DE102012214206B4 - Method for detecting the curvature of a lane course during fully automatic vehicle guidance - Google Patents

Abstract

Method for detecting the curvature of a lane course during the operation of a fully automatic driver assistance system designed for driver-independent vehicle guidance by means of a control unit which, during operation of this driver assistance system, actuates a drive unit and/or brake unit when the current or future lane curvature is determined to be smaller than a predetermined maximum permitted lane curvature in such a way that the motor vehicle maintains a predetermined distance from a vehicle in front that has been detected as a target object, and which controls the actuators of a steering system in such a way that the motor vehicle is kept within its recognized lane, characterized in that the future lane curvature (a, b1, b2, b3) as a function of position-dependent data (B1, B2, B3) of the vehicle in front detected as a target object (ZO) and as a function of the driven trajectory (Tr) of the target object (ZO) is determined, the driven Trajectory (Tr) of the target object (ZO) by continuously determining and, if necessary, temporarily storing the position data (B1, B2, B3) of the target object (ZO) and/or the position data of the target object (ZO) relative to the motor vehicle (F) and at least partially Evaluation of the stored position data (B1, B2, B3) is determined.

Description

The invention relates to a method for detecting the curvature of a lane course during fully automatic, driver-independent vehicle guidance according to the preamble of claim 1.

Many vehicle manufacturers are already developing fully automatic driver assistance systems designed for driver-independent vehicle guidance, which are intended to relieve the driver of the driving task in certain traffic situations by taking over the driving task completely automatically. An example is what is known as a traffic jam assistant, which can be used in traffic jams on freeways. In this case, below a predetermined limit speed of z. B. 60 km / h, both the longitudinal guidance (similar to a distance-based or active cruise control), as well as the lateral guidance to keep the vehicle within the lane are carried out automatically. In a special embodiment of such traffic jam assistants, it should even be allowed for the driver to take his hands off the steering wheel at least for a certain period of time.

Such fully automatic driver assistance systems, designed for driver-independent vehicle guidance, require high safety requirements since, in the event of a fault, there could be high risks both for the driver and for other road users.

From the DE 10 2010 021 591 A1 a method for operating such a driver assistance system is already known, with a plausibility monitoring module continuously checking whether an error is present. Various situations are defined as an error, e.g. B. that the vehicle is driving too fast or backwards, that a certain minimum distance to a vehicle ahead is undershot and / or that the vehicle leaves the lane. If such a fault is detected, at least one driving intervention serving to bring the motor vehicle into a safe state is carried out.

Furthermore, driver assistance systems of this type may only support the driver within certain framework conditions, in part due to statutory provisions. Such a driver assistance system can only carry out the driving task up to a maximum permitted curvature. If the lane to be traveled has a greater curvature than the maximum permitted, automatic vehicle guidance (for safety reasons) cannot be continued. The problem here is if the curvature that is too great is only recognized very late, since the fully automatic vehicle guidance cannot be continued, which can then result in risks for the driver and/or the other road users.

From the DE 10 2009 050 399 A1 a method for controlling a driver assistance system with detection of a curvature in the course of the lane is already known. In addition, the DE 197 49 086 C1 a device for determining data indicative of the course of the lane. Further prior art disclose the DE 10 2011 002 911 A1 and the DE 10 2004 028 591 A1 .

The object of the invention is now to specify a method for operating a motor vehicle during the operation of a fully automatic driver assistance system designed for driver-independent vehicle guidance that is improved with regard to early detection of a future (too large) curvature of the lane.

This object is achieved by a method according to patent claim 1. Advantageous developments result from the dependent claims.

In principle, the invention is based on a method for operating a motor vehicle or a method for detecting the curvature of a lane course during the operation of a fully automatic driver assistance system designed for driver-independent vehicle guidance. Driver assistance systems of this type are designed in such a way that, when predetermined framework conditions are present - e.g. when driving on the motorway and at a speed that is below a predetermined limit speed - they use one or more control units to control the actuators of an (electrically operated) steering system and/or the actuators of a drive system and/or control the braking system in such a way that the vehicle is guided or kept within its own lane, taking into account a vehicle driving ahead or a vehicle in front that has been detected as a target object and possibly other road users. The longitudinal guidance can take place in a manner analogous to the longitudinal guidance of an adaptive cruise control (ACC). Another essential condition is the determined lane curvature. This determined current or future lane curvature must be less than a specified maximum permitted lane curvature in order to drive the motor vehicle independently of the driver.

