Method for the Cruise and/or Range Control of Motor Vehicles

A method for cruise and/or range control of motor vehicles with range-controlled cruise control systems, wherein, during a determination of a desired acceleration value, for reaching a predefined speed and/or a predefined distance to a target object traveling ahead during a following travel, specific data of a target object traveling ahead and of a front object traveling in front of the target object are taken into account. As a function of the specific data of the target object driving ahead, a first desired pre-acceleration value is determined and, as a function of the specific data of the front object driving ahead, a second desired pre-acceleration value is determined. From the first desired pre-acceleration value and the second desired pre-acceleration value, by weighting the two desired pre-acceleration values, the relevant desired acceleration value is determined.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1illustrates a traffic situation at an intersection with a traffic light circuit. Three vehicles F0, F1 and F2 are situated at a junction of the intersection. Here, vehicle F0 is equipped with a range-controlled cruise control system and is currently in a following-travel mode with respect to the target object F1 driving ahead, in which case, here, additionally relevant data of the front object F2 situated in front of the target object F1 are taken into account. In this example, there is a first distance d1 between the (control) vehicle F0 and the target object F1, and a second distance d2 between the (control) vehicle F0 and the front object F2.

As soon as the traffic light changes to a green light, the front object F2 would start driving first here, while the target object F1 would probably still be stopped. When this starting of the vehicle F2 is detected and is evaluated within the scope of the speed control, vehicle F0 can, for example, already start driving isochronously with the target object F1.

FIG. 2illustrates a flow chart for determining a desired acceleration value for reaching a predefined speed or a predefined distance ds1 with respect to a target object F1 driving ahead. The desired speed and the distance ds1 can be either predefined by the driver or can be determined by use of various parameters by the range-controlled cruise control system itself. When a detected target object—here, F1—is situated in front of the motor vehicle—here F0—equipped with the range-controlled cruise control system, which motor vehicle F0 is moving at a speed lower than the predefined desired speed, a control of the speed takes place while taking into account the slower-driving target object F1.

In this case, the approach according to the invention is as follows. First, a first desired pre-acceleration value a1 is determined on the basis of the specific data of the target object F1, particularly the current distance d1 between the vehicle F0 and the target object F1 and, for example, the speed v0 of the own vehicle F0 and that of the target object F1 (=v1) while taking into account the predefined desired distance ds1 between the vehicle F0 and the target object F1. Here, the further environment can already also be taken into account. Further, a second desired pre-acceleration value a2 is determined on the basis of the specific data of the front object F2 situated in front of the target object F1, particularly the current distance d2 between the vehicle F0 and the front object F2 and, for example, the speed v0 of the own vehicle F0 and of the front object F2(=v2) while taking into account a defined desired distance ds2 (increased with respect to the desired distance ds1) between the vehicle F0 and the front object F2. Here, the determination can be done with the same environmental conditions or with the same parameterization as during the determination of the first desired pre-acceleration value a1. In this case, the desired distance d2 is, for example, defined such that it is a result of the desired distance ds1 between the vehicle F0 and the target object F1 and a defined distance between the target object F1 and the front object F2 (taking into account a defined length of the target object F1). As an alternative, the computing can also take place by use of a desired distance ds2 that is independent of the first desired distance ds1.

From these two determined desired pre-acceleration values a1 and a2, which may assume positive as well as negative values, in the following, by a situational weighting of the two desired pre-acceleration values a1 and a2, the desired acceleration value a is determined which is finally relevant to the speed control. In this case, the determination can contain the following formula component:

wherein the parameters K1 and K2 are used as weighting factors for the situational weighting of the two desired pre-acceleration values. The two weighting factors K1 and K2 may assume values between 0 and 1, in which case, however, the sum of the two factors K1 and K2 should always result in 1. For determining the weighting factors K1 and K2, among others, different parameters or data u are used and analyzed. The data u may, for example, be present information concerning the course of the road, the road type, the number of lanes, traffic lights, etc. and/or information of other traffic participants. Likewise, during the weighting, the preceding sign and/or the amount of the desired pre-acceleration value or also their difference can be taken into account. It is essential that, from the two determined desired pre-acceleration values a1 and a2, by way of a situational weighting, the relevant desired acceleration a is determined, and not always only the determined first or the determined second desired pre-acceleration value a1 or a2 is implemented one-to-one.

This method according to the invention for the determination of a desired acceleration value and/or a desired deceleration value, while simultaneously taking into account specific data of the target object and of the front object driving in front of the target object permits a behavior that is similar to that of a driver and is plausible during the range-controlled cruise control in all traffic situations. In particular, as a result, a reaction can take place earlier at low expenditures to a situation change because only an interpretation of the environment is carried out and subsequently with respect to both objects, an instance of the same control device is computed with the same prioritization.