Method for determining the severity of a possible collision between a motor vehicle and another vehicle, control apparatus, driver assistance system and a motor vehicle

Abstract

A method for determining the severity of a possible collision between a motor vehicle and another vehicle is disclosed. Sensor data which describes the other vehicle is received from at least one sensor of the motor vehicle by means of a control apparatus, a change in velocity which describes a difference between a velocity (V1) of the motor vehicle before the collision and a collision velocity (Vc) of the motor vehicle (1) after the collision is determined on the basis of the sensor data, and the severity of the possible collision is determined on the basis of the determined change in velocity, wherein a mass (m2) of the other vehicle is estimated by means of the control apparatus on the basis of the sensor data, and the severity of the possible collision is additionally determined on the basis of the estimated mass (m2).

Claims

1. A method for protecting vehicle occupants in a potential collision between a motor vehicle and another vehicle, comprising: receiving sensor data which describes the another vehicle from at least one sensor of the motor vehicle; determining a maximum steering lock of the another vehicle based on sensor data; determining a multiplicity of impact areas on the another vehicle and a probability of impact for each of the multiplicity of impact areas; determining a change in velocity which describes a difference between a velocity (V.sub.1) of the motor vehicle before the collision and a collision velocity (V.sub.c) of the motor vehicle after the collision based on the sensor data; determining a severity of a possible collision based on the determined change in velocity; releasing a brake of the motor vehicle when the determined severity exceeds a first threshold value; actuating a belt pretensioner when the determined severity exceeds a second threshold value; and pivoting at least one part of a headrest of a vehicle when the determined severity exceeds a third threshold value, wherein the headrest is pivoting based on the probability of impact for each of the determined multiplicity of impact areas, and wherein the probability of impact for each of the determined multiplicity of impact areas is determined based on the maximum steering lock and a probability distribution function, and wherein a mass of the another vehicle is estimated by a control apparatus based on the sensor data, and wherein the severity of the possible collision is additionally determined based on the estimated mass.

2. The method according to claim 1, wherein the sensor data describes at least one outer surface of the another vehicle wherein external dimensions of the another vehicle are determined based on the sensor data, and the mass of the another vehicle is estimated based on the determined external dimensions of the another vehicle.

3. The method according to claim 1, wherein the another vehicle is assigned to a predetermined vehicle class based on the sensor data, and the mass of the another vehicle is determined based on the predetermined assigned vehicle class.

4. The method according to claim 1, wherein the velocity (V.sub.1) of the motor vehicle before the collision and/or a mass of the motor vehicle are/is determined, and the severity of the possible collision is determined based on the determined velocity (V.sub.1) and/or the mass of the motor vehicle.

5. The method according to claim 1, wherein the mass of the another vehicle which is located behind the motor vehicle in a direction of travel of the motor vehicle is determined.

6. The method according to claim 1, wherein a relative position and/or a relative velocity between the motor vehicle and the another vehicle are/is determined based on the sensor data, a time period up to the possible collision are/is determined based on the determined relative position and/or the relative velocity, and the severity of the possible collision is determined based on the time period.

7. The method according to claim 1, wherein a maximum deceleration of the another vehicle is determined based on the sensor data, and the severity of the possible collision is determined based on the determined deceleration.

8. The method according to claim 1, wherein the severity of the possible collision is determined based on the determined steering lock.

9. A control apparatus for a motor vehicle, the control apparatus comprising: a processor configured to: receive sensor data which describes an another vehicle from at least one sensor of the motor vehicle; determine a maximum steering lock of the another vehicle based on sensor data; determine a multiplicity of impact areas on the another vehicle and a probability of impact for each of the multiplicity of impact areas; determine a change in velocity which describes a difference between a velocity (V) of the motor vehicle before a collision and a collision velocity (V) of the motor vehicle after the collision based on the sensor data; determine a severity of a possible collision based on the determined change in velocity; release a brake of the motor vehicle if the determined severity exceeds a first threshold value; actuate a belt pretensioner if the determined severity exceeds a second threshold value; and pivot at least one part of a headrest of a vehicle if the determined severity exceeds a third threshold value, wherein the headrest is pivoted based on the probability of impact for each of the determined multiplicity of impact areas, and wherein the probability of impact for each of the determined multiplicity of impact areas is determined based on of the maximum steering lock and a probability distribution function, and wherein a mass of the another vehicle is estimated by the control apparatus based on the sensor data, and wherein the severity of the possible collision is additionally determined based on the estimated mass.

