DE102007015032A1 - Method for evaluating how critical driving situation is comprises calculating possible accelerations and decelerations for vehicle and object whose paths are set to cross and deducing time periods in which their paths would overlap - Google Patents

Abstract

The method for evaluating how critical a driving situation is comprises calculating possible accelerations and decelerations for a vehicle (1) and an object (2) whose paths are set to cross. Time periods in which their paths would overlap are calculated for each pair of accelerations and/or decelerations are calculated from these, allowing the criticality of the situation to be evaluated. An independent claim is included for a system for avoiding collisions or reducing their consequences using a control unit mounted on a vehicle to carry out the method and operating a driver protection system if a collision is likely to occur.

Description

The The invention relates to a method for evaluating the criticality of a Traffic situation according to the generic term of claim 1 and a device for collision avoidance or Kollisionsfolgenminderung according to the preamble of the claim 12th

to Avoiding collisions in traffic are different Collision Avoidance Systems or Vehicle Assistance Systems Known which in the forward driving range a collision zone and a approaching the collision zone and identify a collision course with your own vehicle.

From the WO 01/65520 A2 For example, a method of avoiding accidents of own vehicle (also called system vehicle) is known in which at least one lane that leads to an intersection is scanned and in which a possible collision vehicle on that lane is identified and predicted, whether the own vehicle and the potential collision vehicle will be in the intersection simultaneously, and if so predicted, a warning is issued in response to that forecasting. It is from the WO 01/65520 A2 It is known to determine the speed or acceleration of the collision vehicle and to determine the probability of an accident at the intersection, taking into account further vehicle-specific data and environmental data. In addition, current vehicle data, such as vehicle speed, are recorded for the collision vehicle.

From the EP 1 096 458 B1 In addition, there is known a system for preventing a collision at a road intersection in which actual data, in particular vehicle position data, vehicle condition data, road surface condition data is detected, and in preventing the detection of possible turning of an oncoming vehicle, the position of the other vehicle and the possibility of occurrence a collision in the intersection area are determined, wherein the possibility of the occurrence of a collision, the own vehicle is stopped.

at the known methods remain changes disregarded in the driving behavior of the other vehicle.

Of the Invention is therefore based on the object, a simple and fast Procedure for a situation-appropriate evaluation of the criticality of a traffic situation and a device using this method Specify collision avoidance or collision mitigation.

The The object is solved by the features of the independent claims. advantageous Embodiments and developments of the invention are the subject the dependent claims.

According to the invention in a method for assessing the criticality of a traffic situation from environmental data collected from one's own vehicle Become one on one intersecting collision course to your own Vehicle object identified and one on the collision course lying collision zone, and based on a detected current state of movement of the own vehicle and the object an overlap period predicted as a time domain becomes, in which the own vehicle and the object at the same time be in the collision zone. For your own vehicle and in addition or alternatively for the object also becomes several possible acceleration values a vehicle acceleration or vehicle deceleration or an object acceleration or object delay given as a parameter, and for each acceleration value pair of these acceleration values given as parameters becomes an associated overlap period predicted. The evaluation of the criticality takes place on the basis of all predicted overlap periods.

By such determination of overlap periods for different types the driving behavior of the own vehicle and the approaching one Object characterizing acceleration values, a criticality of a preceding traffic situation (= risk of collision in the collision zone) easy, fast and safe considering a possibly changing one Driving behavior of the own vehicle or the approaching one Object to be determined. It is a largely until reaching the Collision zone transparent monitoring the driving behavior of both your own vehicle and yourself approaching Vehicle possible. In particular, the criticality a traffic situation in the crossing area or in cross traffic easily and quickly determined and evaluated as well as for the triggering of Driver assistance systems are used. This can false warnings and / or false releases in Driver assistance systems are largely avoided.

there is under a collision zone, in particular a preceding Intersection of two intersecting roadways understood. Under roadways are understood in particular so-called driving hoses, within which the own vehicle or object is expected be moved, or lanes of roads on which your own Move the vehicle and the object. Depending on the vehicle's own systems can for determining a forward collision zone data of a Navigation system and / or a radar unit and / or an optical Receiving unit, e.g. a camera, and / or something called Vehicle-vehicle communication is recorded and analyzed.

When Environment data can in particular navigation data of a navigation system or data of others Vehicle sensors or data of an environment detection unit for Determination of own vehicle speed, vehicle acceleration, Vehicle delays used by steering wheel angle and / or yaw rate. Furthermore can by means of the environment detection unit and / or the further vehicle sensors and / or by means of a so-called vehicle-to-vehicle communication unit as environmental data, object characteristics of the approaching object, e.g. Location of the object to own vehicle, object speed, object acceleration, Object delay Object dimensions are determined.

When Characteristics or In addition, data of the own vehicle and the approaching object can be added also further, from one of the determined vehicle characteristics and / or Object characteristics derived and / or to these proportional characteristics of the own vehicle and / or the approaching Object, e.g. one to the beginning or end of the collision zone yet distances to Direction Distance to go (= distance of approaching Object to the beginning or end of the collision zone), one possibly displayed direction change, be determined.

in the Furthermore, for better clarity, if for both - i.e. for the own vehicle and the object - the Characteristic values are determined, which are referred to as acceleration and deceleration. Specifically, the acceleration and deceleration of the vehicle becomes vehicle acceleration or vehicle deceleration and the acceleration and deceleration of the object called object acceleration or object delay.

