Control method for occupant restraint apparatus and occupant restraint apparatus

1. A method for controlling an occupant restraint apparatus, the method comprising:

detecting an obstacle in a travelling direction of a vehicle that may potentially collide with the vehicle;

predicting a type of collision between the obstacle detected and the vehicle;

setting conditions for expanding an airbag of the vehicle based on the collision type predicted; and

controlling both of the expansion of the airbag and gas discharge from the airbag according to the conditions set by attaching one end of a flap to the airbag and based on the conditions set either:

holding the other end of the flap as the airbag is expanding to restrict the expansion size of the airbag and to overlap a large vent of the flap with an opening in the airbag to increase flow of gas out therefrom, or releasing the other end of the flap as the airbag is expanding to increase the expansion size of the airbag and to overlap a small vent of the flap with the airbag opening to decrease flow of gas out therefrom.

2. The method of claim 1 , wherein detecting the obstacle comprises detecting the position and relative speed of the obstacle with respect to the vehicle based on images of views in the travelling direction of the vehicle.

3. The method of claim 1 , wherein detecting the obstacle comprises detecting the position and relative speed of the obstacle with respect to the vehicle using a noncontact distance detecting device.

4. The method of claim 1 , wherein predicting the type of collision comprises predicting any one of a full-wrap frontal collision, an offset frontal collision, a diagonal collision, a pole frontal collision and a rollover.

5. The method of claim 1 , wherein setting the conditions for expanding the airbag comprises setting a threshold value of impact force for activating an inflator of the airbag.

6. The method of claim 1 , wherein setting the conditions for expanding the airbag comprises setting an area of the opening provided in the airbag and predetermined time to change the opening area.

7. The method of claim 1 , wherein setting the conditions for expanding the airbag comprises setting a predetermined time to release a device for restricting the size of the expanded airbag.

8. The method for controlling an occupant restraint apparatus according of claim 1 , further comprising:

detecting status of an occupant of the vehicle before the setting of the conditions for expanding the airbag, and wherein setting the conditions for expanding the airbag is based on both the collision type and the occupant status.

9. An occupant restraint apparatus comprising:

an obstacle detecting device for detecting a position and relative speed of an obstacle with respect to a vehicle with the obstacle being in a travelling direction of the vehicle and potentially corning into collision with the vehicle;

a collision predicting device for predicting a type of collision between the obstacle detected by the obstacle detecting device and the vehicle;

a setting device for setting conditions for expanding an airbag of the vehicle based on the collision type predicted by the collision predicting device; and

an expansion controlling device including a flap member for controlling both the expansion size of the airbag and gas discharge from the airbag according to the conditions set by the setting device, wherein the flap member has one end fixed to the airbag and another end releasably connected to an inflator device for the airbag and has smaller and larger vents with one or the other of the vents being overlapped with an opening in the airbag depending on whether the other end of the flap member is connected or released from the inflator device based on the conditions set by the setting device.

10. The occupant restraint apparatus according to claim 9 , further comprising:

an occupant detecting device for detecting status of an occupant of the vehicle, with the setting device setting the conditions for expanding the airbag based on both the collision type and the occupant status.

11. The occupant restraint apparatus of claim 9 wherein the object detecting device comprises a sensor that detects the object prior to contact between the object and vehicle.

12. The occupant restraint apparatus of claim 9 wherein the setting device sets a threshold level of impact force for deployment of the airbag based on the predicted collision type.