Method and apparatus for controlling an actuatable restraint device using a velocity/displacement based safing function with immunity box

摘要

An apparatus and method for controlling an actuatable occupant restraint device having a plurality of actuatable stages (24, 26), the apparatus including a crash sensor (14, 16) for sensing crash acceleration and providing a crash acceleration signal indicative thereof. A controller (22) determines a velocity value (74) and a displacement value (80) from the crash acceleration signal. A safing function controls enabling and disabling of a deployment control circuit in response to the determined velocity (74) and displacement (80) values. A displacement based velocity threshold (133) and a displacement threshold value (125) define an immunity box. The velocity threshold value (133) varies as a step function of displacement. If the velocity/displacement values are within the immunity box, the safing function is in a disabling condition. If either value is outside of the immunity box, the safing function is in an enabling condition. A side impact sensor (28) and side impact crash event circuit (122) determine if a side impact crash event is occurring. If a side impact crash event is occurring, the threshold values (125, 133) of the immunity box are adjusted.