In An advantageous development of the invention are for the vehicle and the object determines a respective entry time duration, which the entry of the vehicle or the object, i. entering this with the respective front, represented in the collision zone, and determining a respective exit time duration which is the exit of the vehicle or object, i. the leakage of this with her Rear, represented from the collision zone. The prediction the overlap periods takes place then on the basis of this for the respective acceleration value pair ascertained admission and Discharge durations.

Preferably be for the own vehicle and / or the object a first remaining time determined as the time span remaining until a time to a full stop at the latest must be initiated to the own vehicle or the object decelerate to a stop before reaching the collision zone and / or a second remaining time period is determined as a time span which remains until a time at which an evasive maneuver no later than must be initiated to the own vehicle or the object to bring to a collision zone circulating course, and / or a third remaining time period is determined as a time span which lasts until one Time remains at the latest a maximum acceleration must be initiated to your own Vehicle or the object in time to remove from the collision zone. The evaluation of the criticality takes place under consideration of at least one of these remaining time periods.

dT

den für das jeweilige Beschleunigungswertepaar berechneten Überlappungszeitabstand darstellt,

T2₁

die für das eigene Fahrzeug und den jeweiligen Beschleunigungswert prädizierte Austrittszeitdauer darstellt,

T2₂

die für das Objekt und den jeweiligen Beschleunigungswert prädizierte Austrittszeitdauer darstellt,

T1₁

die für das eigene Fahrzeug und den jeweiligen Beschleunigungswert prädizierte Eintrittszeitdauer darstellt und

T1₂

die für das Objekt und den jeweiligen Beschleunigungswert prädizierte Eintrittszeitdauer darstellt.

Preferably, the overlap periods for each acceleration value pair of the acceleration values given as parameters are calculated according to the following equation: dT = Mini {T2 1 , T2 2 } - Max {T1 1 , T1 2 } in which

dT

represents the overlap time interval calculated for the respective acceleration value pair,

T2 ₁

represents the exit time period predicted for the own vehicle and the respective acceleration value,

T2 ₂

represents the exit time period predicted for the object and the respective acceleration value,

T1 ₁

represents the entry time duration predicted for the own vehicle and the respective acceleration value, and

T1 ₂

represents the entry time duration predicted for the object and the respective acceleration value.

In An advantageous development of the method is the traffic situation evaluated as uncritical if the overlap period for an actual acceleration value pair, that of a detected instantaneous vehicle acceleration or vehicle deceleration and corresponds to a detected instantaneous object acceleration or object delay, is negative.

Preferably the traffic situation is considered critical if the overlap periods for all Acceleration value pairs from a given surrounding area the actual acceleration value pair is positive, the traffic situation advantageously evaluated as very critical if each of the determined overlap periods positive is, i. also the overlap periods, the for acceleration value pairs have been identified outside the predetermined environmental range and thus far away to the Actual acceleration value pair lie.

Of the predetermined environmental range is preferably based on limits defined for the Vehicle acceleration or vehicle deceleration and the object acceleration or object delay are given, with the specification of the limits advantageously dependent on the object type of the object. This will take into account the Combinations of the acceleration value pairs to the object type (e.g. Truck, passenger car, motorcycle etc.), so that's different acceleration and deceleration capabilities the different object types in the evaluation of the traffic situation considered becomes.

In an advantageous embodiment of the method is at a as critically evaluated traffic situation an optical, acoustic and / or haptic driver warning issued to the driver of the own vehicle. This is a user of the vehicle in a simple way and Display a critical collision hazard level. Thus, can the driver of the vehicle himself by appropriate measures, e.g. stronger Braking or accelerating your own vehicle, the risk of collision counteract. About that In addition, the driver of the vehicle can be actuated by actuating e.g. optical or acoustic signaling equipment, the object approaching a collision course, e.g. another vehicle, to attract attention.

In Another advantageous development is critical in one evaluated traffic situation depending on at least one the remaining time a driver assistance system for collision avoidance or Collision mitigation is activated or it becomes an intervention threshold the driver assistance system adapted to the criticality of the traffic situation. In particular, therefore, a brake assist function of the driver assistance system be activated, for example, a braking torque to delay the own vehicle targeted to adjust such that the own vehicle arrives in time before reaching the collision zone.

A inventive device for collision avoidance or collision mitigation an environment detection unit for detecting the environment of a equipped with the device own vehicle, a control device for performing the inventive method steps dependent on the detected environment and provide an evaluation signal as a result of the performed Procedural steps and a driver assistance system for performing a collision avoiding or collision sequence reducing engagement dependent on of the control unit provided evaluation signal.

Preferably the environment detection unit comprises a radar unit and an optical recording unit.

