WO2005077720A1

WO2005077720A1 - System and method for the protection of a road user, particularly a pedestrian

Info

Publication number: WO2005077720A1
Application number: PCT/EP2004/053409
Authority: WO
Inventors: Frank Mack
Original assignee: Robert Bosch Gmbh
Priority date: 2004-02-09
Filing date: 2004-12-13
Publication date: 2005-08-25
Also published as: DE102004006196A1

Abstract

The invention relates to a protective system (1) for a road user, particularly a pedestrian. Said protective system (1) comprises vehicle-mounted protective means (5, 6) for road users, vehicle-mounted sensor means (2, 3) for detecting geometrical parameters of road users, and means (4) for calculating the point in time and location of an impact of the road user on the vehicle in case of a collision. Anticipating sensors (2, 3) which cause an engine hood (8.1) to be raised and/or an exterior airbag to be deployed can be used, for example.

Description

SYSTEM AND METHOD FOR PROTECTING A TRAFFIC PARTICIPANT, IN PARTICULAR PEDESTRIAN

State of the art

The invention relates to a protection system for road users according to the preamble of claim 1. Protection systems for vehicle occupants, in particular

Belt tensioners and airbags are standard today and are offered for practically all vehicle classes. They offer optimal protection for vehicle occupants and have made a significant contribution to reducing the number of accident victims. So far, relatively little has been achieved to improve protection for the weakest road users, pedestrians. Legislative activities have therefore already been envisaged which aim to improve the protection options for pedestrians through statutory provisions. In addition, vehicle manufacturers have made a voluntary commitment to improve pedestrian protection through better vehicle construction. An improvement is to be achieved, for example, by sensors and actuators adapted to pedestrians. In the area of the sensors, primarily contact sensors are provided, which are arranged in the bumper. These contact sensors, which preferably extend over the entire width of the bumper, are based on a force measurement or a deformation. Examples of such force sensors are

Piezo foils, strain gauges, light sensors or sensors made of a composite material. Deformation sensors also use light guides or simple contact switches. Furthermore, there is the option of attaching various sensors that measure acceleration or forces directly to the so-called crash box.

In addition, predictive sensors, so-called pre-crash sensors, are also planned, e.g. Video or radar sensors, which should recognize a pedestrian via an image evaluation or based on the reflected signals.

Airbag systems can essentially be integrated as protective means for the pedestrian in the frame of the windshield or in the engine compartment of the vehicle. Or the bonnet of the vehicle can be raised to alleviate the impact of a pedestrian. A disadvantage of the previously proposed concepts is that no prediction can be made about the point of impact and the point of impact of particularly vulnerable parts of the body of the pedestrian, in particular the head, on the hood or the windshield of the vehicle.

Advantages of the invention

A protection system with the features of claim 1 makes it possible, in particular, to improve the triggering of the protective means for the pedestrian by predicting the time and / or the location of the head impact. If the approximate impact time and the possible impact location were known with sufficient accuracy, existing protective agents can be used much more effectively. In particular, the protective effect on pedestrians of different sizes can also be better adapted, since existing protective means are used in different ways for adults and children become. Since most of the serious injuries to pedestrians are head injuries, optimized triggering of the protective equipment can prevent serious injuries in many cases. The invention is therefore based on the knowledge that, in addition to other parameters, the size of a pedestrian is of particular importance for the use of the protective means. The size of a pedestrian at risk is therefore detected by means of a forward-looking sensor system. The impact time and location are then determined from this recorded size value. With the help of the values determined in this way for the time of impact and the location of the impact, the protective means for the endangered pedestrian are optimally controlled.

drawing

The invention is explained in more detail below with reference to the drawing. It shows

Figure 1 is a block diagram of a protection system

Figure 2 shows a vehicle and a pedestrian with an explanation of important geometric sizes

FIG. 3 shows a simplified model for the prediction of the impact time of the head of a road user

Figure 4 is a simplified model for predicting the impact on the windshield

Figure 5 is a flow chart Description of the embodiments

Figure 1 shows a block diagram of a protection system 1. Das

Protection system comprises a control unit 4. Sensor means 2, 3 are connected to the control unit 4 on the input side. Predictive sensors and impact sensors can be provided as sensor means 2, 3. On the output side, protection means 5, 6 for road users are connected to the control unit 4. The sensor means 2, 3 record geometric parameters of road users, as well as contacts between the vehicle and a road user. The control unit 4 evaluates the signals from the sensor means 2, 3 and, depending on this evaluation, controls the protection means 5, 6 for the road users in the event of a collision risk.

