| 摘要 |
A CPU 30 first receives data of accelerations Gx and Gy applied respectively along a longitudinal axis and a lateral axis of a vehicle (S20). The CPU 30 then calculates an arithmetic value fx from the acceleration Gx in the longitudinal direction according to specified arithmetic operations, and calculates an arithmetic value fy from the acceleration Gy in the lateral direction according to specified arithmetic operations (S22). The CPU 30 subsequently projects vectors based on the arithmetic values fx and fy in a preset direction a to yield projective components of the vectors, and determines a sum fa of the projective components (S24). The CPU 30 compares the projective component fa with a threshold value fth(a) previously set for the direction a, and determines whether or not the projective component fa is greater than the threshold value fth(a) (S26). When determining that the projective component fa is greater than the threshold value fth(a), the CPU 30 generates an activation signal to activate air bag units 60 to 66 (S28). The structure of the present invention does not require the calculation of the magnitude or the direction of a composite vector, thereby being free from complicated and time-consuming arithmetic operations. No division is included in the required arithmetic operations, so that the result of calculation does not diverge. <IMAGE> |
