DE102011012784A1 - Method for collision prevention or collision sequence reduction of motor car, involves using intersection card of computed parameter map for determining transverse displacement of vehicle to assigned guidance assignment dot - Google Patents

Abstract

The method involves acquiring an object (12) in the surrounding environment of motor vehicle (11). A parameter map (22) depicting the transverse displacement (21) of motor vehicle for assigned guidance assignment dot, is computed for each detected object. An intersection card (31) of computed parameter map is used for determining the transverse displacement of motor vehicle to an assigned guidance assignment dot, to prevent the collision of vehicle with each detected object. An independent claim is included for assistance system for collision prevention or collision sequence reduction of motor car.

Description

The invention relates to a method for collision avoidance or collision consequences reduction according to claim 1. Furthermore, the present invention relates to an assistance system for a motor vehicle for collision avoidance or Kollisionsfolgenmeinderung according to claim 10.

In order to avoid collisions of motor vehicles or to reduce the collision strength, methods and devices are known which monitor the environment of the motor vehicle by means of sensors and issue a warning to the driver when detecting an imminent collision and / or perform an automatic steering or braking operation. In particular, preceding or stationary objects are detected on the lane of the motor vehicle. For these objects the time reserves Time-To-Brake and Time-To-Steer are calculated. These indicate the remaining time until the beginning of the last possible braking or steering maneuver, by which the driver can barely prevent a collision. The so-called Time-To-React is the maximum of Time-To-Brake and Time-To-Steer, ie the remaining time until the driver's last possible collision avoidance maneuver. Depending on the time-to-react, a warning, partial braking or full braking is initiated. For the calculation of the time-to-steer - and thus the last possible evasive maneuver - it is assumed that the last possible steering maneuver by a cornering with a constant radius and maximum lateral acceleration ( Jörg Hillenbrand et al., A Multilevel Collision Mitigation Approach - Its Situation Assessment, Decision Making, and Performance Tradeoffs, IEEE Transactions on Intelligent Transportation Systems, 2006 ) can be modeled.

From the DE 10 2004 056 027 a method and vehicle assistance system for preventing collisions or reducing a collision strength of a vehicle is known in which the driving speed and direction of movement of one's own vehicle as well as objects (other vehicles, guardrails) in the vehicle environment and their position, speed and direction of movement relative to the own vehicle are detected, and in which a system response is triggered when a situation assessment taking into account the current and predicted future location of the objects indicates that there is a risk of a collision. The system reaction can be different escalation levels, z. B. include a warning followed by partial braking followed by full braking. The calculation of meaningful times for the system reaction takes place taking into account the action options "braking" and "avoidance", which focus on a collision avoidance.

The prior art has several disadvantages. In part, in practice, non-feasible evasive maneuvers are calculated or only individual objects are considered, which means that it is not taken into account whether there is an alternative possibility when considering all detected objects. Finally, the state of the art does not take into account the demands on the human driver when carrying out a collision maneuver

The object of the invention is to provide a new, efficient calculation method for the last possible evasive maneuver, which instead of a not feasible in reality evasive maneuver model such. As a circular path, a polynomial of a physically movable evasive maneuver used. In addition, the method is to calculate whether, considering all objects, there is actually a possibility for the driver to evade, and to consider the requirements of a human driver when carrying out a collision maneuver.

This object is achieved by the method according to claim 1, as well as an assistance system for a motor vehicle according to the independent claim 10. Advantageous embodiments of the invention are the subject of the dependent claims.

According to the invention, it is provided that first an object in the environment of the motor vehicle is detected. The environment of the motor vehicle preferably comprises the space area in front of and behind the motor vehicle and the two-sided side space areas. Further preferably, position, orientation, speed and acceleration are detected by each object.

The aim now is to determine and evaluate all possible mobile and collision-free avoidance trajectories of the system vehicle. For this purpose, a parameter map is calculated for each detected object, which shows which transverse offset of the motor vehicle is necessary for an associated steering application time in order to avoid a collision with the detected object. Preferably, each point of the parameter map corresponds to a specific parameter vector p and indicates whether the associated evasive maneuver leads to a collision or not. The parameter map thus shows which areas of the discretized parameter space of p are collision-free. The parameter map must be recalculated for each scenario. It goes without saying that for storing the parameter map any suitable data structure such. B. an array can be used.

