Method and device for carrying out collision-avoiding measures

Abstract

The invention relates to a method for carrying out one or more collision-avoiding measures of a vehicle, in particular a motor vehicle. In the method, the positions of static and dynamic objects 11 are detected in a step 10, and one or more trajectories 21 which avoid collisions with the detected objects 11 are determined for the vehicle in a step 20. According to the invention, a danger value 23 for the determined trajectory 21 or for each of the determined trajectories 21, is determined continuously or periodically in a further step 22. This danger value 23 constitutes a measure for the forces which act on the vehicle when the respective trajectory 21 is passed through. The collision-avoiding measures are then carried out in a step 27 if the determined danger value 23, or the determined danger values 23, is/are above a selected or predefined threshold value 26. In addition, the invention relates to a device for carrying out the method.

Claims

1. A method for carrying out one or more collision-avoiding measures in a motor vehicle, comprising: detecting positions of static and dynamic objects; determining at least one trajectory which avoid collisions of the vehicle with the detected objects; determining a danger value for each of the determined at least one trajectory, wherein in order to determine the danger value on the basis of the current speed and acceleration of the vehicle, a maximum lateral acceleration of the vehicle is determined when the at least one trajectory is passed through, the lateral acceleration being evaluated using a probability value, wherein the probability value constitutes a measure of whether the driver would carry out a manoeuver with a lateral acceleration which is comparable with the determined lateral acceleration, wherein the evaluated lateral acceleration then corresponds to the at least one danger value, wherein the danger value is determined continuously or periodically and is a measure of one or more forces which would act on the vehicle when the at least one trajectory is passed through; and carrying out the collision-avoiding measures in the event of at least one of the determined at least one danger values being above a selected or predefined threshold value.

2. The method according to claim 1, wherein a period of time up to which a collision with the closest object located in the travel path of the vehicle is avoided by braking the vehicle is determined, and a first collision-avoiding measure is carried out when the period of time undershoots a time threshold value or a plurality of collision-avoiding measures are respectively carried out when one of a plurality of time threshold values are undershot before the at least one danger value is above the threshold value.

3. The method according to claim 1, wherein in order to determine the at least one trajectory for the vehicle, the positions of dynamic objects are predicted continuously or periodically, and the at least one trajectory are adapted to the predicted positions continuously or periodically.

4. The method according to claim 1, wherein in the event of a plurality of trajectories being determined, the danger value of that trajectory with the lowest determined maximum lateral acceleration is selected and the collision-avoiding measures are carried out if the selected danger value is above the selected or predefined threshold value.

5. The method according to claim 1, wherein one of the collision-avoiding measures comprises the braking of the vehicle.

6. The method according to claim 5, wherein the braking takes place by means of intervals with the same or different braking forces or by means of a continuously applied braking force with constant increasing or decreasing braking force.

7. The method according to claim 1, wherein one of the collision-avoiding measures comprises signalling a signal in the passenger compartment of the vehicle.

8. The method according to claim 7, wherein the signalling of the signal comprises displaying a visual signal, playing back a sound or a sound sequence and/or the haptic signalling for the driver of the vehicle.

9. The method according to claim 1, wherein the execution of a collision-avoiding measure is interrupted by the intervention of the driver in the control, in particular by means of manual braking.

10. The method according to claim 1, wherein the threshold value is defined by making a selection from a plurality of predefined threshold values, before the method is carried out.

