METHOD AND PARAMETER MODULE FOR IDENTIFYING THE TYPE AND/OR THE SEVERITY OF A COLLISION OF A VEHICLE WITH A COLLISION OBJECT

Abstract

A method for identifying the type and/or the severity of a collision of a vehicle of a first mass with a collision object of a second mass in an early phase to trigger safety measures, including: detecting surroundings data of the vehicle; identifying the collision object from the surroundings data; extracting a reference feature, not lying in a direct collision area, of the collision object; repeated successive ascertainment of an instantaneous speed of the vehicle and determining a change of the speed of the vehicle; repeated successive determination of an instantaneous relative speed between the vehicle and the reference feature and determining a change of the speed of the collision object; estimating a mass ratio, effective during the collision, between the mass of the vehicle and the mass of the collision object from the ascertained changes of the speeds of the vehicle and of the collision object.

Claims

1-10. (canceled)

11. A method for identifying the type and/or the severity of a collision of a vehicle of a first mass with a collision object of a second mass in an early phase of the collision to trigger safety measures, the method comprising: a) detecting surroundings data of surroundings of the vehicle; b) identifying the collision object from the surroundings data; c) extracting at least one reference feature, not lying in a direct collision area, of the collision object for further observation of a relative speed between the reference feature of the collision object and the vehicle; d) repeatedly successively ascertaining an instantaneous speed of the vehicle and determining a change of the speed of the vehicle; e) repeatedly successively determining an instantaneous relative speed between the vehicle and the reference feature and determining a change of the speed of the collision object; and f) estimating a mass ratio, effective during the collision, between the mass of the vehicle and the mass of the collision object from the ascertained changes of the speed of the vehicle and the ascertained changes of the speeds of the collision object.

12. The method as recited in claim 11, wherein subsequent to step f), the following steps are carried out: g) determining a degree for the type and/or the severity of the collision from a point of view of the vehicle based on the ascertained mass ratio, an initial speed of the vehicle measured before the collision, and an initial relative speed between the vehicle and the collision object; h) triggering at least one safety measure suitable for the type or severity of the collision at a point in time based on the type or severity of the collision.

13. The method as recited in claim 11, wherein the surroundings data of the surroundings are obtained by at least one of the following methods: video monitoring, and/or LIDAR monitoring, and/or radar monitoring, and/or ultrasonic monitoring.

14. The method as recited in claim 11, wherein for a potential collision object, at least one reference feature, identifiable from the surroundings data, is selected for further observation and its instantaneous relative speed with respect to the vehicle is repeatedly measured.

15. The method as recited in claim 11, wherein the instantaneous speed of the vehicle is repeatedly determined before and during a collision from sensors present in the vehicle for rotational speed, and/or speed, and/or accelerations.

16. The method as recited in claim 11, wherein an absolute mass of the collision object is also calculated from the mass ratio in the case of an approximately known mass of the vehicle, whereby kinematics of the collision are calculated, under the assumption of a plastic impact according to conservation of momentum, and is used for determining a degree of the type and/or the severity of the collision.

17. The method as recited in claim 11, wherein surroundings data of the surroundings are used in different ways or by different systems in the vehicle, in the case of a determination of an imminent collision, uses of the surroundings data being switched off which are not necessary for identifying the type and/or the severity of the collision or are not necessary for measures following from the collision.

18. The method as recited in claim 11, wherein the ascertainment of the instantaneous speed of the vehicle and the determination of the instantaneous relative speed between the reference feature and the vehicle are carried out repeatedly in identical time intervals during the collision, the change of the speed of the vehicle and the change of the speed of the collision object also being determined per time unit.

19. The method as recited in claim 11, wherein, in step c), two reference features on the collision object are extracted and observed in the subsequent steps.

