The invention relates to a method of detecting the seriousness of a vehicle crash, in which the output signal of an acceleration sensor is processed and supplied to a neural network which controls a triggering unit for an occupant protection system.
Such a method is known from U.S. Pat. No. 5,583,771 A. In this case, the output signal of a single acceleration sensor is stored for a defined time period with respect to its path, and information, such as the amplitude, the course of the velocity, etc., is determined from the signal path. This information is fed as input information into the neural network which decides whether a single air bag is ignited.
The known method has a large number of disadvantages. On the one hand, it is necessary to store the path of the crash signal for a predefined time period and, naturally, only analyze it subsequently. The use of a single acceleration sensor does not permit judgment of all possible vehicle crashes with respect to their seriousness with sufficient certainty.
The cause is a normally existing directional dependence of acceleration sensors. If the acceleration sensor is capable, for example, of detecting a frontal crash, a side crash can, as a rule, not be detected or can at least not be detected with the same precision. Such a single acceleration sensor is, as a rule, arranged centrally in the vehicle. As a result of the vehicle structure, the deceleration at the site of the acceleration sensor takes place only in a delayed manner and its path is completely different from the path taking place, for example, at the impact site of an obstacle. As a rule, this results in considerable problems with respect to detecting the seriousness of the vehicle crash with sufficient precision. This sometimes results in the problem of not being able to detect the crash in sufficient time.
Since the neural network is naturally trained by means of preceding signal paths for different types of crashes, experience has shown that when looking at only a single sensor signal, no conclusion can be drawn on the further course of the vehicle crash if, as in U.S. Pat. No. 5,583,771, only the previous path of the sensor signal is analyzed. The known method is therefore only suitable to a limited extent. It supplies only rough outlines and furnishes useful criteria only for the decision on whether an occupant protection system should be triggered at all.
It is an object of the present invention to provide a method of the above-mentioned type which supplies significantly better information concerning a vehicle crash.
The invention meets these needs by providing a method of detecting the seriousness of a vehicle crash, in which the output signal of an acceleration sensor is processed and supplied to a neural network which controls a triggering unit for an occupant protection system. For detecting also the course of the vehicle crash, additional crash sensors are provided, which supply a physical value identical with or similar to the output signal of the acceleration sensor as input signals for the neural network. By means of the triggering unit, several occupant protection systems are controlled corresponding to the seriousness and the course of the vehicle crash.