Control System Design for Occupant Lower Extremity Protection in Vehicle Frontal Collision

(Cooperative Control of Active Knee Bolster and Active Lap Belt)

Abstract

This paper presents control system design for occupant lower extremities protection in vehicle frontal 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. In the control system design, we examine the effects of the initial distance between the occupant's knees and the active knee bolster, and the maximum pelvis displacement. It is expected that the initial distance affects the protection performance because the control duration of the active knee bolster mainly depends on the initial distance. To avoid the collision with the steering wheel, the maximum pelvis displacement is restrained. The lap belt force and the contact force between the knees and the instrument panel are calculated so that the load to the femurs is reduced while the lap belt force is not increased compared to passive lap belt. Simulation results clarify the effects of the initial distance and the maximum pelvis displacement on occupant protection under assumption that the protective control system can vary the initial distance.