11. A device for carrying out one or more collision-avoiding measure in a motor vehicle, the device comprising: a laser scanner configured to detect positions of static and dynamic objects; an electronic accessory device for assisting a driver of the motor vehicle, the electronic accessory device configured to: determine at least one trajectory which avoid collisions of the vehicle with the detected objects, determine a danger value for each of the determined at least one trajectory, wherein in order to determine the danger value on the bases of the current speed and acceleration of the vehicle, a maximum lateral acceleration of the vehicle is determined when the at least one trajectory is passed through, the lateral acceleration being evaluated using a probability value, wherein the probability value constitutes a measure of whether the driver would carry out a manoeuver with a lateral acceleration which is comparable with the determined lateral acceleration, wherein the evaluated lateral acceleration then corresponds to the at least one danger value, wherein the danger value is determined continuously or periodically and is a measure of one or more forces which would act on the vehicle when the at least one trajectory is passed through, and carry out the collision-avoiding measures in the event of at least one of the determined at least one danger values being above a selected or predefined threshold value, comprising activating at least one selected from a group consisting of a visual warning, an acoustic warning and a braking of the vehicle.

Description

(1) Further embodiments of the invention result from the dependent claims and from the exemplary embodiments which are explained in more detail with reference to the drawing. In the drawing:

(2) FIG. 1 shows the sequence of an exemplary embodiment of the method according to the invention,

(3) FIG. 2 shows the execution of successive first and further collision-avoiding measures, and

(4) FIGS. 3a-c show the determination of collision-avoiding trajectories.

(5) FIG. 1 shows the sequence of an exemplary embodiment of the method according to the invention. According to the method, in a step 10 positions of objects 11 are firstly detected. The detection is carried out, for example, by laser scanning with a laser scanner which is mounted on a vehicle. These objects 11 can be static objects, for example parked vehicles and/or path boundaries and dynamic objects, for example vehicles travelling ahead or oncoming vehicles. In the case of detection, all the objects 11 in the surroundings of the vehicle are detected, in order to process their positions simultaneously.

(6) For the dynamic objects 11, future positions 13 are then predicted in a step 12 by means of additionally detected movements of the dynamic objects 11. An unexpected movement of the object 11 is therefore predetermined.

(7) In addition, the movement, in particular the speed and the acceleration, of the vehicle, that is to say the driver's vehicle, with which the method is carried out, is detected in a step 14. By taking into account the current speed and the current acceleration, a travel path 17 which the vehicle will supposedly travel along is then predicted in step 16. With the predicted travel path 17 of the vehicle, and with the positions and future positions 13 of the detected objects 11, objects 19a which are supposedly located in the region of the travel path of the vehicle are identified in a step 18. In addition, the object 19b which is assumed to be located next in the travel path of the vehicle, that is to say constitutes the closest obstacle to the vehicle, is determined in this step 18.

(8) In step 20, all the possible trajectories 21 which lead the vehicle past the detected objects 19b without a collision are then determined on the basis of the current and future positions 13 of the detected objects 19b. The positions 13 of the objects 19b and therefore also the possible trajectories 21 are preferably updated continuously or periodically.

(9) The determined trajectories 21 are then evaluated in a step 22, and a danger value 23 is determined for each of the trajectories 21 here. The danger value 23 of a trajectory 21 constitutes a measure of one or more forces which would act on the vehicle when the respective trajectory 21 is passed through. According to one exemplary embodiment, the maximum lateral acceleration which would act on the vehicle when the respective trajectory 21 is passed through is determined on the basis of the current speed and acceleration of the vehicle. This maximum lateral acceleration is then evaluated with a probability value 24 which constitutes a measure of whether the driver would carry out an avoidance manoeuvre with a lateral acceleration which is comparable to the determined lateral acceleration. The result of this evaluation, that is to say the evaluated lateral acceleration, is then assigned to the respective trajectory 21 as a danger value 23. The danger values 23 are also continuously or periodically updated in accordance with the abovementioned continuous or periodic updating of the trajectories 21.

(10) In the subsequent step 25, the determined danger values 23 are compared with a threshold value 26. If all the danger values 23 exceed the threshold value during the updating of the danger values, in step 27 a collision-avoiding measure, in particular braking of the vehicle, is carried out. A collision-avoiding measure is therefore carried out if every determined trajectory 21 which leads past the obstacle or obstacles (objects 19a) would apply lateral acceleration to the vehicle which there is a high probability 24 of the driver not selecting. This means that if a collision-avoiding measure is carried out, this measure takes place so promptly that although it would be possible to pass through trajectories 21 which would lead past the objects 19a without a collision, this measure takes place so late that intervention by the driver is improbable, and the driver therefore has not recognized the dangerous situation.