10. A driver assistance system for a motor vehicle comprising: at least one radar sensor; and a control apparatus configured to: receive sensor data which describes an another vehicle from the at least one sensor of the motor vehicle; determine a maximum steering lock of the another vehicle based on sensor data; determine a multiplicity of impact areas on the another vehicle and a probability of impact for each of the multiplicity of impact areas; determine a change in velocity which describes a difference between a velocity (V.sub.1) of the motor vehicle before a collision and a collision velocity (V.sub.c) of the motor vehicle after the collision based on the sensor data; determine a severity of a possible collision based on the determined change in velocity; release a brake of the motor vehicle if the determined severity exceeds a first threshold value; actuate a belt pretensioner if the determined severity exceeds a second threshold value; and pivot at least one part of a headrest of a vehicle if the determined severity exceeds a third threshold value, wherein the headrest is pivoted based on the probability of impact for each of the determined multiplicity of impact areas, and wherein the probability of impact for each of the determined multiplicity of impact areas is determined based on the maximum steering lock and a probability distribution function, and wherein a mass of the another vehicle is estimated by the control apparatus based on the sensor data, and wherein the severity of the possible collision is additionally determined based on the estimated mass.

11. The method according to claim 1, wherein the probability distribution function is a normal distribution function.

12. The method according to claim 1, wherein the motor vehicle is located in an interval of a deviation of +/−3σ based on the probability distribution function.

Description

(1) Embodiments and combinations of features which therefore do not have all the features of an originally formulated independent claim are therefore also to be considered as being disclosed.

(2) The invention will now be explained in more detail on the basis of preferred exemplary embodiments and with reference to the appended drawings, in which:

(3) FIG. 1 shows a schematic illustration of a motor vehicle according to an embodiment of the present invention, which motor vehicle has a driver assistance system;

(4) FIG. 2 shows a collision of the motor vehicle with another vehicle, wherein the collision is considered to be an inelastic impact;

(5) FIG. 3 shows a collision between the motor vehicle and the other vehicle, wherein the collision is considered to be an elastic impact; and

(6) FIG. 4 shows the motor vehicle behind which the other vehicle is located, wherein there is a risk of a collision between the motor vehicle and the other vehicle.

(7) In the figures, identical and functionally identical elements are provided with the same reference symbols.

(8) FIG. 1 shows a motor vehicle 1 according to an embodiment of the present invention. The motor vehicle 1 is embodied in the present case as a passenger motor vehicle. The motor vehicle 1 comprises a driver assistance system 2. The driver assistance system 2 comprises at least one sensor 3. In the present exemplary embodiment, the driver assistance system 2 comprises two sensors 3, which are each embodied as radar sensors. In this context, the sensors 3 are arranged in a rear area 4 of the motor vehicle 1. The sensors 3 can be installed, for example, concealed behind a bumper of the motor vehicle 1.

(9) The respective sensors 3 or the radar sensors can be used to emit a transmission signal in the form of electromagnetic radiation. This transmission signal can then be reflected by an object in a surrounding area 5 of the motor vehicle 1. On the basis of the transit time between the emission of the transmission signal and the reception of the reflected transmission signal a distance can then be determined between the motor vehicle 1 and the object. In addition, the sensors 3 can also be configured to determine a relative velocity between the motor vehicle 1 and the object on the basis of a Doppler shift between the emitted transmission signal and the transmission signal which is reflected by the object. The sensors 3 can then be used, in particular, to sense a further vehicle 7 as the object (see FIG. 2).

(10) In addition, the driver assistance system 2 comprises a control apparatus 6 which is formed, for example, by an electronic control unit of the motor vehicle 1. The control apparatus 6 is connected to the sensors 3 in order to transmit data. Corresponding data lines are not illustrated here for the sake of clarity. Therefore, sensor data which describes the object or the other vehicle 7 in the surrounding area 5 can be transmitted from the sensors 3 to the control apparatus 6. The control apparatus 6 can then determine the relative velocity between the motor vehicle 1 and the object on the basis of the sensor data. In addition, the control apparatus 6 can determine a current velocity V.sub.1 of the motor vehicle 1. For this purpose, for example corresponding data of a velocity sensor can be transmitted to the control apparatus 6.