The basic idea of the invention is now to specify a possibility or method by which the curvature of the lane can be determined at a very early stage. Accordingly sign The inventive method is characterized in that the future lane curvature is determined as a function of position-dependent data of the vehicle in front detected as a target object.

The position-dependent data can advantageously be a relative angle of the target object to the motor vehicle, i. H. the future curvature of the lane is determined as a function of the determined relative angle of the target object to the motor vehicle. This relative angle can be determined, for example, from the data from a camera system pointing forward and recognizing the target object.

Alternatively or additionally, the future curvature of the lane can also be determined by an (additional) evaluation of position data of the vehicle in front detected as a target object. The position or the position data of the target object can be determined by means of a corresponding sensor system that is installed in the vehicle, e.g. B. a camera system or transmitted by car-to-car communication to your own vehicle.

Advantageously, the future lane curvature can be determined at the same time as a function of the position data of the motor vehicle and the target object, ie by evaluating the position data of the target object relative to the corresponding motor vehicle. If the relative position of the target object is known, the distance and offset of the target object from the motor vehicle can be used to determine whether the future lane curvature will be greater than the specified maximum permitted lane curvature.

An even more accurate estimation of the future lane curvature can be made possible according to the invention by determining the future lane curvature directly as a function of the known trajectory driven by the target object. According to the invention, the trajectory traveled by the target object is determined by continuous determination and, if necessary, temporary storage of the position data and/or the position data of the target object relative to the motor vehicle and at least partial evaluation of the stored position data.

In order to secure the future lane curvature determined by evaluating position data of the target object, further data such as e.g. B. the data of a navigation system and / or data determined from recognized lane markings are evaluated.

If it is now determined by evaluating the position data of the target object and possibly other relevant data or information that the future lane curvature will be greater than the specified maximum permitted lane curvature, an optical, acoustic and/or haptic warning is advantageously issued to the driver of the motor vehicle, which informs the driver that fully automatic vehicle guidance can no longer be continued. Additionally or alternatively, a takeover request can also be issued to the driver of the motor vehicle.

Additionally or alternatively, if the future lane curvature is determined to be greater than the specified maximum permitted lane curvature, an automatic braking intervention to brake the motor vehicle can also be carried out in order to prevent the vehicle from having a relatively high speed when the maximum permitted lane curvature is reached or exceeded and due to this the vehicle would then continue to roll unchecked if the fully automatic vehicle guidance were aborted.

Advantageously, in such situations, such a braking intervention is carried out that the vehicle comes to a standstill within a specified time interval or within a specified distance if the driver does not take over the task of driving again during the braking process or actively intervene in the vehicle guidance. Ideally, such a braking intervention is carried out that the motor vehicle comes to a standstill within the distance that existed between the motor vehicle and the vehicle in front at the time when it was recognized that the future lane curvature will be greater than the maximum permitted lane curvature.

Various measures can be taken with regard to the lateral guidance of the vehicle after determining that the future lane curvature will be greater than the maximum permitted lane curvature. According to a first alternative, the steering actuators of the steering system can be controlled in such a way that the motor vehicle continues to be guided along a lateral guidance request or lateral guidance trajectory determined or requested by the fully automatic driver assistance system designed for driver-independent vehicle guidance, i.e. the vehicle continues to be guided within the lane or track center held. Alternatively, however, in an advantageous development of the invention, the steering actuators of the steering system can also be controlled in such a way that the motor vehicle is guided along a newly determined transverse control fall-back trajectory. In this case, for example, it might make sense to park the vehicle on the right or left bring any edge of your own lane to a halt.

The invention is explained in more detail using the following exemplary embodiment. The only figure shows the first traffic situation to illustrate the determination of the future lane curvature. This determination can take place within a control unit or distributed over a number of control units provided for this purpose.

The figure shows a motorway section with two lanes FS1 and FS2, with a first motor vehicle F and a preceding vehicle ZO in a traffic jam situation in the right-hand lane FS1. The motor vehicle F is equipped with a fully automatic driver assistance system, a so-called traffic jam assistant, designed for driver-independent vehicle guidance. Due to the active traffic jam assistant, the vehicle F is guided both longitudinally and laterally fully automatically, in such a way that the vehicle is guided within lane FS1 at a predetermined distance from the detected target object ZO.