(11) According to this exemplary embodiment, the period of time up to which execution of braking, in particular when the travel path 17 continues to be followed, is still possible in order to avoid a collision with the closest object 19b, is determined in the step 28, additionally on the basis of the speed and movement determined in step 14 and on the basis of the position of the object closest in the travel path of the vehicle, determined in step 18. This period of time is compared with one or more time threshold values 29, and a first collision-avoiding measure, in particular visual or acoustic signalling in the passenger compartment of the vehicle, is carried out when one of the time threshold values 29 is undershot or whenever it is undershot.

(12) The execution of subsequent first and further collision-avoiding measures, such as occurs in step 27, is illustrated according to an exemplary embodiment in FIG. 2.

(13) FIG. 2 shows a travel situation of the vehicle in the regions 30 to 38. In the regions 32 to 38 different successive collision-avoiding measures 39 are carried out. These are plotted on a time axis 40. The negative acceleration, that is to say the braking force which, during braking, acts on the vehicle as a result of braking, is represented on the axis 42. The line 44 corresponds to the zero line during which the vehicle is therefore not braked. The line 46 corresponds to braking with a first low force, and the line 48 corresponds to braking with a second comparatively high force. The intervention by collision-avoiding measures 39 in the event of danger is represented by the (bold) curve 50.

(14) In the first region 30, the vehicle is travelling normally. In the second region 32, the determined period of time up to which braking has to be carried out in order to avoid a collision with the closest object 19b in the travel path undershoots a first time threshold value 29. In this region 32, a first collision-avoiding measure 39 is carried out. For example, it is displayed visually to the driver that braking should take place soon. In the region 34, the determined period of time undershoots a further time threshold value 29, since the vehicle is, for example, again approaching an object 19b. Here a further collision-avoiding measure 39 is carried out. The driver is warned, for example acoustically by means of a sound or a sound sequence, that the risk of the collision has increased and immediate braking should take place.

(15) If the driver does not react by manually braking, the danger values 23 of the possible trajectories 21 rise, since an avoidance manoeuvre would still be possible only with relatively high lateral accelerations. In the regions 36 and 38, the danger values 23 of the trajectories 21 then exceed the threshold value 26, and a further collision-avoiding measure 39 is carried out. The vehicle is braked. In the region 36, the vehicle is firstly braked slightly, for example for a second, in order to give the driver the possibility of avoiding a collision manually. If the driver still does not react, in region 38 the vehicle is braked severely until it comes to a standstill, for example.

(16) According to one exemplary embodiment, the time threshold values 29 and the severity and duration of the braking can be configured.

(17) FIGS. 3a to 3c show the detailed determination of the trajectories 21 which lead past determined objects 19a, according to an exemplary embodiment of the invention.

(18) FIG. 3a shows the vehicle 52 which corresponds to the driver's vehicle, and a detected object 54 which corresponds, for example, to a further vehicle and is located in the travel path of the vehicle 52. On the basis of a coordinate system with the axes x and y, the vehicle 52 moves at a speed 56 in the direction x. The object 54 also moves and therefore corresponds to a dynamic object. Here, the object 54 moves in another direction to the vehicle 52, wherein the object 54 also moves in the direction x at a speed 58 when the directional components are decomposed.

