates in detail, as a central element of a longitudinally guiding driver assistance system, a function unit FE. The function unit FE may be a microprocessor based function unit that carries out its functionality. The function unit FE receives input signals e1 of a detection system E, a speed signal v, a permission signal z for permitting an automatic adaptation of the permissible maximum speed, a rejection signal a for rejecting the permission of the automatic adaptation of the permissible maximum speed, and a signal +v for the manual adaptation of the permissible maximum speed.

[0027] The detection unit E is a map-based detection unit E which, by means of available map data, the own position and a known route section lying ahead, detects events that require an adaptation of the permissible maximum speed (such as the speed limit) or that permit it (such as the elimination of a speed limit). The map-based detection unit E is further developed such that, on the one hood, it detects the location of the current and relevant event lying ahead, thus also the amount of the maximally permitted limit speed applicable from this location, and transmits it to the function unit FE by signal e1.

[0028] The map-based detection unit E can further detect, by means of available map dataand, as required, while taking into account a planned driving route, available information concerning the course of the route, such as traffic circles, tight turns and/or turnoffs, and transmit the information to the function unit. From this information concerning the course of the route, relevant events can also be derived which require an adaptation of the permissible maximum speed.

[0029] Additionally, but not illustrated here, the function unit FE may be connected to a camera-based detection unit which, by means of the data of a forward-oriented sensor system (for example, a video sensor system), also detects speed-limiting events lying ahead, which may conceivably require an adaptation of the permissible maximum speed to anew maximum speed. In contrast to the map-based detection unit E, the camera-based detection unit can first detect the relevant locations on the basis of the sensor system only in an anticipatory fashion and only relatively quickly, orbecause of the required signal processingalso only after the passing of the relevant event.

[0030] As soon as relevant data e1 concerning the location of a relevant event lying ahead, the amount of the limit speed maximally permitted starting from this location and information concerning the currently permitted limit speed, are available to the function unit FE, the function unit FE can firsttaking into account a driver predefinitiondetermine the permissible maximum speed at the current location and at the location of the event lying ahead. As an alternative, the transmitted maximally permitted limit speed can be used directly as the permissible maximum speed.

[0031] By means of available additional relevant data, such as the relative speed difference between the vehicle and the determined new permissible maximum speed, the distance to the relevant location, the currently applying permissible maximum speed, information as to whether the vehicle is in a clear-travel mode at a currently applying permissible maximum speed or in a following-travel mode at a lower than the currently applicable permissible maximum speed, the current relevant information concerning the course of the road, particularly a determined recommended maximum speed, a determined deceleration strategy, a predefined minimum offer duration and/or a predefined maximal distance, the function unit FE initiates at a defined point in time the output of a prompt signal by a corresponding signal af to a display operating unit ABE. The display operating unit ABE comprises an information system HS and an operating system BE. Depending on the further development of the speed control system, according to a first alternative, the output can basically only be initiated when the determined new permissible maximum speed is lower than the desired speed maximally predefined by the driver. According to a second alternative, the output can take place independently of a desired maximum speed possibly predefined by the driver.

[0032] The operating element BE, by which the driver can acknowledge the prompt information, is further developed such that, at those times at which no prompt information is outputted, the driver can request a manual adaptation of the maximally desired speed +v. In addition, the operating element BE is further developed such that, in the case of an output of the prompt information, by way of a first actuating mode, the driver can acknowledge the requested permission of the automatic adaptation of the permissible maximum speed (signal z), or, by way of a second actuating mode, can reject the requested permission of the automatic adaptation of the permissible maximum temperature (signal a).

[0033] Only when the driver acknowledges the prompt signal during the output of the prompt information by actuating the operating element BE according to the first actuating mode, will the display operating unit ABE send back a corresponding permission signal z to the function unit FE. The function unit FE will then start the initiation of the automatic adaptation of the permissible maximum speed andcorresponding to the new maximum speed(if possible) an adaptation of the speed control while taking into account the new permissible maximum speed by causing a corresponding triggering of the driving unit AE and/or the braking unit BrE. For example, when the vehicle is in the so-called clear-travel mode, particularly in the case of a speed reduction, a controlling of the speed will take place for reaching the new maximum speed at the location of the relevant event. When the vehicle is in the so-called following mode with respect to a target object driving ahead, the following-travel control will (at first) be continued while taking into account the new permissible maximum speed. Simultaneously, when the manually triggered permission acknowledgment z is recognized, the retraction of the output of the prompt information will be initiated.

[0034] When, during of the output of the prompt information, the driver, by actuating the operating element BE according to the second actuating mode, rejects the permission of the automatic adaptation of the permissible maximum speed, the display operating unit sends a signal a back to the function unit FE. The function unit will then reject the newly determined permissible maximum speed and continue the current speed control. Simultaneously, when the manually triggered rejection is detected, the retraction of the output of the prompt information will be initiated.

