LATERAL AND LONGITUDINAL VELOCITY DETERMINATION FOR AN AUTOMOTIVE VEHICLE

A system ( 18 ) for controlling a safety system ( 44 ) of an automotive vehicle ( 10 ) includes a longitudinal acceleration sensor ( 36 ), a vehicle speed sensor ( 20 ), a lateral acceleration sensor ( 32 ), a yaw rate sensor, and a controller ( 26 ). The controller ( 26 ) determines a stability index and provides a first observer that determines a reference longitudinal velocity in response to the longitudinal acceleration signal, the yaw rate signal, a pitch attitude and vehicle speed from wheel speed sensors. The controller ( 26 ) determines a reference lateral velocity in response to the lateral acceleration signal, the yaw rate signal, a roll attitude, a pitch attitude and vehicle speed from the wheel speed sensors. The controller provides a second observer that determines a second longitudinal velocity in response to the longitudinal acceleration signal, the yaw rate signal, a lateral velocity, the pitch attitude and a first adjustment based on the longitudinal reference velocity. The controller determines a second lateral velocity in response to the lateral acceleration signal, the yaw rate signal, a roll attitude, a pitch attitude and a second adjustment based on the lateral reference velocity. The controller determines an output lateral velocity and an output longitudinal velocity in response to the first observer, second observer and the stability index. The controller controls the safety system in response to the output lateral velocity and the output longitudinal velocity.