FIG. 2 shows, in a schematic representation, a vehicle 8 and a road user, namely a pedestrian 7, in a typical collision situation. In addition to the sensor means 2, 3 'not shown here, the vehicle 8 includes a bonnet 8.1, a windshield 8.2, a bumper 9, and protective means 5, 6 for road users, which are also shown here only schematically as an unfolded airbag. As can be understood from the later explanations, the bonnet 8.1 of the vehicle 8 can also be used as a protective means. The pedestrian 7 is characterized by geometric parameters, such as his height or height h and the diameter d of his head 7.1. The head 7.1 is regarded as a particularly sensitive part of the body of the pedestrian 7, which is to be particularly protected by the protection system. LE is the contact point between pedestrian 7 and vehicle 8 in the event of a collision. The point LE has a distance LEH from the road surface and is at the same time the pivot point about which the pedestrian 7 turns after the collision.

Figure 3 shows a sketch of a simplified model for predicting the impact of the head 7.1 of a

Road user. In this model presentation, it is assumed that a collision between a vehicle 8 (FIG. 2) and a road user, in particular a pedestrian 7 (FIG. 2), has taken place. Only the bonnet 8.1 of the vehicle is shown, which is set at an angle α with respect to a horizontal plane E and has a length LMH. The first contact in the collision between the vehicle 8 and the pedestrian 7 took place at the point LE in the front area of the vehicle 8. This point LE is also the fulcrum around which the body of the pedestrian 7 rotates due to an accident. The center M of the head 7.1 of the pedestrian 7 is at a distance L = h-LEH -d / 2 from the pivot point LE. At the time of the collision, the still standing pedestrian 7 and the bonnet 8.1 of the vehicle 8 enclose an angle α. With respect to the vehicle 8, the pedestrian 7 has a relative speed v. After the collision, the head 7.1 of the pedestrian 7 moves towards the bonnet 8.1 at the angular velocity α.

If, as shown in FIG. 4, the distance L is greater than the length LMH of the bonnet 8.1, the head 7.1 of the pedestrian 7 will hit the windshield 8.2 of the vehicle 8 and will not hit the bonnet 8.1 of the vehicle 8. The probable impact location of the head 7.1 on the windshield 8.2 is at a distance L from the fulcrum LE.

The mode of operation of the protection system and the method for the protection of road users will now be described in the following with the aid of the discharge diagram shown schematically in FIG described. The process can be divided into four steps 51 to 54.

In a first step 51, geometric parameters, such as in particular the body size of the pedestrian 7, are determined by means of a forward-looking sensor system 5, 6. The body size of the pedestrian 7 is recorded particularly advantageously by means of a stereo camera. However, other predictive sensors such as laser scanners, lidar, radar, ultrasound or infrared sensors can also be used to determine the height of the pedestrian 7. In addition, the relative speed v of the pedestrian 7 in relation to the vehicle 8 is determined with the aid of the forward-looking sensor system 5, 6. If this determination of the relative speed v of the pedestrian 7 with the sensor 5, 6 used is only relatively imprecise, the speed of the vehicle 8 can also be used as an alternative, since pedestrians generally move much more slowly than about 20 km / h and Accidents with a driving speed of well over 20 km / h lead to serious injuries to pedestrians.

In a second step 52, it is now observed whether there is a collision between the pedestrian 7 and the vehicle 8, for example whether a strong impact of the pedestrian 7 on the front of the vehicle 8 occurs, for example. This can be recognized with the aid of the forward-looking sensor and / or with the contact sensors arranged in the vehicle 8. With some contact sensors, the relative speed can also advantageously be determined from the signal curve.

In a third method step 53, the measured height of the pedestrian 7, the

Relative speed v between the pedestrian 7 and the vehicle 8 and other known vehicle characteristics, the time and the location of the impending impact. It is thus determined, for example, when and at which point in vehicle 8 an impact of head 7.1 of pedestrian 7 on vehicle 8 is to be expected. This is explained using a simple model with reference to FIG. 4.

