As an auxiliary configuration for the passive safety of the vehicle body, the airbag has received increasing attention. When a car collides with an obstacle, it is called a collision. The occupant collides with the inner member of the vehicle. It is called a secondary collision. The airbag quickly opens a gas-filled air cushion after a collision and before the second collision, so that the occupant is inertia. When moving, "push on the air cushion" to mitigate the impact of the occupant and absorb the collision energy, reducing the damage of the occupant.