The Invention will now be described with reference to an embodiment with reference closer to the figures explained. Showing:

1 schematically an intersection of two lanes with a possible collision zone annä hernder objects, such as a separate vehicle and on the road of the own vehicle intersecting roadway and thus the collision zone approaching object,

2 schematically a device for collision avoidance or collision mitigation and

3 : various case studies for the assessment of the risk of collision.

each other corresponding parts are in all figures with the same reference numerals Mistake.

1 schematically shows an intersection K of two intersecting roadways F1 and F2 with a possible collision zone Z for a first approaching on the roadway F1 object 1 and a second object approaching the road F2 2 , In this case, the lanes F1 and F2 are in particular so-called driving hoses or predicated object movement lanes, each of which represents a geometric location area defined by a left and right boundary line and determined in a forward-looking manner, that of the respective object 1 . 2 is likely to be claimed while traveling. Of course, the lanes F1, F2 may also be traffic lanes of roads on which the objects are 1 . 2 to move towards each other. The lanes can be determined in a conventional manner by recognizing lane markers and / or by means of a navigation system based on digital road maps.

In the approaching the collision zone Z objects 1 and 2 For example, it is a vehicle traveling on the roadway F1 (= first object 1 , will be further explained as a separate vehicle 1 and a second object traveling on the road F2 2 (= the collision zone Z on the lane F1 of the own vehicle 1 cruising road F2 approaching vehicle; in the following as an approaching object 2 designated). The xy coordinate system is in the direction of travel of the vehicle 1 seen at the front right corner of the vehicle 1 shown. The in the direction of travel of the object 2 lying front left corner is thus relative to the vehicle 1 at the point [x ₁ , -y ₂ ]. The vehicle 1 and the object 2 Drive straight ahead and at right angles to each other with a vehicle speed v ₁ and an object speed v ₂ toward each other. When the vehicle 1 and the object 2 at the same time in the collision zone Z, a collision can occur.

For determining and estimating a possible risk of collision in the collision zone Z for the own vehicle 1 this includes a device 3 for the evaluation of the criticality of a traffic situation ahead, ie for the prognosis of a threat to own vehicle 1 due to the traffic situation ahead.

The device 3 includes, for example, one already in the vehicle 1 existing control unit 4 , in particular a brake control unit, an engine control unit or a separate control unit, in which the method for the evaluation of the criticality described below is implemented. In addition, other control and / or regulation methods, such as engine control, brake control, in the device 3 be implemented.

For forecasting the criticality of the traffic situation by determining the driving behavior of the object approaching the collision zone Z 2 and / or the driving behavior of one's own vehicle 1 be the controller 4 Data, parameters and / or characteristics of various detection devices, as exemplified in the 2 is shown fed: environmental data U, eg a A of the object 2 , the intersection K and / or the carriageway F1, at least one optical receiving unit 5 , Navigation data N of a navigation system 6 , eg position data P, vehicle speed v _{1 of} the own vehicle 1 , Road data S on road type and / or type of crossing K, temperature values T of a temperature sensor 7 for the ambient temperature T _U and / or the temperature T _F1 above the road F1, radar data R a radar unit 8th , eg vehicle speed v _{1 of} the own vehicle 1 , Object velocity v _{2 of} the approaching object 2 , Distance x ₁ of your own vehicle 1 to the collision zone Z (also called the vehicle distance x ₁ ), distance y _{2 of} the approaching object 2 to the collision zone Z (also called object distance y ₁ ), data D of a vehicle-to-vehicle communication unit 9 , eg object velocity v ₂ or object type O of the approaching object 2 , Depending on the structure and / or type of the respective detection unit, such as the recording unit 5 , of the navigation system 6 , the temperature sensor 7 , the radar unit 8th , the vehicle-to-vehicle communication unit 9 can each by means of the same and / or by means of the control unit 4 Further parameters, data, parameters and / or values from the determined data, parameters and / or characteristics determined, in particular derived from these. In addition, to determine the criticality of the traffic situation ahead and the driving behavior of the approaching object 2 and of your own vehicle 1 Further data, characteristic values and / or parameters are used: Type-related acceleration values a ₁ , a ₂ , type-related braking distance values s ₁ , s ₂ and / or type-related deceleration values b ₁ , b ₂ . Under type-related characteristic values are understood in particular various types of vehicles, such as trucks, passenger cars or motorcycles, associated characteristics. These values may be from another vehicle system, eg the vehicle-vehicle communication unit 9 , be supplied and / or alternatively in the control unit 4 be deposited.

In operation of the vehicle 1 is while driving by means of the control unit 4 Based on environmental data U and / or navigation data N, the approach of the vehicle 1 identified at an intersection K and a possible collision zone Z. In addition, by means of the control unit 4 For example, based on the radar data R for the preceding vehicle environment determines whether an object 2 on the intersecting roadway F2 approaches the collision zone Z. If this is the case, then by means of the control unit 4 the driving behavior of the approaching object 2 and your own vehicle 1 certainly. In this case, the instantaneous object speed v _{2 of} the object 2 , the instantaneous object acceleration a ₂ or object delay b _{2 of} the object 2 and its current object distance y ₂ to the collision zone Z the controller 4 supplied or determined by this on the basis of supplied radar data R. Alternatively or additionally, the environmental data U of the optical recording unit 5 be taken into account for determining the object speed v ₂ and the object distance y ₂ to the collision zone Z. In particular, the radar data R and environmental data U can be fused to the instantaneous object-relevant characteristics of the object 2 how to determine the object acceleration a ₂ or object delay b ₂ , the object speed v ₂ and the object distance y ₂ .

