Control system design for occupant lower extremity protection in vehicle frontal collision

This paper presents control system design for occupant lower extremity protection in vehicle frontal collision. In order to protect the occupant's lower extremities in vehicle collision, a protective control system consisting of an active knee bolster and an active lap belt is designed to reduce the maximum load to the femurs and the maximum lap belt force. The lap belt force and the contact force between the knees and the instrument panel are controlled. The lap belt force acts on the pelvis. The contact force between the knees and the instrument panel acts on the lower limb after the knee collision. The control problem is formulated as reducing the load to lower extremities while restraining the occupant forward motion. The lap belt force and the contact force are calculated so that the load to the femurs is reduced while the lap belt force is not increased compared to passive lap belt. In this paper, we assume that the protective control system can vary the initial distance between the occupant's knees and the active knee bolster. Simulation results clarify the effects of the initial distance between the knees and the knee bolster on occupant protection.