(19) The times are determined which the vehicle 52 takes to reach the object 54, and the vehicle 52 takes to pass the object 54. The time until the object is reached is plotted from the difference between the minimum distance 60 of the object 54 to the zero point of the x axis and the maximum distance 62 of the vehicle 52 to the zero point of the x axis divided by the difference between the speed 56 of the vehicle 52 and the speed 58 of the object 54 in the x direction. The time until the object is passed is obtained from the difference between the maximum distance 64 of the object 54 to the zero point of the x axis and the minimum distance 66 of the vehicle 52 to the zero point of the x axis divided by the difference between the speed 56 of the vehicle 52 and the speed 58 of the object 54 in the x direction.

(20) In order to determine the trajectories 21, the position of the object 54 is predicted at both plotted times or points in time, and a trajectory 21 is determined which leads past these two positions of the object 54 and the path which the object 54 travels along between these two positions.

(21) FIG. 3b shows a region 70, in which the vehicle 52 cannot move due to detected objects 11, which region 70 therefore cannot be passed through as the trajectory 21. In this context it is assumed that the objects 11 are located on the curve 74. A region 70, which always has a distance 72 from the curve 74, that is to say from the objects 11 which corresponds to at least half the width of the vehicle 52, is defined around this curve 74. This region 70 is approximated to a smoothed (here convex) shape by means of offset straight lines during the determination.

(22) FIG. 3c shows the determination of the trajectories 21 according to an exemplary embodiment on the basis of checking points, through which cubic splines or cubic polynomial lines are made to pass. For this purpose, a unidimensional presentation of the vehicle and of the determined objects 11 is selected. FIG. 3c shows for this purpose a vehicle 80 and a detected object 82, which is illustrated here as a further parked vehicle, that is to say as a static object. The region 70 which is illustrated in FIG. 3b is illustrated around the vehicle. A travel path 84 is firstly assumed. Here, the detected object 82 constitutes an obstacle. A checking point 86 is generated thereon, at the corner of the object 82, plus a safety distance defined by the region 70. A cubic spline 88 is made to pass through this checking point 86. In its course said cubic spline 88 meets a further object 90. As before, a new checking point 92 and a new spline 94 are generated, which spline 94 passes through the second checking point 92 and therefore also passes by the second object. Smoothed trajectories 21, passages by way of which the vehicle would avoid collisions, are therefore generated.

(23) All the features specified in the above description and in the claims can be used individually or in any desired combination with one another. The disclosure of the invention is therefore not restricted to the described or claimed combination of features. Instead, all combinations of features are to be considered as being disclosed.

LIST OF REFERENCE SIGNS

(24) 10 Detection of objects 11 Detected objects 12 Prediction of positions of the objects 13 Future positions of the objects 14 Detection of movement of the driver's vehicle 16 Prediction of the travel path of the driver's vehicle 17 Predicted travel path of the driver's vehicle 18 Determination of the objects located in the travel path 19a Objects located in the travel path 19b First object located in the travel path 20 Determination of trajectories 21 Trajectories 22 Determination of danger values 23 Danger values 24 Probability value 25 Comparison of danger values with a threshold value 26 Threshold value 27 Execution of collision-avoiding measures 28 Determination of a period of time up to which braking is possible 29 Time threshold value 30 Region of normal travel of the vehicle 32 Region of signalling with a visual display 34 Region of acoustic signalling 36 Region of braking with lower braking force 38 Region of braking with higher braking force 39 Collision-avoiding measures 40 Time axis 42 Acceleration axis 44 Zero line 46 Lower braking force 48 Higher braking force 50 Progression of the execution of collision-avoiding measures 52 Vehicle 54 Detected object 56 Speed of the driver's vehicle 58 Speed of the detected object 60 Minimum distance of the object from the zero point of the x axis 62 Maximum distance of the vehicle from the zero point of the x axis 64 Maximum distance of the object from the zero point of the x axis 66 Minimum distance of the vehicle from the zero point of the x axis 70 Region which cannot be passed through 72 Distance of half the width of the vehicle 74 Curve on which objects are located 80 Vehicle 82 Detected object 84 Travel path 86 Checking point 88 Spline 90 Further object 92 Checking point 94 Spline