In addition, for your own vehicle 1 its current or instantaneous vehicle acceleration a ₁ or vehicle deceleration b ₁ , as well as its instantaneous vehicle speed v ₁ and the instantaneous vehicle distance x ₁ to the collision zone Z determined as parameters.

Based on the for your own vehicle 1 and for the object 2 determined parameters (vehicle / object acceleration or deceleration, vehicle / object distance, vehicle / object speed) is at least one situation-specific time period T1 ₁ to Tn ₁ for the own vehicle 1 and a situation-specific time period T1 ₂ to Tn ₂ for the object 2 certainly.

Thus, as a first time period T1 ₁ or T1 _2, the respective entry time period until the entry of the vehicle 1 with its front in the collision zone Z or until the entry of the object 2 understood with its front in the collision zone Z (hereinafter entry time T1 _{1 of} the vehicle 1 or entry time T1 _{2 of} the object 2 with T1 also referred to as TTE = time-to-enter or TTZ = time-to-zone).

Furthermore, as a second time duration T2 ₁ or T2 _2, the respective exit time duration until the vehicle exits 1 with its tail from the collision zone Z or until the exit of the object 2 understood with his tail from the collision zone Z (hereinafter exit period T2 _{1 of} the vehicle 1 or entry time T2 _{2 of} the object 2 also called T2 as TTL = time-to-leave or TTD = time-to-disappear).

In addition, further time periods T3 ₁ to Tn ₁ or T3 ₂ or Tn ₂ can be determined.

As a third time period T3 ₁ or T3 ₂ , for example, the respective residence time of the vehicle 1 in the collision zone Z or the object 2 in the collision zone Z understood (hereinafter dwell time T3 _{1 of} the vehicle 1 or residence time T3 _{2 of} the object 2 called). The residence time T3 ₁ , T3 _{2 of} the own vehicle 1 or the object 2 correspond to the difference between each for the own vehicle 1 or the object 2 determined exit time period and entry time period.

As a fourth time period T4 ₁ or T4 ₂ , for example, in each case a first, until the exercise of a maximum delay (= full braking) for timely stop before the collision zone Z remaining time remaining of the vehicle 1 or the object 2 understood (hereinafter the first remaining time T4 _{1 of} the vehicle 1 or first remaining time T4 _{2 of} the object 2 called T4 also called TTB = time-to-break). The first remaining time T4 ₁ , T4 ₂ thus corresponds to a period of time, the driver of the vehicle 1 or of the object remains at most, in order by a full braking the vehicle 1 or object 2 slow down to a stop before reaching the collision zone Z.

As a fifth time period T5 ₁ or T5 ₂ , for example, in each case a second, until the avoidance to avoid a collision in the collision zone Z remaining time remaining of the vehicle 1 or the ob jektes 2 understood (hereinafter second remaining time T5 _{1 of} the vehicle 1 or second remaining time T5 _{2 of} the object 2 called T5 also called TTS = time-to-steer). The second remaining time T5 ₁ , T5 ₂ thus corresponds to a period of time, the driver of the vehicle 1 or the object 2 at most remains to bypass the collision zone Z by a steering wheel operation.

As a sixth time period T6 ₁ or T6 ₂ , for example, in each case a third, until the exercise of a maximum acceleration (= full throttle) for timely leaving the collision zone Z remaining time remaining of the vehicle 1 or the object 2 understood (hereinafter third remaining time T5 _{1 of} the vehicle 1 or third remaining time T5 _{2 of} the object 2 called T4, also known as TTK = time-to-kickdown). The third remaining time T6 ₁ , T6 ₂ thus corresponds to a time lapse, the driver of the vehicle 1 or the object 2 at most remains to request by a maximum acceleration, the vehicle 1 or the object 2 to the extent that it has left the collision zone Z in time before the potential collision partner (Object 2 or vehicle 1 ) enters the collision zone Z.

Furthermore can further periods of time T7 to Tn are predetermined and determined.

following becomes the method according to the invention based on different driving situations at different speeds v and accelerations a and delays b described.

Table 1 shows various determined values for the entrance time T1 ₂ and the exit time T2 _{2 of} the object 2 as a function of various acceleration values of the object acceleration a ₂ specified as parameters: Table 1 a ₂ [m / s ² ] of the objects2 +3.0 +1.0 0.0 -0.5 -2.0 -10.0 T1 ₂ [s] 1.0 1.2 1.5 2.0 3.0 ∞ T2 ₂ [s] 1.4 1.6 1.9 2.5 3.5 ∞

Table 2 shows various determined values for the entrance time T1 ₁ and the exit time T2 _{1 of} the vehicle 1 as a function of various acceleration values of the vehicle acceleration a ₁ given as parameters: Table 2 a ₁ [m / s ² ] of the vehicle 1 +3.0 +1.0 0.0 -0.5 -2.0 -10.0 T1 ₁ [s] 0.9 1.1 1.4 1.8 2.5 4.0 T2 ₁ [s] 1.3 1.5 1.8 2.3 2.9 4.6

Alternatively or additionally, the entry time periods T1 ₁ , T1 ₂ and the exit time periods T2 ₁ , T2 ₂ as a function of the delay b ₁ or b _{2 of} the vehicle 1 or the object 2 be determined. The magnitudes acceleration and deceleration are equivalent to each other and differ from each other only by the sign.