During driver-independent vehicle guidance, the future curvature of the lane is now continuously determined by evaluating position data of the vehicle in front that has been detected as a target object (ZO). The figure shows two different options for this.

According to a first alternative, the future lane curvature a is determined by comparing the position data A of the motor vehicle F with the position data B3 of the target object ZO at the same time, i.e. by evaluating the relative position data of the target object ZO to the corresponding motor vehicle F, in such a way that (mentally) a direct Connection line VL is drawn between the motor vehicle F and the ZO and from this the future lane curvature a is determined. As the figure shows, this type of determination is somewhat imprecise, since this determined lane curvature would only be present if the motor vehicle F were to head for the current position B3 of the target object ZO by the shortest route.

In order to obtain a better or more precise estimate of the future curvature of the traveled lane, as part of an alternative procedure, the future lane curvature is determined directly from the traveled trajectory Tr of the target object, i. H. the lane curvature (b1, b2 and b3) present there is determined from these data at predetermined points B1, B2 and B3 or continuously at each position that the target object ZO has occupied. The fact that the motor vehicle F travels at least a similar trajectory as part of the fully automatic vehicle guidance as it drove the target object ZO, the future curvature of the lane curvature traveled by the motor vehicle can be determined relatively precisely and corresponding measures (brake intervention, takeover request) can be initiated at an early stage.

Claims (10)

Method for detecting the curvature of a lane course during the operation of a fully automatic driver assistance system designed for driver-independent vehicle guidance by means of a control unit which, during operation of this driver assistance system, actuates a drive unit and/or brake unit when the current or future lane curvature is determined to be smaller than a predetermined maximum permitted lane curvature in such a way that the motor vehicle maintains a predetermined distance from a vehicle in front that has been detected as a target object, and which controls the actuators of a steering system in such a way that the motor vehicle is kept within its own lane, characterized in that the future lane curvature (a, b1, b2, b3) as a function of position-dependent data (B1, B2, B3) of the vehicle in front detected as a target object (ZO) and as a function of the driven trajectory (Tr) of the target object (ZO) is determined, the driven e Trajectory (Tr) of the target object (ZO) by continuously determining and, if necessary, temporarily storing the position data (B1, B2, B3) of the target object (ZO) and/or the position data of the target object (ZO) relative to the motor vehicle (F) and at least partial evaluation of the stored position data (B1, B2, B3) is determined. procedure after claim 1 , characterized in that the future lane curvature (a, b1, b2, b3) is determined as a function of the relative angle of the target object (ZO) to the motor vehicle (F). Method according to one of the preceding claims, characterized in that the future lane curvature (a, b1, b2, b3) is determined by evaluating position data (B1, B2, B3) of the vehicle in front detected as the target object (ZO). Method according to one of the preceding claims, characterized in that the future lane curvature (a) is determined as a function of the position data (A) of the motor vehicle and the position data (B3) of the target object (ZO) at the same time. Method according to one of the preceding claims, characterized in that further data, in particular data from a navigation system and/or data from recognized lane markings, are evaluated to determine the future lane curvature (a, b1, b2, b3). Method according to one of the preceding claims, characterized in that if the future lane curvature (a, b1, b2, b3) is determined to be greater than the specified maximum permitted lane curvature, a warning is sent to the driver of the motor vehicle and/or a request to the driver of the motor vehicle to take over is issued. Method according to one of the preceding claims, characterized in that if the future lane curvature (a, b1, b2, b3) determined is greater than the specified maximum permitted lane curvature, automatic braking intervention is carried out to brake the motor vehicle. procedure after claim 7 , characterized in that such a braking intervention is carried out that the motor vehicle (F) comes to a standstill within a predetermined time interval or within a predetermined distance. procedure after claim 7 or 8th , characterized in that such a braking intervention is carried out that the motor vehicle (F) comes to a standstill within the distance that existed between the motor vehicle (F) and the vehicle in front (ZO) at the time when it was recognized that the future lane curvature will be greater than the maximum permitted lane curvature. Method according to one of the preceding claims, characterized in that if the future lane curvature (a, b1, b2, b3) is determined to be greater than the specified maximum permitted lane curvature, the steering actuator system of the steering system is controlled in such a way that the motor vehicle (F) moves along a Based on the fully automatic driver assistance system designed for driver-independent vehicle guidance determined or requested lateral guidance request or lateral guidance trajectory or is guided along a newly determined lateral guidance fallback trajectory.

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