(11) The severity of a possible collision between the motor vehicle 1 and the other vehicle 7 is then to be determined using the control apparatus 6 or the driver assistance system 2. In this context, in particular the case is considered in which the other vehicle 7 is located behind the motor vehicle 1 in the direction of travel of the motor vehicle 1. This is illustrated in FIG. 2. At a point in time T1 the other vehicle 7 is located behind the motor vehicle 1. The motor vehicle 1 is moving at the velocity V.sub.1 and has a mass m.sub.1. The other vehicle 7 is moving with a velocity V.sub.2 and has a mass m.sub.2. At a point in time T2 a collision occurs between the motor vehicle 1 and the other vehicle 7. In this context, the other vehicle 7 impacts against the rear area 4 of the motor vehicle 1. The collision is considered here to be an inelastic impact. After the collision, both the motor vehicle 1 and the other vehicle 7 have a velocity V.sub.i. In this case, the velocity V.sub.i corresponds to a collision velocity V.sub.c which describes the velocity of the motor vehicle 1 after the collision. This velocity V.sub.i can be determined according to the following formula:

(12) $V_i=\frac{m_1{V}_1+m_2{V}_2}{m_1+m_2}.$

(13) In comparison with this, FIG. 3 shows the case in which the collision is considered to be an elastic impact. It is assumed here that the entire impetus is transmitted from the other vehicle 7 to the motor vehicle 1 during the collision. In this context the other vehicle 7 remains stationary and the motor vehicle 1 moves at the velocity V.sub.e. Here, the velocity V.sub.e corresponds to the collision velocity V.sub.c of the motor vehicle 1. This velocity V.sub.e can be determined according to the following formula:

(14) $V_e=\frac{m_1{V}_1+m_2{V}_2}{m_1}.$

(15) Basically, the collision between the motor vehicle 1 and the other vehicle 7 cannot be considered to be an elastic impact nor an inelastic impact. The collision velocity V.sub.c of the motor vehicle 1 after the collision can be determined on the basis of a combination of an elastic impact and an inelastic impact. In this context, studies have shown that collisions at relatively high relative velocities can be considered to be essentially inelastic. At relatively low relative velocities the collision occurs according to an elastic impact. The collision velocity V.sub.c of the motor vehicle 1 after the collision can be determined according to the following formula:
V.sub.c=C.sub.ƒV.sub.i+(1−C.sub.ƒ)V.sub.e.

(16) In this context, C.sub.f describes a parameter which varies as a function of the relative velocity between the motor vehicle 1 and the other vehicle 7. The parameter C.sub.f can be stored, for example, in a memory unit of the control apparatus 6.

(17) In order to be able to determine the severity of the collision between the motor vehicle 1 and the other vehicle 7, a change in velocity is determined. This change in velocity describes the difference in velocity between the motor vehicle 1 before and after the collision. The change in velocity therefore describes the difference between the velocity V.sub.1 before the collision and the collision velocity V.sub.c. This is done on the basis of the sensor data of the sensors 3. The relative velocity between the motor vehicle 1 and the other vehicle 7 can be determined by means of the control apparatus 6 on the basis of the sensor data. The current velocity V.sub.1 of the motor vehicle 1 can be determined using a corresponding velocity sensor of the motor vehicle 1. The velocity V.sub.2 of the other vehicle 7 can then be determined from the difference between the relative velocity and the velocity V.sub.1 of the motor vehicle 1. The mass m.sub.1 of the motor vehicle 1 can be stored, for example, in the control apparatus 6.

(18) In addition, the mass m.sub.2 of the other vehicle 7 is estimated. For this purpose, the spatial dimensions of the other vehicle 7 can be determined on the basis of the sensor data. In particular, the length, the width and/or the height of the other vehicle 7 can be determined on the basis of the sensor data. For this purpose, for example chronologically successive measurement cycles can be carried out in which respective outer surfaces of the other vehicle 7 are detected or determined on the basis of the sensor data. Furthermore there can be provision that a classification of the other vehicle 7 is carried out on the basis of the sensor data. In this context, the other vehicle 7 can be assigned, for example, to the motorcycle class, motor vehicle class or lorry class.

(19) When the mass m.sub.2 of the other vehicle 7 is estimated, a confidence value can also be specified which describes how reliably the mass m2 has been determined. In this context, it is also possible to take into account, for example, whether it was possible to sense the other vehicle 7 completely or only partially using the sensors 3. For example it is possible to take into account the fact that parts of the other vehicle 7 are concealed by an obstacle. If the confidence value undershoots, for example, a predetermined threshold value, it can be assumed that the mass m.sub.2 of the other vehicle 7 cannot be determined reliably. In this case, a standard value is assumed for the mass m.sub.2 of the other vehicle 7.