[0035] In view of the invention, by means of available data e1, the function unit FE is now designed for first, determining the currently permitted permissible maximum speed, when the longitudinally guiding driver assistance system is activated. The function device FE simultaneously examines, as required, while taking into account the current vehicle speed v, whether events lying ahead are recognized which require a permissible maximum speed that competes with the current permissible maximum speed. In particular, a competing event will be recognized when at first an acceleration of the vehicle (for reaching the currently applicable permissible maximum speed) would be necessary and, within a defined time period, a subsequent deceleration of the vehicle for reaching the (reduced) permissible maximum speed would be required at the location of the event lying ahead. Such a detection may take place, for example, in that the function unit FE determines an acceleration strategy, which could be implemented in order to accelerate the vehicle at least in the direction of the currently applicable permissible maximum speed, and determines a deceleration strategy, which would have to be implemented in order to reach the new permissible maximum speed at the location of the event lying ahead. The time- and/or location-related spacing of the intersection point of the two strategies, thus, that point at which a display for permitting the new permissible maximum speed would have to be activated in order to, after the permission of the adaptation, request the change from the acceleration strategy to the deceleration strategy, will be taken into account such that, in the case of a distance between the current vehicle position and the intersection point that falls below a predefined limit distance, a first output of a prompt information for permitting the automatic first setting of the permissible maximum speed would be suppressed. When the distance between the current vehicle position and the first-determined intersection point is sufficiently large, thus larger that the predefined distance, the first output of the prompt information for permitting the adaptation or the first setting of the permissible maximum speed currently applicable because of the currently applying situation will be initiated immediately after the activation of the system and the availability of all relevant information or at a defined time- and/or location dependent point in time after the activation of the longitudinally guiding driver assistance system.

[0036] A corresponding approach for determining whether, after the activation of the longitudinally guiding driver assistance system, a first display for permitting an automatic first setting of a permissible maximum speed is to be initiated or suppressed, will be explained by use of the illustration in FIGS. 2A and 2B.

[0037] FIG. 2A illustrates a course of a road St, on which a vehicle EGO equipped with a longitudinally guiding system according to the invention is moving at an own speed vist of approximately 80 km/h in the direction of a speed limit sign vE lying ahead, which permits a permissible maximum speed vmax_vE of 50 km/h. Before the speed limit sign vE, a permissible maximum speed of vmax_aE of 100 km/h is allowed.

[0038] The driver of the vehicle EGO activates the longitudinally guiding driver assistance system at the current location tA, whereupon the currently applicable permissible maximum speed vmax_aE is determined. The location taE or the location-dependent point in time taE marks that point at which the first output of the prompt information for permitting the adaptation or the first setting of the permissible maximum speed vmax_aE currently applicable as a result of the currently prevailing situation could be initiated. This location taE is either determined by the fact that the first display would be initiated at a defined point in time after the activation tA of the longitudinally guiding driver assistance system or when all necessary information is available.

[0039] The location tAvE or the location-dependent point in time tAvE characterizes that point at which a prompt information for permitting an automatic adaptation of the permissible maximum speed to the new permissible maximum speed applicable from the location of the speed limit sign would have to be initiated in order to reach this new permissible maximum speed at the speed limit sign. This location tAvE is obtained by the intersection point S1 between the acceleration v_BaE1 (see bottom illustration of FIG. 2B), which can be implemented on the basis of the acceleration strategy, starting at the location of the conceivable first output taE, and the deceleration v_VvE, which can be implemented on the basis of the determined deceleration strategy, in order to be able to achieve the then applicable permissible maximum speed vmax_vE at the location of the event vE lying ahead.

[0040] In this example, the distance dT between the location taE of the conceivable first output and the location tAvE of the 2.sup.nd output of the prompt information is not analyzed as to whether an event lying ahead is present that competes with the first output (acceleration prompt). When the distance dT is shorter than a predefined limit distance dTG, the first output of the prompt information will be suppressed, but if the distance dT is longer than the predefined limit distance dTG, the first output will be initiated.

[0041] As an alternative to the suppression of the first output of the prompt information, it would also be contemplated to use, instead of the original acceleration strategy, a new acceleration strategy with a lower acceleration vBaE2 and therefore determine and correspondingly analyze the then resulting new intersection point S2 between the acceleration v_BaE2 implementable on the basis of this determined acceleration strategy, also beginning at the location of the possible first output taE, and the deceleration v_VvE implementable on the basis of the determined deceleration strategy. In this example, the distance dT between the location taE of the conceivable first output and the location tAvE2 of the 2.sup.nd output of the prompt information will be longer than the predefined limit distance dTG, so that the event lying ahead will not be classified as being competitive. Accordingly, the first output of the prompt information is initiated first, and the output of the second prompt information is initiated when the new location tAvE2 is reached. If the distance were still shorter than the predefined limit distance dTG, the first output would finally be suppressed.

[0042] A driver assistance system further developed in this manner could prevent driver irritation when activating the system.

[0043] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.