The time values "∞" describe in the tables the state in which the vehicle 1 or the object 2 before or in the collision zone Z comes to a halt. Alternatively or additionally, the residence time periods T3 ₁ and T3 ₂ can be determined. It is also possible to specify limiting values for the acceleration a ₁ , a ₂ , the deceleration b ₁ , b ₂ and / or the periods T1 _1/2 to Tn _1/2 .

• – Ist-Beschleunigung (= erfasste momentane Beschleunigung des Fahrzeugs 1 bzw. des Objekts 2),
• – Null-Beschleunigung (= konstante Fahrzeuggeschwindigkeit v₁ bzw. Objektgeschwindigkeit v₂),
• – Maximalbeschleunigung (= Vollgas, a₁ > a_Grenz1, a₂ > a_Grenz1, mit a_Grenz1 > 3 m/s²),
• – Leichte Beschleunigung (a_Grenz2 < a₁ < a_Grenz1 a_Grenz2 < a₂ < a_Grenz1 mit a_Grenz1 = 3 m/s² und a_Grenz2 = 1 m/s²),
• – Leichte negative Beschleunigung, z.B. durch Motorbremsung und Nichtbetätigung des Gaspedals (a_Grenz4 < a₁ < a_Grenz3, a_Grenz4 < a₂ < a_Grenz3, mit a_Grenz3 = –0,25 m/s² und a_Grenz4 = –1,0 m/s²),
• – Negative Beschleunigung, z.B. durch Betätigung des Bremspedals (a₁ < a_Grenz5, a₂ < a_Grenz5, mit a_Grenz5 = Ca. –2,0 m/s²),
• – Maximale negative Beschleunigung, z.B. durch Vollbremsung (a₁ < a_Grenz6, a₂ < a_Grenz6, mit a_Grenz6 = ca. –10,0 m/s²),

Alternativ können Bereiche für die Verzögerungen b₁ bzw. b₂ vorgegeben werden. Auch können weitere Unterteilungen vorgenommen werden, wodurch die Prognostizierung der Gefährdung der Verkehrssituation feinstufiger unterteilt wird. Zusätzlich können geringfügig von der Ist-Beschleunigung abweichende Beschleunigungswerte (z.B. a₁ ± 1 m/s², a₂ ± 1 m/s²) vorgegeben werden. Auch können die Werte nur für das Fahrzeug 1 bzw. nur für das Objekt 2 oder für beide vorgegeben werden.Conveniently, following acceleration values, for example, set as a parameter, and the calculation of the respective acceleration value a _1, a ₂ associated entry time durations Ti _1, T1 ₂ and exit time durations T2 _1, T2 ₂ used:

• - Actual acceleration (= detected instantaneous acceleration of the vehicle 1 or the object 2 )
• Zero acceleration (= constant vehicle speed v ₁ or object speed v ₂ ),
• Maximum acceleration (= full throttle, a ₁ > a _{limit 1} , a ₂ > a _{limit 1} , with a _{limit 1} > 3 m / s ² ),
• - Light acceleration (a _limit2 <a ₁ <a _limit1 a _limit2 <a ₂ <a _limit1 with a _limit1 = 3 m / s ² and a _limit2 = 1 m / s ^2),
• - Slight negative acceleration, eg due to engine braking and non- _{activation of} the accelerator pedal (a _Border4 <a ₁ <a _Border3 , a _Border4 <a ₂ <a _Border3 , with a _Border3 = -0.25 m / s ² and a _Border4 = -1, 0 m / s ² ),
• - Negative acceleration, eg by pressing the brake pedal (a ₁ <a _border5 , a ₂ <a _border5 , with a _border5 = about -2.0 m / s ² ),
• - Maximum negative acceleration, eg by full braking (a ₁ <a _Grenz6 , a ₂ <a _Grenz6 , with a _Grenz6 = ca. -10.0 m / s ² ),

Alternatively, ranges for the delays b ₁ and b _{2 can be} specified. Also, further subdivisions can be made, whereby the prognosis of the threat to the traffic situation is subdivided more finely. In addition, slightly different acceleration values than the actual acceleration (eg a ₁ ± 1 m / s ² , a ₂ ± 1 m / s ² ) can be specified. Also, the values can only be for the vehicle 1 or only for the object 2 or for both.