(20) The collision velocity V.sub.c can be determined from the velocity V.sub.1 of the motor vehicle 1, the velocity V.sub.2 of the other vehicle 7, the mass m.sub.1 of the motor vehicle 1 and the mass m.sub.2 of the other vehicle 7 on the basis of the above described formula. In turn, the change in velocity can be determined from the collision velocity V.sub.c. The severity of the collision can then be estimated on the basis of the change in velocity.

(21) Furthermore, there can be provision that a probability of a collision between the motor vehicle 1 and the other vehicle 7 is determined. For this purpose, a relative position between the motor vehicle 1 and the other vehicle 7 can be determined by means of the control apparatus 6 on the basis of the sensor data. In addition, the relative velocity between the motor vehicle 1 and the other vehicle 7 or the velocity V.sub.1 of the motor vehicle 1 and the velocity V.sub.2 of the other vehicle 7 can be determined. Furthermore, the current acceleration of the other vehicle 7 can be determined on the basis of the sensor data. On the basis of this data, a chronological duration up to the collision can then be determined. In this context, there can also be provision that a maximum steering lock s.sub.i is determined in a first direction or to the left, and a maximum steering lock s.sub.r is determined in a second direction or to the right, for the other vehicle 7. In order to determine the maximum steering lock s.sub.i, s.sub.r it is possible to use the information from the classification of the other vehicle 7. In addition there is, in particular, provision that a maximum deceleration of the other vehicle 7 is determined. It is therefore possible to determine whether the other vehicle 7 can prevent the collision with the motor vehicle 1 through a corresponding steering movement and/or a braking operation. This is illustrated schematically in FIG. 4.

(22) In the rear area 4 of the motor vehicle 1, in addition impact areas A, B, C are also predefined. In this case, a probability of impact is to be determined for each of the impact areas A, B, C. Here, the arrow 8 describes possible points which the other vehicle 7 can intersect during its movement. The arrow 8 extends here along the rear area 4 of the motor vehicle 1, perpendicularly with respect to a longitudinal axis of the motor vehicle 1. A corresponding probability can be used to determine the probability of impact. The probability that the collision will be prevented by a steering movement of the other vehicle 7 can be described according to a normal distribution which extends between the maximum steering locks s.sub.i and s.sub.r. In this context, the motor vehicle 1 can be located, for example, in an interval with a deviation of +/−3 σ.

(23) In order to determine the probability of the collision being avoided, the probability distribution function between the point s.sub.1 and the point 1a can be integrated. In addition, the probability distribution function between the point 3b and the point s.sub.r can be integrated. The probability of the collision being avoided or not taking place is obtained from the sum of these two areas. In addition, the probability distribution function between point 1a and point 2a can be integrated in order to determine the probability of an impact for the impact area A. The probability of an impact for the impact area B can be determined by integrating the probability distribution function between the points 2a and 3a. The probability of an impact for the impact area C can be determined by integrating the probability distribution function between the areas 3a and 3b.

(24) Corresponding vehicle occupant protection apparatuses can be actuated using the driver assistance system 2. In this context, the vehicle occupant protection apparatuses can be actuated as a function of the determined change in velocity. If the change in velocity exceeds a first threshold value, the brake of the motor vehicle 1 can, for example, be released. In this case, a minor collision has occurred. If the change in velocity exceeds a second value, a belt pretensioner can be actuated. In this case, a medium-severity collision has occurred. If the change in velocity exceeds a third threshold value, at least one part of a headrest can be adapted, with the result that the latter supports the head of a vehicle occupant. In this context, a severe collision has occurred. In this context, there may be provision, for example, that the position of the at least one part of the headrest is determined as a function of the probabilities of impact for the impact areas A, B, C. In this case, a whiplash injury can be reliably avoided.

(25) The determination of the severity of the collision between the motor vehicle 1 and the other vehicle 7 is described here for the case in which the other vehicle 7 impacts against the rear area 4 of the motor vehicle 1. The principle here can be extended to other types of collisions between the motor vehicle 1 and the other vehicle 7. For example, the sensors 3 can be arranged in such a way that they can also monitor an area in front and/or an area to the side of the motor vehicle 1. Basically, the method can also be used to actuate other vehicle occupant protection apparatuses such as, for example, airbags.