20. A control unit for estimating the absolute mass of a collision object in an early phase of a collision with a vehicle, or of a ratio of a mass of a vehicle in relation to a mass of a collision object in an early phase of a collision, the control unit being assigned to a system in the vehicle for triggering suitable safety measures on safety elements during a collision, the control unit having inputs for measured values from at least one first measuring device for repeated determination of a relative speed between the vehicle and the collision object before and during the early phase of the collision, and from at least one second measuring device for repeated determination of an absolute speed of the vehicle, and the control unit being configured to estimate the mass of the collision object or the mass ratio of the vehicle and the collision object from a change of the absolute speed of the vehicle and a change of the relative speed toward the collision object in the early phase of the collision on the basis of conservation of momentum.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 schematically shows a situation shortly before a collision of a vehicle with a collision object.

[0024] FIG. 2 shows a flow chart of an example of a method according to the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0025] FIG. 1 shows in a schematic depiction a constellation shortly before the impact of a motor vehicle 1 with a collision object 2. Motor vehicle 1 has initial speed V.sub.1,0 and mass m.sub.1. The collision object, in the present case likewise depicted as a motor vehicle by way of example, has initial speed V.sub.2,0 and mass m.sub.2. Before the collision, the two collision parties have a certain distance and a spatial orientation to each other. The area directly affected by a collision (which is thereby deformed) is subsequently designated as collision area 5. Vehicle 1 has at least one first measuring device 3 for detecting surroundings data of the surroundings of vehicle 1. This is thereby typically a camera, an ultrasonic system or laser system, or a radar device. A laser scanning system is preferably used for detecting surroundings data because this may also provide, simultaneously with data about the direction of an object, data about the relative movement between vehicle 1 and collision object 2, for example, by measuring the Doppler effect.

[0026] Under favorable conditions, first measuring device 3 already provides extensive data about a potential collision object 2 already before a collision. Within the scope of the present observations, it is assumed that driving assistance systems or systems for autonomous driving, present in vehicle 1, identify potential collision objects 2 at an early state and may provide a collision prediction. If a potential collision object 2 is identified, then at least one first reference feature 4 is identified on collision object 2 with the aid of first measuring device 3 and extracted for a closer observation. Since this first reference feature 4 is to be further observed also during the collision, it should not lie in a direct collision area 5, which deforms first during a collision. A lower corner of a lateral delimitation of a windshield, a so-called A-pillar of a motor vehicle, offers a suitable reference feature. For increased accuracy of the additional measurements, a second reference feature 12, and additional reference features may also be involved, depending on the capability of the data processing in vehicle 1. In any case, the relative distance 6 between first measuring device 3 and first reference feature 4 (and naturally additional reference features) is measured quite precisely before and during a collision. This is carried out before and primarily during the collision in preferably identical time intervals. A second measuring device 9 in vehicle 1 enables it to measure the absolute speed of this vehicle at any time. A plurality of different systems may be used for this purpose. As a result, speed data V.sub.1,0, V.sub.1,1, V.sub.1,2 . . . V.sub.1,n at points in time 0, 1, 2 . . . n are available at an input 13. Likewise, information about distance 6 between first measuring device 3 and first reference feature 4 is available at control unit 7 at an input 14 for surroundings data. Data about relative speed V.sub.r,0, V.sub.r,1, V.sub.r,2 . . . V.sub.R,n is often also already available or may be calculated from the chronological sequence of these data.

[0027] A main goal of the described system is to support the safety system of vehicle 1 through additional information in the estimation of the severity of a collision, so that safety measures may be triggered in a timely manner and to a suitable extent. For estimating a collision, it is not only important to be able to estimate the geometric data of a collision sequence, for example, impact angle, impact speed, and impact point in time, but also mass m.sub.2 of collision object 2 or the ratio of mass m.sub.1 of vehicle 1 to mass m.sub.2 of collision object 2 is also of great significance. If one essentially assumes a plastic impact, then the collision parties deform in collision area 5 and both become slower in the process. Expressed simply, the mass ratio may be calculated from the difference of the speed decelerations (thus the negative acceleration of both collision parties), under the assumption, that mass m.sub.1 of vehicle 1 being known, the absolute masses of both vehicles may be calculated. However, for the progression of the collision, basically only the ratio of the two masses is important. As is subsequently explained in greater detail by way of the corresponding formulas, one may therefore calculate, from the speed deceleration of both collision parties 1, 2, in the early phase of a collision, typically in the first 10 through 100 milliseconds, which end speed V.sub.end vehicle 1 and collision object 2 will have after the collision (both ultimately have the same speed in a plastic impact) from which the load to be expected for the occupants of vehicle 1 may be better estimated. Control unit 7 therefore contributes data about the mass ratio of the collision parties to system 8 for triggering the safety measures, whereby the sequence and consequences of the collision may be more accurately estimated and safety elements triggered in a suitable way. In particular, seat belt tensioners 10 and/or air bags 11 may be triggered, for example.