Subsequently, an intersection map of the calculated parameter maps of all captured Objects, for determining at least one transverse offset of the motor vehicle to an associated steering application time, with the collisions with each detected object are avoided, calculated. This is based on the consideration that the parameter map should always be recalculated for each scenario. For reasons of computing time, however, it is at least extremely difficult to check each point individually when creating the parameter map. Therefore, the following assumptions are advantageously used:
Consider two scenarios S1 and S2 with identical driving state of the system vehicle but each different obstacles H1 and H2. For these scenarios, two parameter maps M1 (p) and M2 (p) result, which indicate whether the evasive maneuver associated with the parameter vector p leads to a collision (M1 (p) = 1 or M2 (p) = 1) or not (M1 (p) = 0 or M2 (p) = 0). If the scenarios S1 and S2 are now combined to form a new scenario that contains both the obstacle H1 and the obstacle H2, the following applies to the resulting intersection map at point p: M (p) = max (M2 (p), M2 (p)).

The parameter cards can therefore be combined by means of a simple MAX link to form an interface set.

In another preferred embodiment, calculating the parameter map for each detected object comprises calculating a boundary line, wherein the boundary line on the parameter map separates a collision-free area and a collision area. If, in one scenario, there is only one obstacle with a simple, geometrically connected structure, there is also a coherent collision area on the parameter map. This area can be described by one or two boundary lines, which vividly correspond to the two events "motor vehicle with minimum distance left to object passing" and "motor vehicle with minimum distance right past object". Consequently, by examining the movement of the corners of the motor vehicle and the detected objects, the parameters of an evasive maneuver to the left or right, which lead to a contact of the motor vehicle and Objekttrajektorien be determined. The boundary lines thus correspond to the parameters for which, in the considered scenario, the corners of the motor vehicle collide with the corners of the detected object. By calculating the boundary lines, it is possible to dispense with the individual checking of each individual point for the recalculation of the parameter map.

Furthermore, the parameter map can preferably be calculated on the basis of the calculated boundary lines with the aid of a filling algorithm (eg flood fill). Starting from a point within the parameter map, its neighboring points are tested for whether they also contain the old color. Each found point with the old color is immediately replaced by the new color.

It is advantageous to calculate a boundary line with the aid of a lookup table. Of course, any other data structure is conceivable that contains corresponding precalculated data. It is crucial to perform a considerably faster value search within a data field instead of the respective review of the individual points.

In a further advantageous embodiment, the last possible evasive maneuver is determined by first detecting all contiguous collision-free areas on the interface, which have at least one specified minimum extent. The extent is defined by the dimensions transverse offset and steering time. For the detection of the contiguous areas exist a variety of efficient algorithms, such. B. again Floodfill.

In addition, it is advantageously considered which requirements a collision avoidance maneuver places on the ability of the driver. Preferably, this is done by evaluating the size of the collision-free area on the parameter map. For small collision-free areas around the trajectory to be evaluated, the driver has only a correspondingly small number of collision-free avoidance trajectories available. For collision avoidance, the driver therefore has to comply very precisely with the parameters of the evasive maneuver. For large areas, the demands on the driver are correspondingly lower. Preferably, therefore, all alternate parameter sets which lie within the detected collision-free regions and have a fixed minimum distance to the collision regions are determined, wherein the alternate parameter sets are defined by a transverse offset of the motor vehicle (Δy _soll ) and an associated steering angle instant (t _start ). Subsequently, the alternate parameter set is determined with the latest assigned steering application time. This represents the last possible evasive maneuver.

Preferably, when detecting an object, its position and parameters derivable from the position are detected. These derivable parameters include, among other things, the alignment, speed and acceleration of the detected objects. However, further parameters derivable from the position can also be used. It is obvious that the parameters do not necessarily have to be calculated from the position, but also measured directly can be. It is conceivable, for example, that the motor vehicle communicates with the objects in its surroundings and the required parameters are transmitted in this way. The calculation from other known parameters as the position is conceivable.

In a further advantageous embodiment, the object is detected in the environment of the motor vehicle by means of radar, lidar, video and / or ultrasonic sensors. Of course, any other type of suitable sensors such. B. a wheel speed sensor conceivable. Optionally, a combination of the sensors can also be advantageously used.

Preferably, status data of the motor vehicle and / or the objects, in particular the position of the motor vehicle and / or the objects by means of a map-based satellite-based navigation system (eg Global Positioning System, Galileo), radar, lidar, video and / or or ultrasonic sensors detected. In particular, the satellite-based navigation system can advantageously provide information on passive objects, on the road guidance or on the number of lanes on the basis of an electronic road map.

