DE102011107519B4 - Method for evaluating an impact by means of impact sensors on a vehicle - Google Patents

Abstract

Method for assessing an impact by means of impact sensors (SL, SM, SR) on a vehicle,
wherein for an assessment of an impact as a triggering or non-triggering event at a certain impact position (Z7)
the signal of the impact sensor (SM) closest to this position (Z7)
and at least one spatially adjacent, but further spaced impact sensor (SR, SL) is taken into account and
these signals are provided with weights and the impact is evaluated, characterized in that
for at least one evaluation variable, the signal of the impact sensor (SM) closest to this position (Z7) is provided with a lower weight than the signal of the at least one further-spaced sensor (SR, SL).

Description

The invention relates to a method for evaluating an impact by means of impact sensors on a vehicle according to the preamble of claim 1.

In particular, acceleration sensors, but increasingly also pressure sensors, capacitive sensors or comparable systems are used as impact sensors on or in vehicles, which are each sensitive to the force impact upon impact and generate a corresponding signal. The signals of these impact sensors are compared with predetermined magnitudes and / or with each other, and the impact is evaluated, i. E. in particular, for example, determines the nature and / or strength of the impact to appropriately adjusted subsequently suitable security measures, such as the deceleration of the vehicle, triggering of occupant or even pedestrian protection devices to activate.

Such as the DE 10 2004 031 557 A1 can be seen, the sensors are preferably spatially adjacent, for example, distributed over the front of the vehicle, vehicle side or rear of the vehicle arranged. The sensors detect not only an impact directly on this sensor itself, but also the forwarded via the bumper, sheet metal parts and vehicle body forces, the strength of the signal naturally decreases with the distance to the point of impact. Precisely when designing the algorithm, elaborate calibrations and often also a deviating algorithm for evaluating such impact events must be provided for impact points away from the sensors. Optimally, one would therefore have to provide as many such sensors on the vehicle, which would, however, lead to considerable costs.

Thus, for an activation of pedestrian protection devices, a collision of a pedestrian is to be distinguished from a so-called non-triggering event, that is to say an impact of a ball, hammer blow or the like.

However, the strength and the temporal course of the signals of the impact sensors is highly dynamic for these different events and can not be readily distinguished, especially in early periods. For the activation of the pedestrian protection but even earlier triggering than for occupant protection is required and therefore the previous method at least partially unsuitable.

The object of the present invention is therefore to present an improved method for assessing an impact, which allows a particularly good assessment of the impact without significant additional costs.

This object is solved by the features of the independent claims. Advantageous developments of the invention will become apparent from the dependent claims, wherein combinations and developments of individual features are conceivable with each other.

An essential idea of the invention is that, for at least one evaluation variable, the signal of the impact sensor closest to this position is provided with a lower weight than the signal of the at least one further-spaced sensor. This may seem absurd at first because, of course, in a crash at a certain position, the signal from the nearest impact sensor to that position is highest. However, it has been recognized that it is not this strongest signal that is most meaningful, especially for certain case discriminations with lower collision energy, ie non-triggering events and pedestrian impacts, since this signal has barely distinguishable high initial amplitudes for all events. While irreversible plastic deformation of the collision objects already plays a major role in events with high collision energy, the signals of the impact sensors are strongly influenced by elastic vibrations in events with lower collision energy.

Although spatially adjacent, but just a little further spaced sensors, however, even measure these smaller events even, but filtered and dampened by the vehicle structure. It can be seen that this filtering and attenuation depends in a particular way on the mass of the collision object and just for a distinction of these impact events with lower energy, the spaced sensors are better suited than the impact sensor immediately met.

The invention now teaches to consider this on the basis of the weights and, for at least one evaluation variable, the signal of the impact sensor closest to this position with a lower weight to provide as the signal of the at least one more widely spaced sensor. This is preferably true in particular for distinguishing a pedestrian impact from a non-triggering case.

The signal of the impact sensor closest to this position can even be given a weight equal to zero, that is to say completely ignored, whereby the mere disregard of the signal of this impact sensor in the algorithm is to be understood as the use of the weight "zero".

Alternatively, even the signal of the impact sensor closest to this position can be provided with a weight less than zero, ie even as a damping component with respect to the signals of the more widely spaced, adjacent sensors.

• 1: Skizzierung eines Systems mit drei Aufprallsensoren
• 2: Signalverlauf des Geschwindigkeitsabbaus am getroffenen zentralen Sensor bei einem Nicht-Auslösefall sowie einem schwachen Auslösefall (Kleinkind)
• 3: Signalverlauf des Geschwindigkeitsabbaus an den beiden nicht getroffenen, benachbarten Sensoren wiederum beim gleichen Nicht-Auslösefall sowie dem schwachen Auslösefall (Kleinkind) gemäß 2

The invention will now be explained in more detail by means of exemplary embodiments with the aid of the figures. Hereinafter, for functionally identical and / or identical elements may be denoted by the same reference numerals. Show it

• 1 : Sketching a system with three impact sensors
• 2 : Signal curve of the speed reduction at the struck central sensor in a non-triggering case and a weak triggering case (infant)
• 3 : Signal curve of the speed reduction at the two unaffected, adjacent sensors again at the same non-triggering case and the weak triggering case (toddler) according to 2

1 shows a vehicle front with three spatially distributed therein arranged impact sensors SL . SM and SR , The sensors are designed, for example, as acceleration sensors and integrated into the front structure of the vehicle. The vehicle front is now in 11 virtual zones for the algorithm Z1 to Z11 divided, whereby again different areas 1 to 4 result, for which different adjustments of the algorithm are required.