To assess the criticality of the traffic situation, first the entry time periods T1 ₁ , T1 ₂ and the exit time periods T2 ₁ , T2 _{2 of} the own vehicle 1 and the object 2 for the current states of motion of the vehicle 1 and the object 2 calculated on the basis of the detected actual acceleration values of the vehicle or object acceleration or vehicle or object deceleration. Based on these values, a rough estimate of a possible hazard situation and thus a possible collision is made in accordance with Table 3 below: Table 3

For the subsequent fine determination will be for your own vehicle 1 and the object 2 the entry and exit time durations are respectively calculated for the acceleration values a ₁ , a ₂ specified as parameters and correlated with each other, as shown by way of example in FIG 3 is illustrated in more detail by means of different cases 1a) to 4). In this case, the cases 1a) to 2b) show critical collision risk levels, ie both the object 2 as well as the vehicle 1 are simultaneously in the collision zone Z for a determined period of time, so that it could come to a collision. In cases 3) and 4), there is no simultaneous residence of the object 2 and the vehicle 1 in the collision zone Z, so that these cases represent 3) and 4) non-critical collision hazard levels.

The criticality is thus measured on the basis of the overlap period dT, which represents the time range in which the own vehicle 1 and the object 2 be in the collision zone Z at the same time. The overlap period dT corresponds to that in 3 shown examples of the difference between the shorter of the two exit durations T2 ₁ , T2 ₂ and the longer of the two entry periods T1 ₁ , T1 _second That is, the overlap period dT can be calculated as follows: dT = Min {T2 1 , T2 2 } - Max {T1 1 , T1 2 }

• – dT den berechneten Überlappungszeitabstand,
• – T2₁ die für das eigene Fahrzeug (1) prädizierte Austrittszeitdauer,
• – T2₂ die für das Objekt (2) prädizierte Austrittszeitdauer,
• – T1₁ die für das eigene Fahrzeug (1) prädizierte Eintrittszeitdauer und
• – T1₂ die für das Objekt (2) prädizierte Eintrittszeitdauer.

Represent this

• DT the calculated overlap time interval,
• - T2 ₁ for own vehicle ( 1 ) predicted exit time duration,
• T2 ₂ the for the object 2 ) predicted exit time duration,
• - T1 ₁ for own vehicle ( 1 ) predicted entry time duration and
• T1 ₂ for the object ( 2 ) predicted entry time period.

The entry and exit periods are dependent on the respective acceleration value, which is for the movement of the own vehicle 1 or the object 2 the prediction has been based.

For each acceleration value pair a ₁ , a ₂ that for the own vehicle 1 and the object 2 Acceleration values given as parameters are given their own overlapping period dT, as is indicated by way of example in Table 4 below (for the sake of clarity, only: Table 4

In The table is for clarity half are just a few values for the overlap period dT registered and the rest indicated by dots.

A positive overlap period dT> 0 means that both the own vehicle 1 as well as the object 2 at the same time in the collision zone Z and thus there will be a collision if the own vehicle 1 and the object 2 their movement will continue according to the associated acceleration value a ₁ , a ₂ . A negative overlap period dT <0 indicates what time the own vehicle is 1 and the object 2 will miss, and thus that there is an uncritical traffic situation for a movement corresponding to the associated acceleration value pair.

To assess the criticality of the traffic situation, those for the own vehicle 1 and the object 2 determined instantaneous actual acceleration values a ₁ , a ₂ (marked in bold) and further acceleration value pairs in a given surrounding area of the actual acceleration values (bold framed area) and the overlap periods dT associated with the acceleration value pairs from this area are selected and evaluated. The predetermined environmental range can be based on predetermined Defined limit values of the vehicle or object acceleration, for example, this may be acceleration limits of about +1.0 m / s ² and -2 m / s ² , which limit an acceleration range, which is usually still considered by a driver of a vehicle comfortable becomes.

If one of the overlap periods dT has a negative sign from the given surrounding area, then there is the possibility of a collision by a change of the movement state of the own vehicle corresponding to the associated acceleration value pair a ₁ , a ₂ 1 and / or object 2 to prevent. The traffic situation is therefore rated as uncritical. Otherwise, the traffic situation is assessed as critical. The traffic situation is evaluated as particularly critical if all overlap periods dT have a positive sign.

The evaluation is based on the assumption that a traffic situation is all the more critical, the farther away is an acceleration value pair a ₁ , a ₂ with a negative overlap period dT from which the current state of motion of the vehicle 1 and the object 2 characterizing actual acceleration value pair (marked in bold). This assumption is justified because the likelihood that the driver of his own vehicle 1 or the object 2 the traffic situation has been misjudged, the higher the higher the acceleration change required for a collision avoidance. By considering the overlap periods dT in the vicinity of the actual acceleration value pair, it is therefore possible to check whether a collision by accelerating or decelerating the own vehicle 1 and / or the object 2 can be avoided and if necessary to estimate the type (acceleration or deceleration) and strength of the intervention required for a hazard prevention anticipatory and thus to assess the criticality of the traffic situation.

In the example according to Table 3, a negative overlap period dT is obtained even with a slight deceleration (a ₁ <-2.0 m / s ² ) of the own vehicle 1 or with a slight deceleration (a ₂ <-2.0 m / s ² ) of the object 2 , The traffic situation is therefore rated as uncritical.

