Activation control apparatus for passive vehicle occupant restraint and method of controlling activation of passive vehicle occupant restraint

Abstract

A floor sensor,measures a deceleration G applied to the length of a vehicle and outputs the deceleration as the measurement G. An arithmetic unit,carries out a predetermined arithmetic operation on the measurement G output from the floor sensor,, so as to determine a function f(G). A conditional activation unit,has a variation pattern of a threshold value T that varies with a variation in velocity v of a non-stationary object. The conditional activation unit,reads a threshold value T corresponding to an input velocity v from the variation pattern and compares the threshold value T with the value of the function f(G). In case that the value of the function f(G) exceeds the threshold value T, an activation signal A is input to a driving circuit,. A satellite sensor 30 outputs an ON signal when a deceleration of not less than a predetermined reference value is applied to the vehicle. A threshold variation pattern changing unit,changes the variation pattern of the threshold value T against the velocity v used in the conditional activation unit,to another variation pattern, in response to the ON signal output from the satellite sensor,. This structure of the present invention enables a passive vehicle occupant restraint to be activated at the earliest possible timing, irrespective of a type of a collision, in which the vehicle crashes.