In this model (FIG. 4) it is assumed that the pedestrian 7 bumps with his legs or his hip at the uppermost point LE of the front front (LE: Leading edge) of the vehicle 8, and that the upper part of the body of the pedestrian 7, in particular also his head 7.1, performs a rotary movement around this point LE. The point LE is located at LEH (Leading edge height) above the surface of the street. The distance L (FIG. 3) is the distance between the point LE and the center of the head 7.1 of the pedestrian 7. If this distance L is shorter than the length LMH of the bonnet 8.1 of the vehicle 8, the head 7.1 is based on the model the bonnet 8.2 and not hit the windshield 8.1 of the vehicle 8. At the location on the bonnet 8.2, which is this distance from LE, with the same y-coordinate (DIN 70000) as the point of impact on the bumper. If one can determine the location of the collision in the y-direction with the help of the predictive and / or the contact sensors, then the location on the hood 8.2 and / or the windshield 8.1 can also be determined in the y-direction.

The head 7.1 of the pedestrian 7 strikes the bonnet 8.2 of the vehicle 8 after overcoming the angle α. The angle is the angle between the bonnet 8.2 and the vertical and is thus α = 90 ° -ß, where ß is the angle of attack of the bonnet 8.2. If one now knows the relative speed v of the pedestrian 7 in relation to the vehicle 8 and the length of the distance L between the point LE and the head 7.1 of the pedestrian 7, the angular speed and, with this, the impact time t2 can be calculated from the following relationships: (1) α = 90ß- = ωt

(2) ω = vlL

(3) L = h L-Ε H-dl2

(4) L = B, 9 & -E H

And thus the following applies for the point of impact t2:

(5) t2 = φc OL, S £ 5 $ / v

It was assumed that the diameter d of the head 7.1 of the pedestrian 7 corresponds to a value of approximately 10% of the body size of the pedestrian 7. If the forward-looking sensor can also be used to determine the head diameter d of the pedestrian 7, the following relationship can alternatively be used to calculate the time of impact:

(6) tl JM L lE lH ^ d I 2

The height LEH of the point LE and the angle of attack β of the bonnet 8.2 are characteristic data of the vehicle 8 and are therefore known. The

Relative speed v of the pedestrian 7 in relation to the vehicle

8 can be determined using the forward-looking sensor system.

In the following, this model presentation is based on a concrete

Numerical example verified. With the values h = 1.80m, LEH = 0.8m, d = 0.2m, ß = 15 °, v = 40km / h = 11, 1 m / s, = 75 °, the following results from the relationships:

(7) ω = 1.31t (8) t2 Φ, 3 b <t, 8 0m8-0, l> / 4 1, lsf, l 0ώi 0 6 s

This value, like other numerical examples, is in good agreement with values from the literature that were achieved experimentally with dummies or with complicated multi-body simulations.

If the distance L is greater than the length LM of the bonnet 8.2, the head 7.1 will hit the windshield 8.1 and not the bonnet 8.2. At the point on the windshield 8.1, which is just the length L from the point LEH, with the same y-coordinate (DIN 70000) as the point of impact on the bumper 9. To calculate the point of impact, simply use the angle instead of the angle be used between the point of impact on the windshield 8.1 and the point LE (see FIG. 4). The time of impact can easily be calculated using the angle α. This results in:

(9) t2 = 0- - <E 5J lv / v.

With knowledge of the angle α of the windshield, the angle α can be calculated using simple geometric relationships.

To do this, the known values must be in the equation

_^ ~ Lc Iύf -M cHo sα

(7) tanδ = - Ls Bf -ύi sü nα

used and these are then resolved to α.

As an alternative to the model described, other, even more complicated, models can be used. However, in the In practice, only comparatively simple models can be used in real time for a triggering decision of protective means 5, 6. The representation of body size and relative speed on the impact time and location of the head 7.1 can also be done with the help of a look-up table, which contains, for example, experimental (with dummies) or values determined by simulation.

