Seat belt tension determination using multiple belt tension sensors

摘要

A vehicle seat belt is provided with multiple seat belt tension sensors providing output signals that are received and averaged. Signals having values outside a band around the average are dynamically tested against a signal from an occupant weight sensor, vertical seat accelerometer or other sensor indicating expected vertical acceleration of an occupant restrained by the seat belt. This test provides variance values and time-averaged values of each signal, derives a reference value for each signal and compares the variance value for each signal to its reference value. If the comparisons indicate that the dynamic variance of the signals is significantly different, the signal is declared invalid and the average value is recalculated without the invalid signal. The final average signal after removal of all invalid signals determines the belt tension value, which may be used to compensate a weight sensor signal in an occupant characterization system to help control deployment of a vehicle airbag.