• • dem gewünschten Querversatz Δy_soll
• • dem gewünschten Startzeitpunkt des Ausweichmanövers t_start
• • der maximal zulässigen Querbeschleunigung a_ymax

Further preferably, avoidance trajectories are used to calculate the parameter map, the avoidance trajectories representing in particular substantially S-shaped curves. Advantageously, an evasion trajectory is modeled as a polynomial, wherein the coefficients of the evasive polynomial depend on the following parameters in addition to the current state data of the motor vehicle (eg speed, steering angle):

• • the desired transverse offset Δy _soll
• • the desired start time of the evasive maneuver t _start
• • the maximum permissible lateral acceleration a _ymax

For the calculation of the last possible avoidance maneuver, it is advantageously assumed that the maximum permissible lateral acceleration a _{ymax is} constant. The transverse offset Δy _soll and the start time of the evasive maneuver t _start , however, are always dependent on the respective scenario (vehicle speed, position / orientation / speed of the obstacles, etc.). The transverse offset Δy _soll and the last possible starting time t _start are mutually dependent. If more escape space is available, ie if a large transverse offset is possible, then the evasive maneuver can be started later than with a lower setpoint offset.

Any evasion trajectory of the motor vehicle. can therefore be described unambiguously by a parameter vector p = (t _start , Δy _soll ) with two degrees of freedom. The maximum permissible lateral acceleration and the current driving speed are assumed to be constant in a considered scenario and therefore do not have to be considered. In the search for evasive maneuvers, it must be calculated for each possible trajectory of the system vehicle whether or not it leads to a collision with another object, ie p → c, c = {no collision = 0; Collision = 1}.

Finally, the invention relates to an assistance system for a motor vehicle for collision avoidance or Kollisionsfolgenminderung, with an object detection means for detecting at least one object in the environment of the motor vehicle, a parameter map calculating means for calculating a parameter map for each detected object, such as the respective parameter map, which lateral offset of the motor vehicle is necessary at an associated steering application time to avoid a collision with the detected object, and an intersection map calculating means for calculating an intersection map of the calculated parameter maps of all detected objects, wherein the intersection map calculation means is adapted to at least by means of the intersection map to determine a transverse offset of the motor vehicle and an associated steering application time, are avoided with the collisions with each of the objects.

In the following the invention will be explained in more detail with reference to drawings. Showing:

1 the schematic representation of a motor vehicle and one or a plurality of objects in the vicinity of the motor vehicle,

2 the schematic representation of a scenario as well as the corresponding parameter map,

3 the schematic representation of two parameter maps and the calculated intersection map,

4 the schematic representation of a parameter map with calculated boundary line and

5 the schematic representation of an intersection chart with the last possible evasive maneuver

In all figures, only avoidance maneuvers are shown to the left for simplicity. Evasive maneuvers to the right are to be treated analogously.

1 shows the schematic representation of a motor vehicle 11 and one or a plurality of objects 11 in the vicinity of the motor vehicle 12 , In addition, the beginning of the braking process 13 each represented by a block arrow. On the left side is the scenario shown on the lane of the motor vehicle 11 an object 12 in this case another motor vehicle is located. In order to avoid a collision, the braking process must 13 be initiated at a certain point. Alternatively, a change of lane would be possible here.

On the right side the scenario is shown that not only in front, but also next to the motor vehicle 11 objects 12 namely, other motor vehicles are located. Dodge to the left is therefore not possible. To avoid a collision, the braking process must be done 13 be initiated at a certain point.

2 shows the schematic representation of a scenario as well as the corresponding parameter map 22 with a collision-free area 24 and two collision areas 23 , The x-axis 25 the parameter card 22 carries off the start time of the evasive maneuver t _start . The y-axis 26 carries the transverse offset Δy 21 from. An illustrated parameter pair 27 is within the collision free area 24 and represents an evasion trajectory, which does not lead to a collision of the motor vehicle with an object 28 , Another illustrated parameter pair 29 is located within the collision area 23 and represents an evasion trajectory, which leads to a collision of the motor vehicle with an object 30 ,

3 shows the schematic representation of two parameter cards 22 and the calculated intersection map 31 , Two scenarios and the corresponding parameter maps are shown on the left side, with an object in the upper scenario 12 on the lane to the left of the motor vehicle 11 is detected. The lower scenario becomes an object 12 on the lane of the motor vehicle 11 detected. On the right side is the intersection map 31 , so the combination of the two parameter cards shown, which is to be realized by a simple MAX link.

4 shows the schematic representation of a parameter map with calculated boundary line 41 indicating the collision-free area 24 from the collision area 23 separates. This clearly corresponds to the scenario "The motor vehicle drives with minimum distance left past the object". This can be done by examining the movement of the corners of the motor vehicle 11 and the detected object, the parameters of an evasive maneuver, which lead to a touch of the motor vehicle and Objekttrajektorien determined. The boundary line thus corresponds to the parameters for which in the illustrated scenario the corner of the motor vehicle 11 with the corners of the detected object 12 collided.

