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This paper describes the physical behavior of rollover situations from a sensor and an algorithm point of view. Algorithm solutions will be described with an emphasis on the rollover / no-rollover discrimination as well as the misuse scenarios. Integration of the Siemens advanced rollover sensing functionality as part of future airbag electronics will be discussed. The Siemens rollover algorithm technology and the performance will be demonstrated on some examples.

One important topic in future automotive safety systems will be a better protection of the occupants in rollover situations. Convenient systems are belt pretensioner and head airbags and, for convertibles, rollover bars. For an in-time detection of an imminent rollover and an activation of these safety systems by an electronic control unit there can be used different sensors, for example angular rate sensors, accelerometers, tilt switches. All kinds of these sensors were used in a vehicle test program in order to find out the best sensor architecture for this purpose. By use of a rotation table which is controlled according to the signals of the angular velocity sampled in these tests the rotation of the vehicle about the longitudinal axis can be simulated. This test equipment is used for the validation of trigger algorithms for the safety systems.

Some aspects on the detection of critical roll over situations for car safety applications will be presented. The detection via acceleration sensitive devices will be discussed as well as the detection via roll rate sensing elements. A combination of both sensors, the inclination sensing element and the roll rate sensing element seems to be the most feasible way for realization of a safe roll over detection.

The automotive industry has been very reluctant in using plastic housings for air bag triggering units. The critical question has always been: “Can the accelerometers, mounted inside the air bag triggering unit, discriminate the crash pulse satisfactorily? And can it also do so under all environmental circumstances and over the specified life span?” This paper describes the steps which were necessary to introduce plastic housings into the market for air bag triggering units.

Safety systems in the automotive area become more and more important. New sensors inside the passenger compartment evaluate additional information about the occupants. Forward-looking sensors identify the crash severity before the crash really happens. The variety and also the number of safety units per vehicle continues to rise. Some of these units get smarter than the current units. To control the actuators, a firing bus system is designed. The common part philosophy allows an easy adaptation of this system to different platforms. An image of the safety system is stored in the non volatile memory of the Central Control Unit (C2U). The External Remote Firing Circuits (ERIC) are connected at the desired locations along the bus line(s).