[0028] FIG. 2 illustrates the progression of the method in accordance with the present invention in control unit 7. Surroundings data are forwarded from first measuring device 3 to input 14 for surroundings data, also including data for relative speed V.sub.r,n between vehicle 1 and collision object 2 at points in time 0, 1, 2 . . . n closely following each other. V.sub.r,0 is thereby the last relative speed measured before the collision, while the following speeds are measured in the early phase of the collision. Speed data are forwarded from second measuring device 9 of vehicle 1 to input 13 for speed data. These data are available for a speed determination 15, from which speeds V.sub.1,0, V.sub.1,1, V.sub.1,2 . . . V.sub.1,n at points in time 0, 1, 2, . . . n are selected or calculated. The data from a relative speed determination 16 and speed determination 15 are forwarded to an absolute speed determination 17, absolute speed V.sub.2 resulting from the difference of relative speed V.sub.r and speed V.sub.1. Speed V.sub.1,0, V.sub.1,1 . . . V.sub.1,n of vehicle 1 and speed V.sub.2,0, V.sub.2,1 . . . V.sub.2,n of collision object 2 are available in absolute speed determination 17 for each point in time t=0, 1, 2 . . . n. In an acceleration determination 18, therefore, the speed differences may be determined at every point in time t=1, 2, . . . n for the preceding point in time t=0, 1, 2 . . . n1. As needed, speed differences may be determined over longer time frames for increasing the measuring accuracy, or the individually calculated values may be analyzed at different points in time. In total, a negative acceleration results in acceleration determination 18 for both collision parties, so that, assuming the physical laws of a plastic (or at least partially plastic) impact, ratio m.sub.1/m.sub.2 of the participating masses may be estimated in a mass (ratio) determination 19. This ratio is forwarded to system 8 to trigger safety measures, whereby the mass ratio or, if mass m.sub.1 of vehicle 1 is known, both absolute masses of the collision partners may be taken into account in the considerations regarding severity S of a collision. The described calculations are carried out in a simplified depiction according to the following formulas:

V.sub.2,n=V.sub.r,nV.sub.1,n at point in time n=0,1,2 . . . n

Delta V.sub.1,n=V.sub.1,nV.sub.1,n-1 at point in time n=1,2 . . . n

Delta V.sub.2,n=V.sub.2,nV.sub.2,n-1 at point in time n=1,2 . . . n

m.sub.1*V.sub.1,0+m.sub.2*V.sub.2,0=(m.sub.1+m.sub.2)*V.sub.end

S=V.sub.1,0V.sub.end

S=m.sub.2/(m.sub.1+m.sub.2)*(V.sub.1,0V.sub.2,0)

where
V.sub.end=end speed of both collision parties after the collision
Delta=speed deceleration
S=degree of the severity of a collision

[0029] The method in accordance with the present invention enables a system for triggering safety measures in a vehicle 1 with a collision object 2 to obtain data in the early phase of a collision, which enable an estimation of the mass ratio between vehicle 1 and collision object 2, which enables a more accurate, early estimation of the consequences of the collision for the occupants of vehicle 1, whereby a better chronological adjustment and coordination of safety measures, in particular the triggering of seat adjusters, seat belt tensioners, and/or airbags, is facilitated.