5 shows the schematic representation of an intersection map 31 the parameter pair 51 which represents the last possible evasive maneuver. It can be seen that around the parameter pair 52 , which is too close to the collision area 23 only a small non-collision area exists. Consequently, the driver of the motor vehicle stands 11 Only a very small number of collision-free evasion trajectories are available. For collision avoidance, the driver would have to comply extremely precisely with the parameters of the avoidance maneuver (setpoint offset, start time), which would overtax the driver. The alternate parameter set 51 represents the parameter pair with the latest assigned steering time and thus the last possible evasive maneuver.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004056027 [0003]

Cited non-patent literature

• Jörg Hillenbrand et al., A Multilevel Collision Mitigation Approach - Its Situation Assessment, Decision Making, and Performance Tradeoffs, IEEE Transactions on Intelligent Transportation Systems, 2006 [0002]

Claims (10)

Method for collision avoidance or collision consequence reduction with the steps: - Detecting at least one object ( 12 ) in the environment of a motor vehicle ( 11 ), - calculating a parameter map ( 22 ) for each detected object ( 12 ), which shows which transverse offset ( 21 ) of the motor vehicle ( 11 ) at an associated steering time is necessary to collide with the detected object ( 12 ), and - calculating an intersection map ( 31 ) of the calculated parameter cards ( 22 ) of all detected objects ( 12 ), for determining at least one transverse offset ( 21 ) of the motor vehicle ( 11 ) at an associated steering time, with which collisions with each detected object ( 12 ) be avoided. Method according to claim 1, characterized in that the calculation of the parameter map ( 22 ) for each detected object ( 12 ) calculating a boundary line ( 41 ), wherein the boundary line ( 41 ) on the parameter card ( 22 ) a collision-free area ( 24 ) and a collision area ( 23 ) separates. Method according to claim 2, characterized in that the calculation of a boundary line ( 41 ) using a lookup table. Method according to one of claims 1 to 3, characterized in that a determination of the last possible evasive maneuver with the aid of the intersection quantity map ( 31 ) he follows. Method according to one of claims 1 to 4, characterized in that the determination of the last possible evasive maneuver comprises the steps - detecting all contiguous collision-free areas ( 24 ) on the interface ( 31 ) having at least one predetermined minimum extent - determining all alternate parameter sets ( 27 . 29 . 51 . 52 ) within the detected collision-free areas ( 24 ) and a fixed minimum distance to the collision areas ( 23 ), wherein the alternate parameter sets ( 27 . 29 . 51 . 52 ) by a transverse offset ( 21 ) of the motor vehicle ( 11 ) (Δy _soll ) and an associated steering angle instant (t _start ) are defined. Determining the alternate parameter set with the latest assigned steering-in time ( 51 ). Method according to one of claims 1 to 5, characterized in that during the detection of an object ( 12 ) whose position and derived from the position parameters are detected. Method according to one of claims 1 to 6, characterized in that the object ( 12 ) in the environment of the motor vehicle ( 11 ) is detected by means of radar, lidar, video and / or ultrasonic sensors. Method according to one of claims 1 to 7, characterized in that status data of the motor vehicle ( 11 ) and / or objects ( 12 ), in particular the position of the motor vehicle ( 11 ) and / or objects ( 12 ) are detected by means of a map-based satellite-based GPS system (Global Positioning System), radar, lidar, video and / or ultrasonic sensors. Method according to one of claims 1 to 8, characterized in that for calculating the parameter map ( 22 ) Avoidance trajectories ( 28 . 30 ), the avoidance trajectories ( 28 . 30 ) represent in particular substantially S-shaped curves, which by a transverse offset ( 21 ) of the motor vehicle ( 11 ) (Δy _soll ) and an associated steering angle instant (t _start ) are defined. Assistance system for a motor vehicle for collision avoidance or collision sequence reduction, in particular for carrying out the method according to one of claims 1 to 9, comprising: object detection means for detecting at least one object ( 12 ) in the environment of the motor vehicle ( 11 ), - a parameter map calculating means for calculating a parameter map ( 22 ) for each detected object ( 12 ), such that the respective parameter map ( 22 ) shows which transverse offset ( 21 ) of the motor vehicle ( 11 ) at an associated steering-in time is necessary in order to collide with the detected object ( 12 ), and - an intersection map calculation means for calculating an intersection map ( 31 ) of the calculated parameter cards ( 22 ) of all detected objects ( 12 ), wherein the intersection map calculating means is adapted to be executed by means of the intersection map ( 31 ) at least one transverse offset ( 21 ) of the motor vehicle ( 11 ) and an associated steering application time, with which collisions with each of the objects ( 12 ) be avoided.

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