Patent ID: 7797091

Claim:
A rollover judgment apparatus for judging whether or not a vehicle will roll over by comparing an output of a roll angular velocity sensor with a threshold, said device comprising: a threshold change functional unit for judging whether or not to change the determination threshold on a basis of a roll angular velocity, a tilt angle of the vehicle which is acquired by integrating the roll angular velocity, and at least one of: a lateral direction acceleration obtained from a lateral direction acceleration sensor, and a steering wheel angle obtained from a steering wheel angle sensor, and changing the determination threshold in response to the judgment being made by the threshold change functional unit to change the determination threshold; a rollover judging unit for judging whether or not the vehicle will roll over on a basis of the determination threshold, and said tilt angle of the vehicle; a safing functional unit for detecting a tip-up of the vehicle in relation to a motion of the vehicle; and a curtain air bag deploying unit for controlling expansion of a curtain air bag on a basis of an output of said rollover judging unit and an output of said safing functional unit, wherein the rollover judging unit judges whether or not the vehicle will rollover by comparing the tilt angle to the unchanged determination threshold when the judgment is made by the threshold change functional unit not to change the determination threshold, and by comparing the tilt angle to the changed determination threshold when the judgment is made by the threshold change functional unit to change the determination threshold.