In the case of a traffic situation evaluated as critical the driver assistance system will 10 a visual, audible and / or haptic driver warning to the driver of the vehicle 1 issued to alert him to the danger situation. It can be checked before issuing the driver warning, if the driver of his own vehicle 1 has already taken appropriate measures for collision avoidance, eg actuation of the brakes. If such measures are omitted, the driver warning is output, otherwise the output of the driver warning is suppressed. Also conceivable is an output of the warning to the outside to the driver of the object 2 to indicate the risk of collision.

Alternatively or additionally, the driver assistance system 10 in the event of a traffic situation assessed as critical, a collision-avoiding or collision-sequence-reducing system intervention is triggered or an intervention threshold for such a system intervention is adapted to the criticality of the traffic situation. The system intervention may in particular be an intervention in the drive control or in a braking system of the own vehicle 1 act to the vehicle 1 to accelerate so far that it has passed through the collision zone Z, before the object 2 enters the collision zone, or around the vehicle 1 delay so far that it comes to a stop before reaching the collision zone Z. Also conceivable is an intervention in a steering system of one's own vehicle 1 to bring this to a collision zone Z circulating course.

The triggering of the system intervention may additionally depend on the fulfillment of further triggering conditions, for example falling below certain time thresholds for one's own vehicle 1 and / or for the object 2 determined first remaining time T4 ₁ , T4 ₂ and / or second remaining time T5 ₁ , T5 ₂ and / or third remaining time T6 ₁ , T6 ₂ and / or depending on the extent of driver-side brake pedal operation or accelerator pedal operation.

In particular, the driver assistance system 10 perform a brake assist function to apply a brake pressure to decelerate the vehicle in response to a driver-side brake pedal application 1 so far as to increase that vehicle 1 just before reaching the collision zone Z is braked to a standstill, if the requested by the driver's brake pedal actuation brake pressure is not sufficient and if it has been recognized in advance that the traffic situation is critical and that for the vehicle 1 and for the object 2 determined first remaining time durations T4 ₁ , T4 ₂ have each fallen below a predetermined threshold. It is also conceivable, in particular, to trigger the braking intervention independently of a driver-side brake pedal actuation, as soon as it has been recognized that the traffic situation is critical and that for the own vehicle 1 and the object 2 determined first and second remaining time periods T4 ₁ , T4 ₂ , T5 ₁ , T5 ₂ have each fallen below a predetermined threshold.

The required for a timely shutdown vehicle deceleration b ₁ or for a timely leaving the collision zone Z required vehicle acceleration a ₁ assuming optimal environmental conditions (eg sufficiently high coefficient of friction) can be determined and upon detection of a changed road condition (road wet, risk of black ice) the changed environmental conditions are adapted.

Also can Data about the collision zone, e.g. Traffic light controlled intersection and right of way regulations and / or Data about the traffic collected as environmental data and in the evaluation the traffic situation become.

Furthermore, it is conceivable for the object 2 on the basis of the environment data U, for example by pattern recognition of recorded environmental images, and / or on the basis of the radar data R an identification of the object type, eg according to the types of trucks, passenger cars, motorcycles, etc., make and that for the object 2 Determine acceleration values a ₂ as parameters as a function of the identified object type. The range of values for the acceleration values a ₂ can thus be adapted to the object type, thus achieving a situation-appropriate evaluation of the criticality.

Furthermore, it is conceivable to use derived or proportional variables instead of the acceleration values a ₁ , a ₂ specified as parameters, such as, for example, distances tabulated over the speed to the beginning or end of the collision zone Z.

Also, the method is not on the in 1 shown case of a right-angled approach between vehicle 1 and object 2 limited. The approach can also be done at any angle. It is only essential that the collision zone Z can be determined.

In the event that more than one object 2 to move to the collision zone Z, the inventive method can be performed in parallel or sequentially for all other objects. The criticality of the traffic situation is then measured on that of the objects for which the highest overlap period dT has been determined.

Further, the dimensions, such as lengths l ₁ , l ₂ and width B ₁ , B _{2 of} the vehicle 1 and the object 2 be taken into account in the determination of the entry and exit time periods T1 ₁ , T1 ₂ , T2 ₁ , T2 ₂ and the overlap durations dT determined therefrom.

Furthermore, it is conceivable that in the collision zone possibly occurring accident or collision hazard and thus the criticality of the traffic situation in dependence on the required for a collision avoidance acceleration value pairs a ₁ , a ₂ and preferably also taking into account the driver of the own vehicle 1 or the object 2 for a collision avoiding intervention remaining time periods to divide into different levels of danger, for example, in a non-critical, critical, supercritical collision risk level. The triggering of the driver warning or the activation of the driver assistance system 10 or the adaptation of the engagement threshold of the driver assistance system 10 can then be made depending on the determined risk of collision hazard.