Protection means 5, 6 are then used in a fourth step 54. If one has now estimated the point of impact and the point of impact of the head 7.1 on the bonnet 8.1 or the windshield 8.2, the protective means 5, 6 can now be optimally adapted to this situation. For example, In the event of an impending impact on the windshield 8.2 of the vehicle 8, airbags can be triggered as a protective means at the right time in order to protect the head 7.1 of the pedestrian 7. Furthermore, in the event of an impending impact on the bonnet 8.1 of the vehicle 8, the bonnet 8.1 can be raised at the right place at the right time in order to offer the pedestrian 7 the best protection. It may be advantageous if the bonnet 8.1 still has a residual speed when it comes into contact with the impacting head 7.1 of the pedestrian 7, so that its restraining effect on the pedestrian 7 is greater. If there is only a comparatively short time until the head 7.1 hits, which is the case, for example, with a child, a quick lifting of the bonnet 8.1 with a short lifting path can be preferred to a longer lifting with a longer lifting path. In this way, the time course and the maximum lifting distance of the bonnet 8.1 can be optimally selected.

As an alternative to the described method, there is also

Possibility in the first method step 51 to estimate how long it would take for the head 7.1 to hit the bonnet 8.1 or the windshield 8.2 if the pedestrian 7 were hit by the bumper 9 of the vehicle 8. This information can then be used to carry out the second method step 52 to optimize, because you know how much time is available for a trigger decision. A bonnet 8.1, which takes approximately 50 ms to be completely set up in its protective position, is assumed as a concrete example. If one knows from the estimation of the point in time of the impact that it takes about 60 ms for the head 7.1 of the pedestrian 7 to impact, then a triggering decision must be made within 10 ms based on the information from the contact with the bumper 9. However, if you have calculated that the head 7.1 only hits the bonnet 8.1 after about 90 ms, then a decision has to be made after about 40 ms. Since a longer period of time is available for the acquisition of information, a more reliable triggering decision can be made if necessary.

In the embodiment described above, a

Collision between a vehicle and a pedestrian, assumed to be one of the weakest and most vulnerable road users. The use of the inventive solution is also conceivable in collisions in which vehicles and drivers of two-wheeled vehicles, such as, for example, cyclists and / or motorcyclists, are involved.

Claims

Expectations

1. Protection system (1) for road users comprising vehicle-related protection means (5, 6) for road users, vehicle-based sensor means (2, 3) for recording geometric parameters of road users, and means (4) for calculating the impact time and location of the road user the vehicle in the event of a collision.

2. Protection system according to claim 1, characterized in that the sensor means (2,3) comprise impact sensors.

3. Protection system according to one of the preceding claims, characterized in that the sensor means (2, 3) comprise forward-looking sensors.

4. Protection system according to one of the preceding claims, characterized in that the protective means (5, 6) comprise outwardly effective airbags (so-called external airbags).

5. Protection system according to one of the preceding claims, characterized in that the protective means (5, 6) comprise a hood (8.1) of the vehicle (8) which can be changed in terms of its position.

6. A method for the protection of road users with vehicle-bound protective means, characterized in that that geometric parameters of the road user (7) are recorded, that it is checked whether there is a collision risk, that if a risk of a collision is determined, the potential collision point between the vehicle (8) and the road user (7) is determined from the geometric parameters of the road user (7) and operating parameters of the vehicle (8) impact point and impact time of particularly sensitive body parts (head 7.1) of the road user (7) are determined, and that, depending on the impact point and the impact time, vehicle-bound protective means (5,6) for protection of the road user (7) are activated.

7. The method according to claim 6, characterized in that in the event of an impending impact of a sensitive body part (head 7.1) of a road user (7) on the windshield (8.2) of the vehicle (8) at least one airbag reducing the impact is deployed.

8. The method according to one of the preceding claims, characterized in that in the event of an impending impact of a sensitive body part (head 7.1) of a road user (7) on the hood (8.1) of the vehicle (8), the position of the hood (8.1) is changed ,

9. The method according to any one of the preceding claims, characterized in that the angle of attack of the hood (8.1) is changed.

10.The method according to any one of the preceding claims, characterized in that the hood (8.1) is accelerated in the direction of the impacting road user (7).

1.A method according to one of the preceding claims, characterized in that the activation of protective agents is controlled as a function of the determined impact time.