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Airbag systems have become an essential safety device for guaranteeing the physical well-being of drivers and their passengers. Unlike other safety devices, airbags are used as the last resort in a collision, and because they are directly linked to the life of the driver and passengers, the proper functioning of the system is an issue of paramount importance. Hence, to ensure the precision and reliability of airbag operation, it is necessary to design a robust crash algorithm. Currently, several companies are working to achieve an optimal deployment time for airbags in collisions by diversifying the type and location of crash-related sensors. Nevertheless, several problems must still be confronted. For instance, when a vehicle operates off road or when the sensor inside the airbag control unit (ACU) receives a powerful shock, the vehicle's airbags may inadvertently deploy, although no collision has occurred, because a crashlike signal is delivered to the ACU. Alternately, in a collision situation that requires airbag deployment, the crash algorithm may make an erroneous judgment with regard to the collision configuration and miss the time frame for airbag deployment or fail to deploy the airbags altogether. Such problems can be attributed to the following two major causes: 1) Only signals produced through crash tests are used in the design of crash algorithms, and 2) the algorithms themselves only utilize postcrash input from the relevant sensors. To resolve these issues, this paper proposes a precrash algorithm that generates information about the crash scenarios before a collision has occurred. The purpose of the precrash algorithm is to make judgments about the impending collision configuration prior to impact by estimating the behavior of frontal objects and to communicate this information to the crash algorithm to enable correct recognition of the crash scenarios. This paper also proposes a crash algorithm based on crash-related sensors for the verification o- and interfacing with the proposed precrash algorithm. The limitations of existing crash algorithms, which deploy airbags using only postcrash signals, were resolved through the development of an integrative crash algorithm that combines the precrash and crash algorithms to reflect precrash information. The developed algorithm was verified by running a wide range of simulations using CarSim, based on data from real crash tests. The results showed that, compared with independently using the crash algorithm, adding precrash information estimation significantly improved the reliability of airbag deployment.
Date of Publication: May 2011