Claims (13)

Method for assessing the criticality of a traffic situation in which environmental data (U) obtained from a separate vehicle ( 1 ) on an intersecting collision course with your own vehicle ( 1 ) object ( 2 ) and a collision zone (Z) lying on the collision course are determined, and in which based on a detected current state of motion of the own vehicle ( 1 ) and the object ( 2 ) an overlapping period (dT) is predicted as the time range in which the own vehicle ( 1 ) and the object ( 2 ) are simultaneously in the collision zone (Z), characterized in that for the own vehicle ( 1 ) and / or the object ( 2 ) a plurality of possible acceleration values of a vehicle acceleration (a ₁ ) or vehicle deceleration (b ₁ ) or an object acceleration (a ₂ ) or object deceleration (b ₂ ) are specified as parameters such that for each acceleration value pair of the acceleration values predetermined as parameters an associated overlap period (dT) is predicted, and that all predicted overlap periods (dT) are based on the criticality score. Method according to Claim 1, characterized in that the prediction of the overlap periods (dT) is based on the prediction of entry time durations (T1 ₁ , T1 ₂ ) as the time until the vehicle enters the vehicle ( 1 ) or the object ( 2 ) in the collision zone (Z) and on the prediction of exit time durations (T2 ₁ , T2 ₂ ) as time periods until the exit of the own vehicle ( 1 ) or the object ( 2 ) from the collision zone (Z). Method according to claim 1 or 2, characterized in that for the own vehicle ( 1 ) and / or the object ( 2 ) a first remaining time duration (T4 ₁ , T4 ₂ ) is determined as the time remaining until a time at which a full braking has to be initiated at the latest to the own vehicle ( 1 ) or the object ( 2 ) to decelerate before reaching the collision zone (Z) to a standstill, and / or a second remaining time (T5 ₁ , T5 ₂ ) is determined as the time remaining until a time at which an evasive maneuver must be initiated at the latest to the own vehicle ( 1 ) or the object ( 2 ), and / or a third remaining time period (T6 ₁ , T6 ₂ ) is determined as a time period which remains until a time at which a maximum acceleration has to be initiated at the latest Vehicle ( 1 ) or the object ( 2 ) in time from the collision zone (Z), and that at least one of these remaining time periods (T4 ₁ , T4 ₂ , T5 ₁ , T5 ₂ , T6 ₁ , T6 ₂ ) is taken into account in the evaluation of the criticality. Method according to claim 2 or 3, characterized in that the overlap periods (dT) for each acceleration value pair of the acceleration values predetermined as parameters are calculated according to the following equation dT = Min {T2 1 , T2 2 } - Max {T1 1 , T1 2 } where dT represents the overlap time interval calculated for the respective acceleration value pair, T2 ₁ that for the own vehicle ( 1 ) and the respective acceleration value is predicted exit time duration, T2 ₂ that represents the object ( 2 ) and the respective acceleration value predicted exit time duration represents, T1 ₁ for the own vehicle ( 1 ) and the respective acceleration value is predicted entry time duration and T1 _{2 represents} that for the object ( 2 ) and the respective acceleration value predicted entry time duration. A method according to claim 4, characterized in that the traffic situation is evaluated as uncritical if the overlap period (dT) for an actual acceleration value pair that of a current vehicle acceleration (a ₁ ) or vehicle deceleration (b ₁ ) and a current object acceleration (a ₂ ) or object delay (b ₂ ) is negative. Method according to claim 5, characterized in that that the traffic situation is assessed as critical if the overlap periods (dT) for all Acceleration value pairs from a given surrounding area of the actual acceleration value pair are positive. A method according to claim 6, characterized in that the predetermined surrounding area is defined on the basis of predetermined limit values for vehicle acceleration (a ₁ ) or vehicle deceleration (b ₁ ) and object acceleration (a ₂ ) or object deceleration (b ₂ ). Method according to claim 7, characterized in that for the object ( 2 ) whose object type is identified and that the limit values for the object acceleration (a ₂ ) or object delay (b ₂ ) are specified as a function of the object type. Method according to one of claims 6 to 8, characterized that the traffic situation is rated as very critical if each of the determined overlap periods (dT) is positive. Method according to one of claims 1 to 9, characterized that in a traffic situation assessed as critical, an optical, acoustic and / or haptic driver warning is issued. Method according to one of claims 3 to 10, characterized in that at a be as critical be evaluated traffic situation as a function of at least one of the remaining time periods (T4 ₁ , T4 ₂ , T5 ₁ , T5 ₂ , T6 ₁ , T6 ₂ ) a driver assistance system ( 10 ) is activated for collision avoidance or collision sequence reduction or an intervention threshold of the driver assistance system ( 10 ) is adapted to the criticality of the traffic situation. Contraption ( 3 ) for collision avoidance or collision mitigation with an environment detection unit for detecting the environment of a device ( 3 ) own vehicle ( 1 ), characterized by a control device ( 4 ) for carrying out the method steps according to one of the preceding claims as a function of the detected environment and for providing an evaluation signal as a result of the method steps performed and with a driver assistance system ( 10 ) for performing collision avoiding or collision sequence reducing engagement depending on the evaluation signal provided by the controller. Apparatus according to claim 12, characterized in that the environment detection unit comprises a radar unit ( 8th ) and an optical recording unit ( 5 ).