While the areas 1 and 3 each detected very well by one of the sensors, resulting in particular in the field 4 However, due to the distance to the two adjacent sensors, there is still a need for considerable adaptation and calibration is not always possible. The border area 2 is inevitably covered only by the nearest impact sensor.

But also the supposedly best covered areas 1 and 3 , So in a central hit of a sensor, have in the distinction just in the border between stronger non-triggering case, so for example a basketball or small animal and a weak trigger case, so for example. A toddler significant problems in the calibration.

So shows 2 The very similar courses of the speed reduction, that is the integrated acceleration, are good enough for the centrally hit sensor selected here by way of example SM in a non-triggering case xSM (0) and a weak trigger case xSM (1) , Although the difference in the further course of time is clearer, but these are already the Rückschwingvorgänge in the opposite direction of the impact and for a triggering decision on the one hand too late and on the other hand also only partially suitable.

The 3 on the other hand shows the progressions of the speed reduction at the right and left sensor. Of course, the strength of the signals is significantly lower than that of the centrally hit sensor SM and delayed, but still provide better distinguishability between a non-triggering case xSL (0) / XSR (0) and a weak trigger case xSL (1) / XSR (1) ,

The signal xSM of this position Z6 nearest impact sensor SM Thus, with a lower weight than the signal xSL, xSR the more distant sensors SL . SR Mistake. Expressed as a formula, for example: $$\text{X}\left(\text{Z}6\right)=\text{G}1-\text{xSM}+\text{G2 * XSR}+\text{G3 * xSL}.\text{where G1 <G2}\text{, G3}$$

und $$\text{X}\left(\text{Z7}\right)=\text{G}1*\text{xSM}+\text{G2*xSR},\text{ wobei G1<G2}\text{.}$$

For the position Z6 becomes the signal xSM in one embodiment even provided with the weight zero, ie the triggering decision for pedestrian protection devices based solely on the adjacent sensors SL and SR met while for the zones Z5 and Z7 the signal xSM with a lower weight than the signal xSL respectively. XSR , $$\text{X}\left(\text{Z}6\right)=0*\text{xSM}+\text{G1 * XSR}+\text{G2 * xSL}.\text{where G1 and <figure-callout id="2" label="G" filenames="DE102011107519B4\_0004.png" state="{{state}}">G</figure-callout>}2>\text{Are zero}$$

and $$\text{X}\left(\text{Z7}\right)=\text{<figure-callout id="1" label="G" filenames="DE102011107519B4\_0005.png,DE102011107519B4\_0006.png" state="{{state}}">G</figure-callout>}1*\text{xSM}+\text{G2 * XSR}.\text{where G1 <G2}\text{,}$$

Of course, the method can also be applied to the other zones, ie for the zone Z2 instead of the signal xSL the triggering decision for pedestrian protection devices based solely on the adjacent sensor SM and just not the just taken sensor SL to be hit. So it is not always necessary to have two adjacent sensors next to the sensor at this position, but one more is sufficient.

The use of these to the actual signal strength yes rather inverse weights also does not necessarily apply to all conceivable evaluation parameters of an impact, but only for at least one, in particular for distinguishing a pedestrian impact of a (low energy) non-triggering case, while for the distinction of an impact with a serious non-triggering case (eg small animal) at another position or for deriving a second evaluation size, the signal of the direct hit sensor, for example, can certainly be used.

The signal of the impact sensor closest to a position may also be provided with a weight less than zero in certain vehicle configurations and evaluation parameters, i. For example, X (Z6) = G0 * xSM + G1 * xSR + G2 * xSL, where G1 and G2 are> zero and G0 are less than zero.

These weights are preferably determined vehicle-specifically within the framework of the algorithm calibration, for example, adapted and stored in the control unit in a memory unit. The supply of the control units to vehicle manufacturers and workshops can be done first with the basic algorithm and the weights for parameterization at the assembly line end or the workshop are recorded. The control unit as a tradable unit therefore has a corresponding memory unit and an interface for connecting impact sensors and a computing unit for carrying out the method.

Claims (6)

Method for assessing an impact by means of impact sensors (SL, SM, SR) on a vehicle, the signal of the impact sensor closest to this position (Z7) being the trigger signal for a crash or non-triggering event at a specific impact position (Z7) (SM) as well as at least one spatially adjacent, but further spaced impact sensor (SR, SL) is taken into account and these signals are provided with weights and the impact is evaluated, characterized in that for at least one evaluation variable, the signal to the position ( Z7) nearest impact sensor (SM) is provided with a lower weight than the signal of the at least one more widely spaced sensor (SR, SL). Method according to Claim 1 , characterized in that the signal of the next to this position (Z7) impact sensor (SM) is provided with a weight equal to zero. Method according to Claim 1 , characterized in that the signal of the next to this position (Z7) impact sensor (SM) is provided with a weight less than zero. Method according to one of the preceding claims, characterized in that it serves to distinguish a pedestrian impact from a non-triggering case. Method according to Claim 1 , characterized in that it is used to derive a first evaluation variable, while the signal of the nearest to this position impact sensor is used with a different weight for deriving a second evaluation variable. Control unit for a motor vehicle having at least one interface for connecting impact sensors (SL, SM, SR), a memory unit for storing at least one basic algorithm for execution the method according to any one of the preceding claims and a computing unit for performing the method.

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